Edgar Filing: GILEAD SCIENCES INC

Form 10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

x	ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2011

¨	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission File No. 0-19731

GILEAD SCIENCES, INC.

(Exact name of registrant as specified in its charter)


Delaware		94-3047598
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

333 Lakeside Drive, Foster City, California		94404
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code: 650-574-3000

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:


Title of each class		Name of each exchange on which registered
Common Stock, $0.001 par value per share		The Nasdaq Global Select Market

SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT: NONE

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes x No ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ¨ No x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x No ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x No ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. x

Indicate by check mark whether registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):


Large accelerated filer x	Accelerated filer ¨	Non-Accelerated filer ¨	Smaller reporting company ¨
	(Do not check if a smaller reporting company)

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ¨ No x

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant based upon the closing price of its Common Stock on the Nasdaq Global Select Market on June 30, 2011 was $ 29,933,970,092.*

The number of shares outstanding of the registrant’s Common Stock on February 10, 2012 was 757,315,361.

DOCUMENTS INCORPORATED BY REFERENCE

Specified portions of the registrant’s proxy statement, which will be filed with the Commission pursuant to Regulation 14A in connection with the registrant’s 2012 Annual Meeting of Stockholders, to be held on May 10, 2012, are incorporated by reference into Part III of this Report.

Based on a closing price of $41.41 per share on June 30, 2011. Excludes 48,586,996 shares of the registrant’s Common Stock held by executive officers, directors and any stockholders whose ownership exceeds 5% of registrant’s common stock outstanding at June 30, 2011. Exclusion of such shares should not be construed to indicate that any such person possesses the power, direct or indirect, to direct or cause the direction of the management or policies of the registrant or that such person is controlled by or under common control with the registrant.

GILEAD SCIENCES, INC.

2011 Form 10-K Annual Report

Table of Contents


PART I
Item 1	Business	2
Item 1A	Risk Factors	30
Item 1B	Unresolved Staff Comments	48
Item 2	Properties	48
Item 3	Legal Proceedings	49
Item 4	Mine Safety Disclosures	50

PART II
Item 5	Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	51
Item 6	Selected Financial Data	54
Item 7	Management’s Discussion and Analysis of Financial Condition and Results of Operations	56
Item 7A	Quantitative and Qualitative Disclosures about Market Risk	78
Item 8	Financial Statements and Supplementary Data	80
Item 9	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure	80
Item 9A	Controls and Procedures	80
Item 9B	Other Information	81

PART III
Item 10	Directors, Executive Officers and Corporate Governance	83
Item 11	Executive Compensation	83
Item 12	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	83
Item 13	Certain Relationships and Related Transactions, and Director Independence	83
Item 14	Principal Accountant Fees and Services	83

PART IV
Item 15	Exhibits and Financial Statement Schedules	84

SIGNATURES		153

We own or have rights to various trademarks, copyrights and trade names used in our business, including the following: GILEAD^®, GILEAD SCIENCES^®, TRUVADA^®, VIREAD^®, HEPSERA^®, AMBISOME^®, EMTRIVA^®, COMPLERA^®, EVIPLERA^®, VISTIDE^®, LETAIRIS^®, VOLIBRIS^®, RANEXA^®, CAYSTON^® and RAPISCAN^®. ATRIPLA^® is a registered trademark belonging to Bristol-Myers Squibb & Gilead Sciences, LLC. LEXISCAN^® is a registered trademark belonging to Astellas U.S. LLC. MACUGEN^® is a registered trademark belonging to Eyetech Inc. SUSTIVA^® is a registered trademark of Bristol-Myers Squibb Pharma Company. TAMIFLU^® is a registered trademark belonging to Hoffmann-La Roche Inc. This report also includes other trademarks, service marks and trade names of other companies.

This Annual Report on Form 10-K, including the section entitled “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” contains forward-looking statements regarding future events and our future results that are subject to the safe harbors created under the Securities Act of 1933, as amended (the Securities Act), and the Securities Exchange Act of 1934, as amended (the Exchange Act). Words such as “expect,” “anticipate,” “target,” “goal,” “project,” “hope,” “intend,” “plan,” “believe,” “seek,” “estimate,” “continue,” “may,” “could,” “should,” “might,” variations of such words and similar expressions are intended to identify such forward-looking statements. In addition, any statements other than statements of historical fact are forward-looking statements, including statements regarding overall trends, operating cost and revenue trends, liquidity and capital needs and other statements of expectations, beliefs, future plans and strategies, anticipated events or trends and similar expressions. We have based these forward-looking statements on our current expectations about future events. These statements are not guarantees of future performance and involve risks, uncertainties and assumptions that are difficult to predict. Our actual results may differ materially from those suggested by these forward-looking statements for various reasons, including those identified below under “Risk Factors,” beginning at page 30. Given these risks and uncertainties, you are cautioned not to place undue reliance on forward-looking statements. The forward-looking statements included in this report are made only as of the date hereof. Except as required under federal securities laws and the rules and regulations of the Securities and Exchange Commission (SEC), we do not undertake, and specifically decline, any obligation to update any of these statements or to publicly announce the results of any revisions to any forward-looking statements after the distribution of this report, whether as a result of new information, future events, changes in assumptions or otherwise.

PART I

ITEM 1.

BUSINESS

Overview

Gilead Sciences, Inc. (Gilead, we or us), incorporated in Delaware on June 22, 1987, is a research-based biopharmaceutical company that discovers, develops and commercializes innovative medicines in areas of unmet medical need. With each new discovery and experimental drug candidate, we seek to improve the care of patients suffering from life-threatening diseases around the world. Gilead’s primary areas of focus include human immunodeficiency virus (HIV)/AIDS, liver diseases such as hepatitis B and C and serious cardiovascular/metabolic and respiratory conditions. Headquartered in Foster City, California, we have operations in North America, Europe and Asia Pacific. We continue to seek to add to our existing portfolio of products through our internal discovery and clinical development programs and through a product acquisition and in-licensing strategy.

Over the past year, we executed our philosophy and strategy to bring best-in-class drugs to market. In keeping with this strategy, we completed several acquisitions and licensing transactions to enhance our pipeline. We also expanded our single-tablet regimen product offerings for the treatment of HIV with the launch of Complera/Eviplera (emtricitabine/rilpivirine/tenofovir disoproxil fumarate) and the anticipated 2012 launch of Quad, which combines four of our HIV medicines in a once-daily single-tablet regimen and is pending Food and Drug Administration (FDA) approval.

Our largest transaction was the acquisition of Pharmasset, Inc. in January 2012 for $11.1 billion. For several years, we have focused a large proportion of our research and development effort on discovering and advancing direct-acting antivirals for the treatment of chronic hepatitis C virus (HCV). The HCV therapeutic market has been and continues to be vastly underserved. Due to the limitations of available therapies, only a small fraction of individuals who are infected with HCV are diagnosed, and an even smaller fraction of those patients are treated. Prior to May 2011, when the first protease inhibitors were approved, only about half of the patients responded to the standard of care combination of pegylated interferon and ribavirin. The addition of protease inhibitors to the standard of care has resulted in incremental response rates for patients with genotype 1 infection; however, this regimen causes substantial side effects such as fatigue, bone marrow suppression, potentially debilitating rash, anemia and neuropsychiatric effects. As such, discontinuation rates with these triple therapy combinations have significantly increased.

Over the last two years, we have progressed several early stage HCV molecules with various mechanisms of action into clinical development. During 2011, the field of HCV research evolved rapidly, and it became clear our HCV portfolio of oral antiviral development compounds would have difficulty competing because it was behind the development programs of many of our competitors. Through our acquisition of Pharmasset, we gained ownership of GS-7977, the most advanced, and to date the most potent, nucleotide analog that acts to inhibit the replication of HCV with limited safety or resistance concerns detected thus far. The compound has been studied extensively in Phase 2 studies in genotype 2 and 3 infected patients in combination with ribavirin with or without pegylated interferon and is currently being studied in genotype 1 infected patients. The first of two Phase 3 trials, known as FISSION, evaluating GS-7977 in genotype 2 and 3 patients is currently enrolling. A second Phase 3 study of genotype 2 and 3 patients is scheduled to begin enrolling in the next few weeks. If Phase 3 data for genotype 2 and 3 patients is consistent with data from our Phase 2 trials, we would expect to file a new drug application (NDA) for the treatment of genotype 2 and 3 patients in 2013 for potential approval in late 2013 or early 2014.

Two thirds of HCV-infected individuals in the United States and Europe are infected with HCV genotype 1. We are conducting Phase 2 studies to determine the efficacy of GS-7977 plus ribavirin in this population. Results from these studies will be available over the next several months. We expect the first data evaluating GS-7977 plus ribavirin for 12 weeks in genotype 1 treatment-naïve patients from an arm of the QUANTUM study with 25 patients will be available at the end of the first quarter of 2012. We expect that this will be followed in the second quarter by data from an arm of the ELECTRON study involving 25 treatment-naïve patients treated for 12 weeks and, early in the third quarter, data on GS-7977 and ribavirin treatment for 24 weeks from an arm of the QUANTUM study will become available.

On February 17, 2012, we announced that the majority of HCV genotype 1 patients with a prior “null” response to an interferon-containing regimen enrolled in an arm of our ongoing ELECTRON study experienced viral relapse within four weeks of completing 12 weeks of treatment with GS-7977 plus ribavirin. Ten patients were randomized to this arm of the ELECTRON study and data were available for eight of the ten patients at the time of the announcement. Among these eight patients, six experienced viral relapse. Two patients had not relapsed; however, they had only reached the two week post-treatment time point. These data indicate that treatment of genotype 1 patients classified as null responders with GS-7977 plus ribavirin for 12 weeks will not be sufficient to cure their disease. Regulatory authorities require that patients have a sustained viral response for 12 weeks after the cessation of therapy to be considered “cured” of the disease.

To the extent data from the ELECTRON and QUANTUM studies indicate genotype 1 treatment-naïve patients can be effectively treated using GS-7977 and ribavirin, larger Phase 3 studies in genotype 1 patients are expected to commence in 2012. If we are able to commence Phase 3 trials on that timeline and the results of those trials are positive, we expect to file a NDA that includes data for genotype 1 patients in 2013 for potential approval in 2014. If GS-7977 with ribavirin is not sufficiently effective in treating genotype 1 treatment-naïve patients, we would need to explore combination therapy using GS-7977 and other direct acting antiviral compounds from our or others’ portfolios, which would delay development and approval of GS-7977 for use in genotype 1 treatment-naïve patients. We expect to begin clinical studies evaluating GS-7977 in combination with our GS-5885 NS5A inhibitor in genotype 1 treatment-naïve patients in the second quarter of 2012.

See the Risk Factor entitled “The public announcement of data from clinical studies evaluating GS-7977 in HCV-infected patients is likely to cause significant volatility in our stock price” on page 30.

Our Products

HIV/AIDS

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Atripla (efavirenz 600 mg/ emtricitabine 200 mg/ tenofovir disoproxil fumarate 300 mg) is an oral formulation dosed once a day for the treatment of HIV infection in adults. Atripla is the first once-daily single-tablet regimen for HIV intended as a stand alone therapy or in combination with other antiretrovirals. It is a fixed-dose combination of our antiretroviral medications, Viread (tenofovir disoproxil fumarate) and Emtriva (emtricitabine), and Bristol Myers-Squibb Company’s (BMS) non-nucleoside reverse transcriptase inhibitor, Sustiva (efavirenz).

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Truvada (emtricitabine and tenofovir disoproxil fumarate) is an oral formulation dosed once a day as part of combination therapy to treat HIV infection in adults. It is a fixed-dose combination of our antiretroviral medications, Viread and Emtriva.

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Viread is an oral formulation of a nucleotide analog reverse transcriptase inhibitor, dosed once a day as part of combination therapy to treat HIV infection in patients 2 years of age and older. Viread is also approved for the treatment of chronic hepatitis B in adults.

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Complera/Eviplera is an oral formulation dosed once a day for the treatment of HIV-1 infection in treatment-naïve adults. The product, marketed in the United States as Complera and in Europe as Eviplera, is the second complete single-tablet regimen for the treatment of HIV and is a fixed-dose combination of our antiretroviral medications, Viread and Emtriva, and Tibotec Pharmaceuticals’ non-nucleoside reverse transcriptase inhibitor, Edurant (rilpivirine).

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Emtriva is an oral formulation of a nucleoside analog reverse transcriptase inhibitor, dosed once a day as part of combination therapy to treat HIV infection in adults. In the United States and Europe, Emtriva is also available as an oral solution approved as part of combination therapy to treat HIV infection in children.

Liver Disease

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Viread is an oral formulation of a nucleotide analog reverse transcriptase inhibitor, dosed once a day for the treatment of chronic hepatitis B in adults with compensated and decompensated liver disease.

We have licensed to GlaxoSmithKline Inc. (GSK) the rights to commercialize Viread for the treatment of chronic hepatitis B in Asia and certain other territories. As noted above, Viread is also approved for the treatment of HIV infection in patients 2 years of age and older in combination with other antiretroviral agents.

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Hepsera (adefovir dipivoxil) is an oral formulation of a nucleotide analog polymerase inhibitor, dosed once a day to treat chronic hepatitis B in patients 12 years of age and older. We have licensed to GSK the rights to commercialize Hepsera for the treatment of chronic hepatitis B in Asia, Latin America and certain other territories.

Cardiovascular

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Letairis (ambrisentan) is an oral formulation of an endothelin receptor antagonist (ERA) indicated for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) in patients with WHO Class II or III symptoms to improve exercise capacity and delay clinical worsening. We sublicensed to GSK the rights to ambrisentan, marketed by GSK as Volibris (ambrisentan), for PAH in territories outside of the United States.

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Ranexa (ranolazine) is an extended-release tablet for the treatment of chronic angina. We have licensed to Menarini International Operations Luxembourg SA the rights to Ranexa in territories outside of the United States.

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Lexiscan/Rapiscan (regadenoson) injection is indicated for use as a pharmacologic stress agent in radionuclide myocardial perfusion imaging (MPI), a test that detects and characterizes coronary artery disease, in patients unable to undergo adequate exercise stress. Astellas US LLC has exclusive rights to manufacture and sell regadenoson under the name Lexiscan in the United States, subject to its obligations to pay us royalties based on sales of Lexiscan in the United States. Rapidscan Pharma Solutions, Inc. (RPS) holds the exclusive right to manufacture and sell regadenoson under the name Rapiscan in Europe and certain territories outside the United States. We receive royalties from Astellas and RPS for sales in these territories.

Respiratory

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Cayston (aztreonam for inhalation solution) is an inhaled antibiotic for the treatment of respiratory systems in cystic fibrosis (CF) patients 7 years of age and older with Pseudomonas aeruginosa (P. aeruginosa).

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Tamiflu (oseltamivir phosphate) is an oral antiviral available in capsule form for the treatment and prevention of influenza A and B. Tamiflu is approved for the treatment of influenza in children and adults in more than 60 countries, including the United States, Japan and the European Union. Tamiflu is also approved for the prevention of influenza in children and adults in the United States, Japan and the European Union. We developed Tamiflu with F. Hoffmann-La Roche Ltd (together with Hoffmann-La Roche Inc., Roche). Roche has the exclusive right to manufacture and sell Tamiflu worldwide, subject to its obligation to pay us royalties based on a percentage of the net sales of Tamiflu.

Other

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AmBisome (amphotericin B liposome for injection) is a proprietary liposomal formulation of amphotericin B, an antifungal agent to treat serious invasive fungal infections caused by various fungal species in adults. Our corporate partner, Astellas Pharma US, Inc., promotes and sells AmBisome in the United States and Canada, and we promote and sell AmBisome in Europe, Australia and New Zealand.

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Vistide (cidofovir injection) is an antiviral injection for the treatment of cytomegalovirus retinitis in adult patients with AIDS.

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Macugen (pegaptanib sodium injection) is an intravitreal injection of an anti-angiogenic oligonucleotide for the treatment of neovascular age-related macular degeneration. Macugen was

developed by Eyetech Inc. (Eyetech) using technology licensed from us and is now promoted in the United States by Eyetech. Eyetech holds the exclusive rights to manufacture and sell Macugen in the United States, and Pfizer Inc. (Pfizer) holds the exclusive right to manufacture and sell Macugen in the rest of the world. We receive royalties from Eyetech based on sales of Macugen worldwide.

The following table lists aggregate product sales for our major products (in thousands):


	2011		% of Total Product Sales		2010		% of Total Product Sales		2009		% of Total Product Sales
Antiviral products:
Atripla	$	3,224,518		40%	$	2,926,579		40%	$	2,382,113		37%
Truvada		2,875,141		35%		2,649,908		36%		2,489,682		38%
Viread		737,867		9%		732,240		10%		667,510		10%
Hepsera		144,679		2%		200,592		3%		271,595		4%
Complera/Eviplera		38,747		0%		—		—		—		—
Emtriva		28,764		0%		27,679		0%		27,974		0%

Total antiviral products		7,049,716		87%		6,536,998		88%		5,838,874		90%
AmBisome		330,156		4%		305,856		4%		298,597		5%
Letairis		293,426		4%		240,279		3%		183,949		3%
Ranexa		320,004		4%		239,832		3%		131,062		2%
Other		109,057		1%		66,956		1%		16,829		0%

Total product sales	$	8,102,359		100%	$	7,389,921		100%	$	6,469,311		100%

See Item 8, Note 16 to our Consolidated Financial Statements included in this Annual Report on Form 10-K, for our total revenues by geographic area.

Commercialization and Distribution

We have U.S. and international commercial sales operations, with marketing subsidiaries in Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong, Ireland, Italy, the Netherlands, New Zealand, Norway, Poland, Portugal, South Korea, Spain, Sweden, Switzerland, Turkey, the United Kingdom and the United States.

Our products are marketed through our commercial teams and/or in conjunction with third-party distributors and corporate partners. Our commercial teams promote our products through direct field contact with physicians, hospitals, clinics and other healthcare providers. We generally grant our third-party distributors the exclusive right to promote our product in a territory for a specified period of time. Most of our agreements with these distributors provide for collaborative efforts between the distributor and Gilead in obtaining and maintaining regulatory approval for the product in the specified territory.

We sell and distribute Atripla, Truvada, Viread, Hepsera, Complera, Emtriva, Ranexa and Vistide in the United States exclusively through the wholesale channel. Our product sales to three large wholesalers, Cardinal Health, Inc., McKesson Corp. and AmerisourceBergen Corp., each accounted for more than 10% of total revenues for each of the years ended December 31, 2011, 2010 and 2009. On a combined basis, in 2011, these wholesalers accounted for approximately 79% of our product sales in the United States and approximately 43% of our total worldwide revenues. Letairis and Cayston are distributed exclusively by specialty pharmacies. These specialty pharmacies dispense medications for complex or chronic conditions that require a high level of patient education and ongoing counseling. We sell and distribute Atripla, Truvada, Viread, Hepsera, Emtriva, Complera/Eviplera, and AmBisome in Asia, Australia, Canada, Europe, Latin America, the Middle East and New Zealand either through our commercial teams, third-party distributors or corporate partners.

We also rely on our corporate partners to help promote and sell our products under collaboration agreements. For example, BMS has rights to promote Atripla in the United States. BMS also has rights to promote Atripla in a majority of the countries in Europe. In a limited number of Central and Eastern European countries, either Gilead, BMS or a third-party distributor is the sole promoting, selling and distributing company. Under an agreement with Merck & Co., Inc. (Merck), we promote and distribute Atripla in 12 countries in Latin America and Asia Pacific either through Merck or our existing third-party distributors. We have licensed to GSK the right to promote and sell Viread and Hepsera for the treatment of hepatitis B in certain countries outside the United States. We licensed the rights to manufacture and sell Tamiflu, Macugen and Lexiscan/Rapiscan worldwide to third parties, subject to our corporate partners’ obligation to pay us royalties based on a percentage of the sales of these products.

Access in the Developing World

Through the Gilead Access Program, established in 2003, certain of our HIV and other products are available at substantially reduced prices in 134 countries in the developing world. We have developed a system of tiered pricing that reflects economic status, using gross national income per capita (GNI) and HIV prevalence. This approach allows us to price our therapies based on a country’s ability to pay.

We also support many clinical studies through the donation of our products to help define the best treatment strategies in developing world countries. For example, we donated tenofovir for the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 microbicide trial, which assessed the effectiveness and the safety of a tenofovir-based microbicide gel for the prevention of HIV infection in South African women. We also provide drugs for a number of innovative international studies investigating whether Viread or Truvada can prevent HIV transmission among at-risk, uninfected adults. This is a potential HIV prevention strategy called pre-exposure prophylaxis, or PrEP. In December 2011, we announced the submission of a supplemental NDA (sNDA) to the FDA for the approval of once-daily Truvada for PrEP to reduce the risk of HIV-1 infection among uninfected adults. If the sNDA is approved, Truvada would be the first agent indicated for uninfected individuals to reduce the risk of acquiring HIV through sex.

We also work closely with the World Health Organization and with non-governmental organizations to provide AmBisome for the treatment of leishmaniasis, a parasitic disease, at a preferential price in resource limited settings. We support numerous clinical studies investigating the role of AmBisome to treat visceral and cutaneous leishmaniasis in developing countries through collaborations with organizations such as the Drugs for Neglected Diseases initiative and Médecins Sans Frontières. We also support clinical research studies aimed at identifying the best treatment course for visceral leishmaniasis and donated AmBisome to support clinical studies assessing combination therapies and the cost-effectiveness of multiple visceral leishmaniasis treatment interventions. In December 2011, we signed a partnership agreement with World Health Organization to donate 445,000 vials of AmBisome over five years. This donation will be used to treat more than 50,000 patients in resource-limited countries.

We have also entered into a number of collaborations related to access to our products in the developing world, which include:

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PharmaChem Technologies (Grand Bahama), Ltd (PharmaChem). In 2005, PharmaChem, one of our commercial manufacturing partners, established a facility in The Bahamas to manufacture tenofovir disoproxil fumarate, the active pharmaceutical ingredient in Viread and one of the active pharmaceutical ingredients in Atripla and Truvada, for resource limited countries through a cooperative effort with PharmaChem and the Grand Bahama Port Authority. This partnership increases manufacturing capacity for our HIV medicines, and improve delivery efficiency, since the medicines are produced in or near the markets where they are needed most.

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Aspen Pharmacare Holdings Ltd (Aspen). In 2005, we entered into a non-exclusive manufacturing and distribution agreement with Aspen, providing for the manufacture and distribution of Viread and Truvada for the treatment of HIV infection to certain developing world countries included in our Gilead Access Program. In 2007, we amended our agreement with Aspen. Under the amended

agreement, Aspen retained the right to manufacture and distribute Viread and Truvada for the treatment of HIV infection in these developing world countries. Aspen has the right to purchase Viread and Truvada in unlabeled bottles from us for distribution in such countries, and also has the right to manufacture Viread and Truvada using active pharmaceutical ingredient that has been purchased by Aspen from suppliers approved by us. Aspen was also granted the right to manufacture and distribute generic versions of emtricitabine and tenofovir disoproxil fumarate, including versions of tenofovir disoproxil fumarate in combination with emtricitabine for the treatment of HIV infection. Aspen is required to pay us royalties on net sales of Viread and Truvada, as well as royalties on net sales of generic versions of tenofovir disoproxil fumarate, including versions of tenofovir disoproxil fumarate in combination with generic versions of emtricitabine that are manufactured and distributed by Aspen.

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Licenses with Generic Manufacturers. In 2006, we entered into non-exclusive license agreements with thirteen Indian generic manufacturers, granting them the rights to produce and distribute generic versions of tenofovir disoproxil fumarate for the treatment of HIV infection to low income countries around the world, which includes India and many of the low income countries in our Gilead Access Program. The agreements require that the generic manufacturers meet certain national and international regulatory standards and include technology transfers to enable expeditious production of large volumes of high quality generic versions of tenofovir disoproxil fumarate. In addition, these agreements allow for the manufacture of commercial quantities of both active pharmaceutical ingredient and finished product. In 2011, we expanded these non-exclusive license agreements to increase the number of countries included in the license, and also to include rights to our future pipeline products elvitegravir, an investigational integrase inhibitor; cobicistat, an investigational antiretroviral boosting agent; and Quad, which combines four of our HIV medicines in a once-daily single-tablet regimen and is pending FDA approval. To expand access to Viread for the treatment of hepatitis B treatment in developing countries, we also included in these non-exclusive license agreements the ability to manufacture and distribute generic versions of tenofovir disoproxil fumarate for the treatment of hepatitis B in the same countries where they are authorized to sell generic versions of tenofovir disoproxil fumarate for HIV.

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Merck. In 2006, we entered into an agreement with an affiliate of Merck pursuant to which Gilead and Merck provide Atripla at substantially reduced prices to HIV infected patients in developing countries in Africa, the Caribbean, Latin America and Southeast Asia. Under the agreement, we manufacture Atripla using efavirenz supplied by Merck, and Merck handles distribution of the product in the countries covered by the agreement.

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International Partnership for Microbicides (IPM) and CONRAD. In 2006, we entered into an agreement under which we granted rights to IPM and CONRAD, a cooperating agency of the U.S. Agency for International Development committed to improving reproductive health by expanding the contraceptive choices of women and men, to develop, manufacture, and, if proven efficacious, arrange for the distribution in resource limited countries of certain formulations of tenofovir for use as a topical microbicide to prevent HIV infection.

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Medicines Patent Pool (the Pool). In 2011, we entered into an agreement with the Pool, an organization that was established by the United Nations to increase global access to high-quality, low-cost antiretroviral therapy through the sharing of patents. We granted the Pool a non-exclusive license to identify generic pharmaceutical manufacturers in India who specialize in high-quality production of generic medicines and grant sublicenses to those Indian manufacturers to manufacture and distribute generic versions of our antiretrovirals in the developing world. Sublicensees through the Pool will be free to develop combination products and pediatric formulations of our HIV medicines. We also granted the Pool the right to grant sublicenses to our future pipeline products elvitegravir, cobicistat and Quad to those same generic pharmaceutical manufacturers in India for distribution in the developing world.

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Tibotec Pharmaceuticals (Tibotec). In 2011, we expanded our agreement with Tibotec to provide for distribution of Complera/Eviplera for the treatment of HIV in less developed countries and to enable the commercialization of generic versions of the product.

Competition

Our products target a number of areas, including viral, cardiovascular, respiratory and fungal diseases. There are many commercially available products for the treatment of these diseases. Many companies and institutions are making substantial investments in developing additional products to treat these diseases. Our products compete with other available products based primarily on:

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efficacy;

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safety;

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tolerability;

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acceptance by doctors;

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ease of patient compliance;

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patent protection;

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ease of use;

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price;

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insurance and other reimbursement coverage;

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distribution; and

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marketing.

Our HIV Products

The HIV landscape is becoming more competitive and complex as treatment trends continue to evolve. A growing number of anti-HIV drugs are currently sold or are in advanced stages of clinical development. Competition from current and expected competitors may erode the revenues we receive from sales of our HIV products. Of the 35 branded HIV drugs available in the United States, our products primarily compete with the fixed-dose combination products in the nucleotide/nucleoside reverse transcriptase inhibitors (NRTI) class, including Combivir (lamivudine/zidovudine), Epzicom/Kivexa (abacavir/lamivudine) and Trizivir (abacavir/lamivudine/zidovudine), each sold by a joint venture, ViiV, that was established in November 2009 by GSK and Pfizer focused on HIV therapies. Our HIV products also compete broadly with HIV products from Abbott Laboratories, Inc., Boehringer Ingelheim GmbH, Merck, Roche and Tibotec.

BMS’s Videx EC (didanosine, ddI) became the first generic HIV product in the United States in 2004. GSK’s Retrovir (zidovudine) also faces generic competition in the United States as a result of the launch of generic zidovudine in 2005. BMS’s Zerit (stavudine) also faces generic competition in the United States as a result of the launch of generic stavudine in 2008. Lamivudine, marketed by ViiV, is competitive with emtricitabine, the active pharmaceutical ingredient of Emtriva and a component of Atripla, Truvada and Complera/Eviplera. In May 2010, the compound patent covering Epivir (lamivudine) itself expired in the United States, and generic lamivudine is now available in the United States, Spain and Portugal, and recently received pricing approval in Italy. We expect that generic versions of lamivudine will be launched in other countries within the European Union. In May 2011, a generic version of Combivir (lamivudine and zidovudine) was approved and was recently launched in the United States. In addition, in late 2011, generic tenofovir also became available in Turkey. To date, there has not been a significant impact from generic didanosine, zidovudine, stavudine, lamivudine, the generic version of Combivir or generic tenofovir in Turkey on the price of our HIV products; however, price decreases for all HIV products may result in the longer term.

Our Liver Disease Products

Our hepatitis B virus (HBV) products, Viread and Hepsera, face significant competition from existing and expected therapies for treating patients with chronic hepatitis B, which may erode the revenues we receive from sales of our HBV products. Our HBV products face competition from Baraclude (entecavir), an oral nucleoside

analog developed by BMS and launched in the United States in 2005, and Tyzeka/Sebivo (telbivudine), an oral nucleoside analog developed by Novartis Pharmaceuticals Corporation (Novartis) for sale in the United States, the European Union and China.

Our HBV products also compete with Epivir-HBV/Zeffix (lamivudine), which was developed by GSK in collaboration with Shire Pharmaceuticals Group PLC and is sold in the major countries throughout North and South America, Europe and Asia.

Viread and Hepsera for the treatment of chronic hepatitis B also compete with established immunomodulatory therapies, including Intron-A (interferon alfa-2b), which is sold by Schering Plough Corporation in major countries throughout North and South America, Europe and Asia, and Pegasys (pegylated interferon alfa-2a), an injectable drug similar to Intron-A sold by Roche for the treatment of chronic hepatitis B.

Our Cardiovascular Products

Letairis competes directly with Tracleer (bosentan) sold by Actelion Pharmaceuticals US, Inc. (Actelion) and indirectly with a PAH product from United Therapeutics Corporation.

Ranexa competes predominantly with generic compounds from three distinct classes of drugs for the treatment of chronic angina in the United States, including generic and/or branded beta-blockers, calcium channel blockers and long-acting nitrates. In addition, surgical treatments and interventions such as coronary artery bypass grafting and percutaneous coronary intervention can be another option for angina patients, and may be perceived by healthcare practitioners as preferred methods to treat the cardiovascular disease that underlies and causes angina.

There are numerous marketed generic and/or branded pharmacologic stress agents that compete with Lexiscan/Rapiscan. Clinical Data, Inc. is developing apadenoson as a pharmacologic stress agent for MPI which is currently in Phase 3 clinical trials. These stress agents and product candidates could also compete with Lexiscan/Rapiscan.

Our Respiratory Products

Cayston competes primarily with Tobi (tobramycin inhalation solution), an inhaled medication sold by Novartis for the treatment of CF patients whose lungs contain P. aeruginosa.

Tamiflu competes with Relenza (zanamivir), an anti-influenza drug that is sold by GSK. Relenza is a neuraminidase inhibitor that is delivered as an orally-inhaled dry powder. Generic competitors include amantadine and rimantadine, both oral tablets that only inhibit the replication of the influenza A virus. BioCryst Pharmaceuticals, Inc. is developing injectable formulations of peramivir, an influenza neuraminidase inhibitor, for the treatment of influenza, which are currently in Phase 3 clinical trials.

Our Other Products

AmBisome faces strong competition from several current and expected competitors. Competition from these current and expected competitors may erode the revenues we receive from sales of AmBisome. AmBisome faces competition from Vfend (voriconazole) developed by Pfizer and caspofungin, a product developed by Merck that is marketed as Cancidas in the United States and as Caspofungin elsewhere. AmBisome also competes with other lipid-based amphotericin B products, including Abelcet (amphotericin B lipid complex injection), sold by Enzon Pharmaceuticals, Inc. in the United States, Canada and Japan and by Zeneus Pharma Ltd. in Europe; Amphotec (amphotericin B cholesteryl sulfate complex for injection), sold by Three Rivers Pharmaceuticals, LLC worldwide; and Anfogen (amphotericin B liposomal), sold by Genpharma, S.A. in Argentina. BMS and numerous generic manufacturers sell conventional amphotericin B, which also competes with AmBisome.

We are aware of at least two lipid formulations that claim similarity to AmBisome becoming available outside of the United States, including the possible entry of one such formulation in Greece. These formulations may reduce market demand for AmBisome. The manufacture of lipid formulations of amphotericin B is very complex, and if any of these formulations are found to be unsafe, sales of AmBisome may be negatively impacted by association.

Vistide competes with a number of drugs that also treat cytomegalovirus retinitis, including Cytovene IV and Cytovene (ganciclovir), sold in intravenous and oral formulations, respectively, by Roche and as an ocular implant by Bausch & Lomb Incorporated; Valcyte (valganciclovir), also marketed by Roche; Foscavir (foscarnet), an intravenous drug sold by AstraZeneca PLC; and Vitravene (fomivirsen), a drug injected directly into the eye, sold by CibaVision.

Macugen competes primarily with Visudyne (verteporfin for injection), which is sold by Novartis and used in connection with photodynamic therapy, and Lucentis (ranibizumab), which is sold by Genentech, Inc. in the United States and Novartis in territories outside the United States.

A number of companies are pursuing the development of technologies which are competitive with our research programs. These competing companies include specialized pharmaceutical firms and large pharmaceutical companies acting either independently or together with other pharmaceutical companies. Furthermore, academic institutions, government agencies and other public and private organizations conducting research may seek patent protection and may establish collaborative arrangements for competitive products and programs.

Collaborative Relationships

As part of our business strategy, we establish collaborations with other companies, universities and medical research institutions to assist in the clinical development and/or commercialization of certain of our products and product candidates and to provide support for our research programs. We also evaluate opportunities for acquiring products or rights to products and technologies that are complementary to our business from other companies, universities and medical research institutions. More information regarding certain of these relationships, including their ongoing financial and accounting impact on our business can be found in Item 8, Note 10 to our Consolidated Financial Statements included in this Annual Report on Form 10-K.

Commercial Collaborations

Although we currently have a number of collaborations with corporate partners that govern the manufacture, sale, distribution and/or marketing of our products in various territories worldwide, the following commercial collaborations are those that are most significant to us from a financial statement perspective and where significant ongoing collaboration activity exists.

•

Roche. In 1996, we entered into a development and license agreement with Roche to develop and commercialize therapies to treat and prevent viral influenza. Tamiflu, an antiviral oral formulation for the treatment and prevention of influenza, was co-developed by us and Roche. Under the original agreement, Roche had the exclusive right and obligation to manufacture and sell Tamiflu worldwide, subject to its obligation to pay us a percentage of the net sales that Roche generated from Tamiflu sales. Under the agreement, we received an up-front payment in the amount of $5.0 million and were entitled to receive additional milestone payments of up to $40.0 million upon the achievement of certain development and regulatory objectives. We have received all such milestone payments. In 1996, Roche also made a cash payment to us in the amount of $5.3 million related to reimbursement for certain research and preclinical development expenses and our obligation to prosecute and maintain certain patents under the agreement. In 2005, we entered into a first amendment and supplement to the original agreement with Roche. The amendment eliminated cost of goods adjustments from the royalty calculation, retroactive to calendar year 2004 and for all future calculations. The amendment also

provided for the formation of a joint manufacturing committee to review Roche’s manufacturing capacity for Tamiflu and global plans for manufacturing Tamiflu, a U.S. commercial committee to evaluate commercial plans and strategies for Tamiflu in the United States and a joint supervisory committee to evaluate Roche’s overall commercial plans for Tamiflu on a global basis. Each of the committees consists of representatives from both Roche and us. Under the amendment, we have the option to provide a specialized sales force to supplement Roche’s U.S. marketing efforts for Tamiflu, which we have not exercised to date. The agreement and Roche’s obligation to pay royalties to us will terminate on a country-by-country basis as patents providing exclusivity for Tamiflu in such countries expire. Roche may terminate the agreement for any reason in which case all rights to Tamiflu would revert to us. Either party may terminate the agreement in response to a material breach by the other party.

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BMS. In 2004, we entered into a collaboration with BMS to develop and commercialize the single-tablet regimen of our Truvada and BMS’s Sustiva in the United States. This combination was approved for use in the United States in 2006 and is sold under the brand name Atripla. We and BMS structured this collaboration as a joint venture by forming a limited liability company called Bristol-Myers Squibb & Gilead Sciences, LLC. Under the terms of the collaboration, we and BMS granted royalty free sublicenses to the joint venture for the use of our respective company owned technologies and, in return, were granted a license by the joint venture to use any intellectual property that results from the collaboration. The economic interests of the joint venture held by us and BMS (including share of revenues and out-of-pocket expenses) are based on the portion of the net selling price of Atripla attributable to Truvada and Sustiva, respectively. Since the net selling price for Truvada may change over time relative to the net selling price of Sustiva, both our and BMS’s respective economic interests in the joint venture may vary annually. We and BMS share marketing and sales efforts, with both parties providing equivalent sales force efforts at levels agreed to annually by BMS and Gilead. Since the second quarter of 2011, except for a limited number of activities that will be jointly managed, the parties no longer coordinate detailing and promotional activities in the United States and the parties have begun to reduce their joint promotional efforts in Canada as we launch Complera and in anticipation of the launch of Quad. The parties continue to collaborate on activities such as manufacturing, regulatory, compliance and pharmacovigilance. The daily operations of the joint venture are governed by four primary joint committees formed by both BMS and Gilead. We are responsible for accounting, financial reporting, tax reporting and product distribution for the joint venture. In 2006, we and BMS amended the joint venture’s collaboration agreement to allow the joint venture to sell Atripla into Canada. The agreement will continue until terminated by the mutual agreement of the parties. In addition, either party may terminate the other party’s participation in the collaboration within 30 days after the launch of at least one generic version of such other party’s single agent products (or the double agent products). The non-terminating party then has the right to continue to sell Atripla, but will be obligated to pay the terminating party certain royalties for a three-year period following the effective date of the termination.

In 2007, we entered into a collaboration agreement with BMS which sets forth the terms and conditions under which we and BMS commercialize Atripla in the European Union, Iceland, Liechtenstein, Norway and Switzerland. Either we, BMS or a third-party distributor act as the selling party in these countries and are responsible for, among other things, receiving and processing customer orders, warehousing product, collecting receivables and handling returns. Manufacturing of Atripla is coordinated by us, and we are primarily responsible for distribution logistics. In general, the parties share revenues and out-of-pocket expenses in proportion to the net selling prices of Truvada, with respect to us, and efavirenz, with respect to BMS. Starting in 2012, except for a limited number of activities that will be jointly managed, the parties will no longer coordinate detailing and promotional activities in the region. The agreement will terminate upon the expiration of the last-to-expire patent which affords market exclusivity to Atripla or one of its components in the European countries covered by the agreement. Prior to such time, either party may terminate the agreement for any reason, with such termination to be effective in December 2013. The non-terminating party has the right to continue

to sell Atripla, but will be obligated to pay the terminating party certain royalties for a three-year period following the effective date of the termination. In the event the non-terminating party decides not to sell Atripla, the effective date of the termination will be the date Atripla is withdrawn in each country or the date on which a third party assumes distribution of Atripla, whichever is earlier.

•

GSK. In 2006, we sublicensed to GSK exclusive rights to market ambrisentan (the active pharmaceutical ingredient in Letairis) under the name Volibris for PAH in territories outside of the United States. Under the license agreement, we received an up-front payment of $20.0 million and, subject to the achievement of specific milestones, we are eligible to receive total additional milestone payments of $80.0 million. Through December 31, 2011, we have received $55.0 million of such potential milestone payments. In addition, we will receive royalties based on net sales of Volibris in the GSK territories. GSK has an option to negotiate from us an exclusive sublicense for additional therapeutic uses for Volibris in the GSK territories during the term of the license agreement. Under the agreement, we will continue to conduct and bear the expense of all clinical development activities that we believe are required to obtain and maintain regulatory approvals for Letairis and Volibris in the United States, Canada and the European Economic Area, and each party may conduct additional development activities in its territories at its own expense. The parties may agree to jointly develop ambrisentan for new indications in the licensed field, and each party will pay its share of external costs associated with such joint development. The agreement and GSK’s obligation to pay royalties to us will terminate on a country-by-country basis on the earlier of the date on which generic equivalents sold in a country achieve a certain percentage of total prescriptions for the product plus its generic equivalents or the fifteenth anniversary of commercial launch in such country. GSK may terminate the agreement for any reason. Upon such termination, all rights to the product would revert to us. Either party may terminate the agreement in response to a material breach by the other party.

•

Tibotec. In 2009, we entered into a collaboration agreement with Tibotec to develop and commercialize a fixed-dose combination of our Truvada and Tibotec’s rilpivirine. This combination was approved in the United States and European Union in 2011 and is sold under the brand name Complera in the United States and Eviplera in the European Union. Under the agreement, Tibotec granted us an exclusive license to Complera/Eviplera worldwide excluding certain middle income and developing world countries and Japan. Neither party is restricted from combining its drugs with any other drugs.

Through December 31, 2011, we recorded €71.5 million (approximately $100.0 million) in reimbursable R&D expenses incurred by Tibotec in the development of rilpivirine, which is the maximum amount reimbursable under the terms of the agreement. We are responsible for manufacturing Complera/Eviplera and have the lead role in registration, distribution and commercialization of the product in the licensed countries. Tibotec has exercised a right to co-detail the combination product in the countries where Gilead is the selling party. The price of the product is expected to be the sum of the price of Truvada and the price of rilpivirine purchased separately. The cost of rilpivirine purchased by us from Tibotec for Complera/Eviplera will approximate the market price of rilpivirine, less a specified percentage of up to thirty percent (30%).

In July 2011, we amended the collaboration agreement to include distribution of Complera/Eviplera in the rest of the world. We will distribute the product in North America, Europe, Latin America, Australia and New Zealand, while Tibotec will distribute the product in the other regions, including Japan and Russia.

Either party may terminate the collaboration agreement if Complera/Eviplera is withdrawn from the market or if a party materially breaches the agreement. We may terminate the agreement in the United States and Canada on or after the expiration of the last to expire patent for tenofovir disoproxil fumarate in the United States, and may terminate the agreement in any other country on or after the expiration of the last to expire patent for tenofovir disoproxil fumarate in a country of the European Union. Tibotec may terminate the agreement in the United States and Canada on or after the expiration

of the last to expire patent for rilpivirine in the United States, and may terminate the agreement in any other country on or after the expiration of the last to expire patent for rilpivirine in a country of the European Union.

Research Collaborations

We currently have a number of collaborations with corporate partners that govern our research and development (R&D) of certain compounds and drug candidates. Our research collaboration with Japan Tobacco Inc. (Japan Tobacco) is the only collaboration that is significant to us from a financial statement perspective and where significant ongoing collaboration activity exists.

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Japan Tobacco. In 2005, we entered into a licensing agreement with Japan Tobacco, under which Japan Tobacco granted us exclusive rights to develop and commercialize elvitegravir, a novel HIV integrase inhibitor, in all countries of the world, excluding Japan, where Japan Tobacco would retain such rights. Under the agreement, we are responsible for seeking regulatory approval in our territories and are required to use diligent efforts to commercialize a product for the treatment of HIV infection. We will bear all costs and expenses associated with such commercialization efforts. Under the terms of the agreement, we paid an up-front license fee of $15.0 million and are obligated to make total potential milestone payments of up to $90.0 million upon the achievement of certain clinical, regulatory and commercial objectives. Additionally, we are obligated to pay royalties based on any net sales in the territories where we market the product. Through December 31, 2011, we have made total milestone payments of $28.0 million. The agreement and our obligation to pay royalties to Japan Tobacco will terminate on a product-by-product basis as patents providing exclusivity for the product expire or, if later, on the tenth anniversary of commercial launch for such product. We may terminate the agreement for any reason in which case the license granted by Japan Tobacco to us would terminate. Either party may terminate the agreement in response to a material breach by the other party.

Research and Development

Our research and development philosophy and strategy is to develop best-in-class drugs that improve safety or efficacy for unmet medical needs. We apply our expertise in drug discovery and development to target specific medical needs where new or better treatments are needed. We intend to continue committing significant resources to research and development opportunities and business development activity.

Our product development efforts cover a wide range of medical conditions, including HIV/AIDS and liver diseases such as hepatitis B and C and cardiovascular/metabolic, respiratory and inflammation/oncology diseases. We have research scientists in Foster City, Palo Alto, San Dimas and Oceanside, California; Branford, Connecticut; Princeton, New Jersey; and Seattle, Washington, engaged in the discovery and development of new molecules and technologies that we hope will lead to new medicines and novel formulations of existing drugs.

The development of our product candidates is subject to various risks and uncertainties. These risks and uncertainties include our ability to enroll patients in clinical trials, the possibility of unfavorable results of our clinical trials, the need to modify or delay our clinical trials or to perform additional trials and the risk of failing to obtain regulatory approvals. As a result, our product candidates may never be successfully commercialized. Drug development is inherently risky and many product candidates fail during the drug development process.

Below is a summary of our key product candidates and their corresponding current stages of development. For additional information on our development pipeline, visit our website at www.gilead.com.

Product Candidates for the Treatment of HIV


Product Candidates		Description
Marketing Application Pending

Integrase Single-Tablet Regimen “Quad”		In October 2011, we submitted a new drug application (NDA) to the U.S. Food and Drug Administration (FDA) for marketing approval of the once-daily, single-tablet “Quad” regimen of elvitegravir, cobicistat, tenofovir disoproxil fumarate and emtricitabine. In December 2011, the FDA accepted the NDA for review and set a target review date of August 27, 2012. In addition, FDA indicated that a panel would be convened in the May 2012 timeframe to provide expert advice on the application. Also in December 2011, we announced that we had submitted a marketing authorization application to the European Medicines Agency for marketing approval of this single-tablet regimen.

Phase 3

Cobicistat		Cobicistat is a pharmacoenhancer that is under evaluation as a boosting agent for certain HIV medicines in treatment-naïve patients. Based on positive clinical trial results, we expect to submit a NDA for the product in the second quarter of 2012.

Elvitegravir		Elvitegravir is an oral integrase inhibitor that is being evaluated as part of combination therapy for HIV in treatment-experienced patients. Based on positive clinical trial results, we expect to submit a NDA for the product in the second quarter of 2012.

Phase 2

GS-7340		GS-7340 is a nucleotide reverse transcriptase inhibitor being evaluated for the treatment of HIV/AIDS.

Product Candidates for the Treatment of Liver Disease


Product Candidates		Description
Phase 3

GS-7977		GS-7977 is a nucleotide NS5B inhibitor under evaluation for the treatment of HCV. We are currently enrolling genotype 2 and 3 patients in a Phase 3 clinical program of GS-7977 and ribavirin. We are also evaluating GS-7977 in combination with ribavirin in genotype 1 treatment-naïve and “null” responder patients. Null responders are patients who did not respond to earlier interferon-based therapy. On February 17, 2012, we announced that the majority of HCV genotype 1 patients with a prior “null” response to an interferon-containing regimen enrolled in an arm of our ongoing ELECTRON study experienced viral relapse within four weeks of completing 12 weeks of treatment with GS-7977 plus ribavirin. Ten patients were randomized to this arm of the ELECTRON study and data were available for eight of the ten patients at the time of the announcement. Among these eight patients, six experienced viral relapse. Two patients had not relapsed; however, they had only reached the two week post-treatment time point. Further data from the genotype 1 null responder


Product Candidates		Description
		arm of the study will be presented at an upcoming scientific conference. These data indicate that treatment of genotype 1 patients classified as null responders with GS-7977 plus ribavirin for 12 weeks will not be sufficient to cure their disease. We expect to receive data from ongoing studies of treatment-naïve patients with GS-7977 and ribavirin over the next several months, as described in “Overview” in Item 1, Business.

Phase 2

GS-5885		GS-5885 is an oral NS5A inhibitor under evaluation for the treatment of hepatitis C.

GS-9256*		GS-9256 is an NS3 oral protease inhibitor being evaluated for the treatment of hepatitis C.

GS-9451		GS-9451 is an oral NS3 protease inhibitor being evaluated for the treatment of hepatitis C.

*	No further clinical trials planned at this time.


Product Candidates		Description
Tegobuvir (GS-9190)*		Tegobuvir (GS-9190) is an oral NS5B non-nucleoside polymerase inhibitor being evaluated for the treatment of hepatitis C.

GS-6624		GS 6624 is a monoclonal antibody being evaluated for the treatment of liver fibrosis.

Phase 1

GS-7340		GS-7340 is a nucleoside reverse transcriptase inhibitor under evaluation for the treatment of hepatitis B.

GS-9620		GS-9620 is an oral TLR-7 agonist for the treatment of hepatitis B and hepatitis C.

GS-9669		GS-9669 is a non-nucleoside polymerase inhibitor under evaluation for the treatment of hepatitis C.

*	No further clinical trials planned at this time.

Product Candidates for the Treatment of Cardiovascular/Metabolic Diseases


Product Candidates		Description
Phase 3

Ranolazine		Ranolazine is a late sodium current inhibitor approved for the treatment of chronic angina, which will also be evaluated for the treatment of incomplete revascularization post-percutaneous coronary intervention and the treatment of type II diabetes. We expect to complete the Phase 3 trial evaluating ranolazine for the treatment of incomplete revascularization post-percutaneous coronary intervention in the first half of 2014 and the Phase 3 trial evaluating ranolazine for the treatment of treatment of type II diabetes in the second half of 2013.

Product Candidates for the Treatment of Respiratory Diseases


Product Candidates		Description
Phase 3

Aztreonam for inhalation solution		Aztreonam for inhalation solution is being evaluated for the treatment of bronchiectasis. We expect to complete enrollment of the two Phase 3 trials by early 2013.

Phase 1

GS-6624		GS-6624 is a monoclonal antibody being evaluated for the treatment of idiopathic pulmonary fibrosis.

Product Candidates for the Treatment of Inflammation/Oncology Diseases


Product Candidates		Description
Phase 3

GS-1101		GS-1101 is a PI3K delta inhibitor antibody being evaluated for the treatment of chronic lymphocytic leukemia. We expect to complete enrollment of the first Phase 3 trial of GS-1101 for the treatment of chronic lymphocytic leukemia in the first half of 2013.

Phase 2

GS-1101		GS-1101 is a PI3K delta inhibitor antibody being evaluated for the treatment of indolent non-Hodgkin’s lymphoma.

GS-6624		GS-6624 is a monoclonal antibody being evaluated for the treatment of myelofibrosis, colorectal cancer and pancreatic cancer.

Phase 1

GS-9973		GS-9973 is a Syk inhibitor being evaluated for the treatment of rheumatoid arthritis.

In total, our R&D expenses for 2011 were $1.23 billion compared with $1.07 billion for 2010 and $939.9 million for 2009. In addition to our internal discovery and clinical development programs, we seek to add to our portfolio of products through product acquisitions and collaborations. The following table shows some of our recent acquisitions:


Year	Company	Therapeutic area
2009	CV Therapeutics, Inc.	Cardiovascular disorders
2010	CGI Pharmaceuticals, Inc.	Serious inflammatory diseases
2011	Arresto Biosciences, Inc.	Fibrotic diseases and cancer
2011	Calistoga Pharmaceuticals, Inc.	Cancer and inflammatory diseases
2012	Pharmasset, Inc.	Chronic hepatitis C virus

Our largest transaction was the acquisition of Pharmasset, Inc. in January 2012 for $11.1 billion. Pharmasset was a clinical-stage pharmaceutical company located in Princeton, New Jersey, committed to discovering, developing and commercializing novel drugs to treat viral infections. Pharmasset’s primary focus was the development of oral therapeutics for the treatment of HCV infection. Through our acquisition of Pharmasset, we gained ownership of GS-7977, the most advanced, and to date the most potent, nucleotide analog that acts to inhibit the replication of HCV with limited safety or resistance concerns detected thus far. See the Risk Factor entitled “The public announcement of data from clinical studies evaluating GS-7977 in HCV-infected patients is likely to cause significant volatility in our stock price” on page 30.

Patents and Proprietary Rights

U.S. and European Patent Expiration

The following table shows the estimated expiration dates in the United States and Europe for the primary patents and for patents that may issue under pending applications for our Phase 3 product candidates:


Phase 3 Product Candidates	Patent Expiration⁽¹⁾
Product Candidates for the Treatment of HIV		U.S.		E.U.
Cobicistat		⁽²⁾		⁽²⁾
Elvitegravir		2023		2023
Integrase Single-Tablet Regimen “Quad”		2023	⁽³⁾	2023	⁽³⁾

Product Candidate for the Treatment of Liver Disease
GS-7977		2029		⁽²⁾

Product Candidate for the Treatment of Respiratory Diseases
Aztreonam for inhalation solution for the treatment of bronchiectasis		2021		2021

Product Candidate for the Treatment of Cardiovascular/Metabolic Diseases
Ranolazine for the treatment of incomplete revascularization post-percutaneous coronary intervention and the treatment of type II diabetes		2019		2019

⁽¹⁾	Does not reflect any possible patent term restoration or future supplementary protection certificates. Further, depending on the circumstances surrounding any regulatory approval of the product, there may be other patents that could have relevance to the product as finally approved.

⁽²⁾	Application is pending.

⁽³⁾	Based on the patent expiration date of elvitegravir, one of the components of Quad.

The following table shows the actual or estimated expiration dates in the United States and Europe for the primary patents and for patents that may issue under pending applications that cover the compounds in our marketed products:


Products	U.S. Patent Expiration			European Patent Expiration
Vistide		2010			2012	⁽¹⁾
Hepsera		2014			2016	⁽¹⁾
Letairis		2015			2015
AmBisome		2016			2008
Tamiflu		2016	⁽²⁾		2016
Macugen		2017			2017
Viread		2017	⁽³⁾		2018
Ranexa		2019			2023	⁽¹⁾
Lexiscan		2019			2020
Emtriva		2021			2016	⁽¹⁾
Truvada		2021			2018	⁽⁴⁾
Atripla		2021			2018	⁽⁵⁾
Cayston		2021			2021
Complera/Eviplera		2023	⁽⁶⁾		2022	⁽⁶⁾

⁽¹⁾	Supplementary Protection Certificate (SPC) protection has been obtained in certain European countries that confer an auxiliary form of patent exclusivity as indicated.

⁽²⁾	Pediatric exclusivity granted extending patent expiration to 2017.

⁽³⁾	Pediatric exclusivity granted extending patent expiration to 2018.

⁽⁴⁾	Based on the patent expiration date of Viread, one of the components of Truvada.

⁽⁵⁾	Based on the patent expiration date of Viread, one of the components of Atripla.

⁽⁶⁾	Based on the patent expiration date of Edurant, one of the components of Complera/Eviplera.

Patent Protection and Certain Challenges

Patents and other proprietary rights are very important to our business. If we have a properly designed and enforceable patent, it can be more difficult for our competitors to use our technology to create competitive products and more difficult for our competitors to obtain a patent that prevents us from using technology we create. As part of our business strategy, we actively seek patent protection both in the United States and internationally and file additional patent applications, when appropriate, to cover improvements in our compounds, products and technology. We also rely on trade secrets, internal know-how, technological innovations and agreements with third parties to develop, maintain and protect our competitive position. Our ability to be competitive will depend on the success of this strategy.

Patents covering the active pharmaceutical ingredients of Atripla, Truvada, Viread, Emtriva, Complera/Eviplera, Hepsera, Letairis, Vistide and Lexiscan are held by third parties. We acquired exclusive rights to these patents in the agreements we have with these parties. Patents do not cover ranolazine, the active ingredient of Ranexa. Instead, when it was discovered that only a sustained release formulation of ranolazine would achieve therapeutic plasma levels, patents were obtained on those formulations and the characteristic plasma levels they achieve. Patents do not cover the active ingredients in AmBisome. Instead, we hold patents to the liposomal formulations of this compound and also protect formulations through trade secrets. In addition, we do not have patent filings in China or certain other Asian countries covering all forms of adefovir dipivoxil, the active ingredient in Hepsera. Asia is a major market for therapies for hepatitis B, the indication for which Hepsera has been developed.

We may obtain patents for certain products many years before we obtain marketing approval for those products. Because patents have a limited life, which may begin to run prior to the commercial sale of the related product, the commercial value of the patent may be limited. However, we may be able to apply for patent term extensions. For example, extensions for the patents on many of our products have been granted in the United States and in a number of European countries, compensating in part for delays in obtaining marketing approval. Similar patent term extensions may be available for other products that we are developing, but we cannot be certain we will obtain them.

It is also very important that we do not infringe patents or proprietary rights of others and that we do not violate the agreements that grant proprietary rights to us. If we do infringe patents or violate these agreements, we could be prevented from developing or selling products or from using the processes covered by those patents or agreements, or we could be required to obtain a license from third parties to allow us to use their technology. We cannot be certain that, if required, we could obtain a license to any third-party technology or that we could obtain one at a reasonable cost. If we were not able to obtain a required license or alternative technologies, we may be unable to develop or commercialize some or all of our products, and our business could be adversely affected. For example, we are aware of a body of patents that may relate to our operation of Letairis Education and Access Program (LEAP), our restricted distribution program designed to support Letairis. In addition, we own patents that claim GS-7977 as a chemical entity and its metabolites. However, the existence of issued patents does not guarantee our right to practice the patented technology or commercialize the patented product. Third parties may have or obtain rights to patents which they may claim could be used to prevent or attempt to prevent us from commercializing the patented product candidates obtained from the Pharmasset acquisition. For example, we are aware of patents and patent applications owned by other parties that might be alleged to cover the use of GS-7977. If these other parties are successful in obtaining valid and enforceable patents, and establishing our infringement of those patents, we could be prevented from selling GS-7977 unless we were able to obtain a license under such patents. If any license is needed it may not be available on commercially reasonable terms or at all.

Further, Gilead (as successor to Pharmasset, Inc.) is a party to a collaboration agreement with Roche to develop PSI-6130 and its prodrugs for the treatment of chronic HCV infection. The collaborative research efforts under this agreement ended on December 31, 2006. Roche later asked Pharmasset to consider whether Roche may have contributed to the inventorship of GS-7977 and whether Pharmasset has complied with the confidentiality provisions of the collaboration agreement. Pharmasset advised us that it carefully considered the issues raised by Roche and that it believed any such issues are without merit. We have also considered these issues and reached the same conclusion. However, if Roche were to successfully assert that it contributed to the inventorship of GS-7977 and either independently develop GS-7977 or file an abbreviated new drug application (ANDA) to market GS-7977, Roche could at some point in the future market that product and begin competing against us prior to the expiration of our patents for GS-7977. Such marketing activity by Roche could materially reduce the revenues we expect to receive from the sale of GS-7977, which could adversely affect our results of operations.

Because patent applications are confidential for a period of time until a patent is issued, we may not know if our competitors have filed patent applications for technology covered by our pending applications or if we were the first to invent the technology that is the subject of our patent applications. Competitors may have filed patent applications or received patents and may obtain additional patents and proprietary rights that block or compete with our patents. If competitors file patent applications covering our technology, we may have to participate in interference proceedings or litigation to determine the right to a patent. Litigation and interference proceedings are expensive, such that, even if we are ultimately successful, our results of operations may be adversely affected by participation in such events.

Patents relating to pharmaceutical, biopharmaceutical and biotechnology products, compounds and processes such as those that cover our existing compounds, products and processes and those that we will likely file in the future, do not always provide complete or adequate protection. Future litigation or re-examination proceedings regarding the enforcement or validity of our existing patents or any future patents could invalidate our patents or substantially reduce their protection. For example, in 2007, the Public Patent Foundation filed requests for re-examination with the United States Patent and Trademark Office (PTO) challenging four of our patents related to tenofovir disoproxil fumarate, which is an active ingredient in Atripla, Truvada, Complera/Eviplera and Viread. The PTO granted these requests and issued non-final rejections for the four patents, which is a step common in a proceeding to initiate the re-examination process. In 2008, the PTO confirmed the patentability of all four patents.

Although we were successful in responding to the PTO actions in the instance above, similar organizations may still challenge our patents in U.S. and foreign jurisdictions. For example, in April 2008, the Brazilian Health Ministry, citing the U.S. patent re-examination proceedings as grounds for rejection, requested that the Brazilian patent authority issue a decision that is not supportive of our patent application for tenofovir disoproxil fumarate in Brazil. In August 2008, an examiner in the Brazilian patent authority issued a final rejection of our fumarate salt patent application, the only patent application for tenofovir disoproxil fumarate we have filed in Brazil. We then filed an appeal within the patent authority responding to the questions raised in the rejection. In July 2009, the Brazilian patent authority again rejected the application. This was the highest level of appeal available to us within the Brazilian patent authority. We have filed a civil action in Brazilian federal court to further appeal the action of the Brazilian patent authority. Because we do not currently have a patent in Brazil, in 2011 the Brazilian government purchased all of its supply of tenofovir disoproxil fumarate from generic manufacturers. As a result, we did not sell any of our HIV products in Brazil in 2011.

As another example, under Indian civil procedure, several parties filed oppositions to the grant of our patent applications covering tenofovir disoproxil and tenofovir disoproxil fumarate. In August 2009, the Indian Patent Office announced that it had decided these actions against us and would not therefore allow the patents to be granted. We have filed an appeal within the Indian Patent Office Intellectual Property Appellate Board on both of these applications. We cannot predict the outcome of these proceedings. If we are unsuccessful in our appeal of these decisions, any further appeals will have to be pursued in the Indian court system, and may ultimately prove unsuccessful. In the meantime, any competitor is able to sell generic tenofovir disoproxil fumarate in India. In

addition, if we are unsuccessful in appealing any further negative decisions by the Indian Patent Office in the Indian courts, these competitors would be able to continue to sell generic tenofovir disoproxil fumarate.

Our pending patent applications and the patent applications filed by our collaborative partners may not result in the issuance of any patents or may result in patents that do not provide adequate protection. As a result, we may not be able to prevent third parties from developing compounds or products that are closely related to those which we have developed or are developing. In addition, certain countries in Africa and Asia, including China, do not provide effective enforcement of our patents, and third-party manufacturers are able to sell generic versions of our products in those countries.

Abbreviated New Drug Applications Filed by Generic Manufacturers

As part of the approval process of some of our products, the FDA granted an exclusivity period during which other manufacturers’ applications for approval of generic versions of our product will not be granted. Generic manufacturers often wait to challenge the patents protecting products that have been granted exclusivity until one year prior to the end of the exclusivity period. From time to time, we have received notices from manufacturers indicating that they intend to import chemical intermediates possibly for use in making our products. Generic manufacturers have sought and may continue to seek FDA approval for a similar or identical drug through an ANDA, the application form typically used by manufacturers seeking approval of a generic drug.

For example, in November 2008, we received notice that Teva Pharmaceuticals (Teva) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Truvada. In the notice, Teva alleges that two of the patents associated with emtricitabine are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Truvada. In December 2008, we filed a lawsuit against Teva for infringement of the two emtricitabine patents. In March 2009, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Atripla. In the notice, Teva challenged the same two emtricitabine patents. In May 2009, we filed another lawsuit against Teva for infringement of the two emtricitabine patents, and this lawsuit was consolidated with the lawsuit filed in December 2008. In January 2010, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Viread. In the notice, Teva challenged four of the tenofovir disoproxil fumarate patents protecting Viread. In January 2010, we also received notices from Teva amending its ANDAs related to Atripla and Truvada. In the notice related to Truvada, Teva challenged four patents related to tenofovir disoproxil fumarate and two additional patents related to emtricitabine. In the notice related to Atripla, Teva challenged four patents related to tenofovir disoproxil fumarate, two additional patents related to emtricitabine and two patents related to efavirenz. In March 2010, we filed a lawsuit against Teva for infringement of the four Viread patents and two additional emtricitabine patents. In March 2010, BMS and Merck filed a lawsuit against Teva for infringement of the patents related to efavirenz.

In June 2010, we received notice that Lupin Limited (Lupin) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Ranexa. In the notice, Lupin alleges that ten of the patents associated with Ranexa are invalid, unenforceable and/or will not be infringed by Lupin’s manufacture, use or sale of a generic version of Ranexa. In July 2010, we filed a lawsuit against Lupin for infringement of our patents for Ranexa.

In August 2010, we received notice that Sigmapharm Labs (Sigmapharm) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Hepsera. In the notice, Sigmapharm alleges that both of the patents associated with Hepsera are invalid, unenforceable and/or will not be infringed by Sigmapharm’s manufacture, use or sale of a generic version of Hepsera. In September 2010, we filed a lawsuit against Sigmapharm for infringement of our patents for Hepsera. One of the patents challenged by Sigmapharm is also being challenged by Ranbaxy, Inc. (Ranbaxy) pursuant to a notice received in October 2010. The patent challenged by Ranbaxy expires in July 2018. We have the option of filing a lawsuit at any time if we believe that Ranbaxy is infringing our patent.

In February 2011, we received notice that Natco Pharma Limited (Natco) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Tamiflu. In the notice, Natco alleges that one of the patents associated with Tamiflu is invalid, unenforceable and/or will not be infringed by Natco’s manufacture, use or sale of a generic version of Tamiflu. In March 2011, we and Roche filed a lawsuit against Natco for infringement of the patent associated with Tamiflu.

In November 2011, we received notice that Teva submitted an Abbreviated New Drug Submission (ANDS) to the Canadian Ministry of Health requesting permission to manufacture and market a generic version of our Truvada product. In the notice, Teva alleges that three of the patents associated with Truvada are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Truvada. In January 2012, we filed a lawsuit against Teva seeking an order of prohibition against approval of this ANDS.

In December 2011, we received notice that Teva submitted an ANDS to the Canadian Ministry of Health requesting permission to manufacture and market a generic version of our Atripla product. In the notice, Teva alleges that three of our patents associated with Atripla and two of Merck’s patents associated with Atripla are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Atripla. In February 2012, we filed a lawsuit against Teva seeking an order of prohibition against approval of this ANDS.

We cannot predict the ultimate outcome of these actions, and we may spend significant resources enforcing and defending these patents. If we are unsuccessful in these lawsuits, some or all of our original claims in the patents may be narrowed or invalidated and the patent protection for Atripla, Truvada, Viread, Hepsera, Ranexa and Tamiflu in the United States or for Atripla and Truvada in Canada could be substantially shortened. Further, if all of the patents covering those products are invalidated, the FDA could approve the requests to manufacture a generic version of such products prior to the expiration date of those patents.

Trade Secrets

We also rely on unpatented trade secrets and improvements, unpatented internal know-how and technological innovation. In particular, a great deal of our liposomal manufacturing expertise, which is a key component of our liposomal technology, is not covered by patents but is instead protected as a trade secret. We protect these rights mainly through confidentiality agreements with our corporate partners, employees, consultants and vendors. These agreements provide that all confidential information developed or made known to an individual during the course of their relationship with us will be kept confidential and will not be used or disclosed to third parties except in specified circumstances. In the case of employees, the agreements provide that all inventions made by an individual while employed by us will be our exclusive property. We cannot be certain that these parties will comply with these confidentiality agreements, that we have adequate remedies for any breach or that our trade secrets will not otherwise become known or be independently discovered by our competitors. Under some of our R&D agreements, inventions become jointly owned by us and our corporate partner and in other cases become the exclusive property of one party. In certain circumstances, it can be difficult to determine who owns a particular invention and disputes could arise regarding those inventions.

Manufacturing and Raw Materials

Our manufacturing strategy is to contract with third parties to manufacture the majority of our active pharmaceutical ingredients and solid dose products. We also rely on our corporate partners to manufacture certain of our products. Additionally, we own or lease manufacturing facilities in San Dimas, California; Edmonton, Alberta, Canada; Cork, Ireland and Oceanside, California, where we manufacture certain products and active pharmaceutical ingredients for clinical and commercial uses.

Manufacturing of our Products

We contract with third parties to manufacture certain products for clinical and commercial purposes, including Atripla, Truvada, Viread, Hepsera, Complera/Eviplera, Emtriva, Ranexa and Vistide. We use multiple third-party contract manufacturers to manufacture tenofovir disoproxil fumarate, the active pharmaceutical ingredient in Viread and one of the active pharmaceutical ingredients in Atripla, Truvada and Complera/Eviplera; and emtricitabine, the active pharmaceutical ingredient in Emtriva and one of the active pharmaceutical ingredients in Atripla, Truvada and Complera/Eviplera. We rely on a single third-party manufacturer to manufacture the active pharmaceutical ingredients of Ranexa and Cayston. We are the exclusive manufacturer of the active pharmaceutical ingredients in Hepsera, Letairis and Vistide.

We also rely on third-party contract manufacturers to tablet or capsulate products. For example, we use multiple third-party contract manufacturers to tablet Atripla, Truvada, Viread, Hepsera, Complera/Eviplera and Ranexa. Emtriva encapsulation is also completed by third-party contract manufacturers. We rely on a single third-party supplier to manufacture Letairis tablets.

We also have manufacturing agreements with many of our corporate partners. Roche, by itself and through third parties, is responsible for the manufacturing of Tamiflu. Under our agreement with Roche, through a joint manufacturing committee composed of representatives from Roche and us, we have the opportunity to review Roche’s existing manufacturing capacity for Tamiflu and global plans for manufacturing Tamiflu. Astellas US LLC, our corporate partner for Lexiscan in the United States, is responsible for the commercial manufacture and supply of product in the United States and is dependent on a single supplier for the active pharmaceutical ingredient of Lexiscan. PARI Pharma GmbH is responsible for the manufacturing of the device required to administer Cayston to the lungs of patients. This device is made by a single supplier at a single site.

For our future products, we continue to develop additional manufacturing capabilities and establish additional third-party suppliers to manufacture sufficient quantities of our product candidates to undertake clinical trials and to manufacture sufficient quantities of any product that is approved for commercial sale. If we are unable to develop manufacturing capabilities internally or contract for large scale manufacturing with third parties on acceptable terms for our future products, our ability to conduct large scale clinical trials and meet customer demand for commercial products will be adversely affected.

Our Manufacturing Facilities

At our San Dimas facility, we manufacture, fill and package products. We currently manufacture Cayston exclusively at our San Dimas, California manufacturing facility. Due to unexpected delays both in qualifying two new external sites and with expanding Cayston manufacturing in San Dimas, we cannot supply enough Cayston to fulfill our projected demand. In February 2012, we suspended access for patients with new prescriptions for Cayston subject to certain exceptions where specific medical need exists. Patients may use other alternative treatment options until we are able to resolve the supply shortage. As a result of our inability to manufacture sufficient Cayston to meet demand, the amount of revenues we expect to receive from the sale of Cayston will be reduced.

We are the single supplier of AmBisome at our San Dimas facility. We depend on a single supplier for high quality cholesterol, which is used in the manufacture of AmBisome. We fill and finish Macugen exclusively at our facilities in San Dimas under our manufacturing agreements with Eyetech and Pfizer. Eyetech currently provides us with pegaptanib sodium, the active pharmaceutical ingredient in Macugen. We also fill and package solid dosage form products, including Atripla, Truvada, Viread, Complera/Eviplera, Emtriva and Ranexa, in their finished forms and label Hepsera at our facilities in San Dimas. In the event of a disaster, including an earthquake, equipment failure or other difficulty, we may be unable to replace this manufacturing capacity in a timely manner and may be unable to manufacture AmBisome and Macugen to meet market needs.

We fill and package drug product for Atripla, Truvada, Viread and Cayston in their finished forms and label Hepsera and Emtriva at our facilities in Cork, Ireland. We also perform quality control testing, final labeling and

packaging of AmBisome and final release of many of our products for the European Union and elsewhere at this facility. We utilize our Cork, Ireland facility primarily for solid dose tablet manufacturing of certain of our antiviral products, as well as product packaging activities. We distribute our products to the European Union and other international markets from our Dublin, Ireland site.

At our Edmonton facility, we carry out process research and scale-up of our clinical development candidates, manufacture active pharmaceutical ingredients for both investigational and commercial products and conduct chemical development activities to improve existing commercial manufacturing processes. We also manufacture the active pharmaceutical ingredients in Hepsera, Letairis and Vistide exclusively at our Edmonton site, although another supplier is qualified to make the active pharmaceutical ingredient in Letairis.

Our Oceanside facility, acquired in 2011, is designed and equipped to produce biologic compounds for toxicological, Phase 1 and Phase 2 clinical studies. We use the facility for the process development and manufacture of GS-6624 an investigational monoclonal antibody candidate in development for treatment of certain cancers and for fibrotic diseases, and another antibody which is currently in preclinical testing.

Third-party Manufacturers

Our third-party manufacturers and our corporate partners are independent entities who are subject to their own unique operational and financial risks which are out of our control. If we or any of our third-party manufacturers or our corporate partners fail to perform as required, this could impair our ability to deliver our products on a timely basis or receive royalties or cause delays in our clinical trials and applications for regulatory approval. To the extent these risks materialize and affect their performance obligations to us, our financial results may be adversely affected.

We believe the technology we use to manufacture our products is proprietary. For products manufactured by our third-party contract manufacturers, we have disclosed all necessary aspects of this technology to enable them to manufacture the products for us. We have agreements with these third-party manufacturers that are intended to restrict these manufacturers from using or revealing this technology, but we cannot be certain that these third-party manufacturers will comply with these restrictions. In addition, these third-party manufacturers could develop their own technology related to the work they perform for us that we may need to manufacture our products. We could be required to enter into additional agreements with these third-party manufacturers if we want to use that technology ourselves or allow another manufacturer to use that technology. The third-party manufacturer could refuse to allow us to use their technology or could demand terms to use their technology that are not acceptable to us.

Regulation of Manufacturing Process

The manufacturing process for pharmaceutical products is highly regulated and regulators may shut down manufacturing facilities that they believe do not comply with regulations. We, our third-party manufacturers and our corporate partners are subject to current Good Manufacturing Practices, which are extensive regulations governing manufacturing processes, stability testing, record keeping and quality standards as defined by the FDA and the European Medicines Agency. Similar regulations are in effect in other countries.

Our manufacturing operations are subject to routine inspections by regulatory agencies. For example, in January and February 2010, the FDA conducted a routine inspection of our San Dimas, California, manufacturing and distribution facility, where we manufacture AmBisome and Cayston, fill and finish Macugen, and package solid dosage form products. At the conclusion of that inspection, the FDA issued Form 483 Inspectional Observations stating concerns over: the maintenance of aseptic processing conditions in the manufacturing suite for our AmBisome product; environmental maintenance issues in the San Dimas warehousing facility; batch sampling; and the timeliness of completion of annual product quality reports. On September 24, 2010, our San Dimas manufacturing facility received a Warning Letter from the FDA further

detailing the FDA’s concerns over the AmBisome manufacturing environment, including control systems and monitoring, procedures to prevent microbiological contamination and preventative cleaning and equipment maintenance. Referencing certain Viread lots, the letter also stated concerns connected with quality procedures, controls and investigation procedures, and a generalized concern over the effectiveness of the San Dimas quality unit in carrying out its responsibilities. In November and December 2010, the FDA re-inspected the San Dimas facility. The re-inspection closed with no additional Form 483 observations. In August 2011, the FDA notified us that we resolved all issues raised by the FDA in its Warning Letter.

Access to Supplies and Materials

We need access to certain supplies and products to manufacture our products. If delivery of material from our suppliers were interrupted for any reason or if we are unable to purchase sufficient quantities of raw materials used to manufacture our products, we may be unable to ship certain of our products for commercial supply or to supply our product candidates in development for clinical trials. For example, a significant portion of the raw materials and intermediates used to manufacture our HIV products (Atripla, Truvada, Viread, Emtriva and Complera/Eviplera) are supplied by Chinese-based companies. As a result, an international trade dispute between China and the United States or any other actions by the Chinese government that would limit or prevent Chinese companies from supplying these materials would adversely affect our ability to manufacture and supply our HIV products to meet market needs and have a material and adverse effect on our operating results.

Seasonal Operations and Backlog

Our worldwide product sales do not reflect any significant degree of seasonality. However, our royalty revenues, which represented approximately 3% of our total revenues in 2011 and consisted primarily of Tamiflu royalties, are affected by seasonality. Royalty revenue that we recognize from Roche’s sales of Tamiflu can be impacted by the severity of flu seasons and product delivery in response to the influenza pandemics.

For the most part, we operate in markets characterized by short lead times and the absence of significant backlogs. We do not believe that backlog information is material to our business as a whole.

Government Regulation

Our operations and activities are subject to extensive regulation by numerous government authorities in the United States and other countries. In the United States, drugs are subject to rigorous FDA regulation. The Federal Food, Drug and Cosmetic Act and other federal and state statutes and regulations govern the testing, manufacture, safety, efficacy, labeling, storage, record keeping, approval, advertising and promotion of our products. As a result of these regulations, product development and product approval processes are very expensive and time consuming.

The FDA must approve a drug before it can be sold in the United States. The general process for this approval is as follows:

Preclinical Testing

Before we can test a drug candidate in humans, we must study the drug in laboratory experiments and in animals to generate data to support the drug candidate’s potential benefits and safety. We submit this data to the FDA in an investigational new drug (IND) application seeking its approval to test the compound in humans.

Clinical Trials

If the FDA accepts the investigational new drug application, the drug candidate can then be studied in human clinical trials to determine if the drug candidate is safe and effective. These clinical trials involve three separate phases that often overlap, can take many years and are very expensive. These three phases, which are subject to considerable regulation, are as follows:

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Phase 1. The drug candidate is given to a small number of healthy human control subjects or patients suffering from the indicated disease, to test for safety, dose tolerance, pharmacokinetics, metabolism, distribution and excretion.

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Phase 2. The drug candidate is given to a limited patient population to determine the effect of the drug candidate in treating the disease, the best dose of the drug candidate, and the possible side effects and safety risks of the drug candidate. It is not uncommon for a drug candidate that appears promising in Phase 1 clinical trials to fail in the more rigorous Phase 2 clinical trials.

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Phase 3. If a drug candidate appears to be effective and safe in Phase 2 clinical trials, Phase 3 clinical trials are commenced to confirm those results. Phase 3 clinical trials are conducted over a longer term, involve a significantly larger population, are conducted at numerous sites in different geographic regions and are carefully designed to provide reliable and conclusive data regarding the safety and benefits of a drug candidate. It is not uncommon for a drug candidate that appears promising in Phase 2 clinical trials to fail in the more rigorous and extensive Phase 3 clinical trials.

FDA Approval Process

When we believe that the data from the Phase 3 clinical trials show an adequate level of safety and efficacy, we submit the appropriate filing, usually in the form of a new drug application (NDA) or supplemental NDA, with the FDA seeking approval to sell the drug candidate for a particular use. The FDA may hold a public hearing where an independent advisory committee of expert advisors asks additional questions and makes recommendations regarding the drug candidate. This committee makes a recommendation to the FDA that is not binding but is generally followed by the FDA. If the FDA agrees that the compound has met the required level of safety and efficacy for a particular use, it will allow us to sell the drug candidate in the United States for that use. It is not unusual, however, for the FDA to reject an application because it believes that the drug candidate is not safe enough or efficacious enough or because it does not believe that the data submitted is reliable or conclusive.

At any point in this process, the development of a drug candidate can be stopped for a number of reasons including safety concerns and lack of treatment benefit. We cannot be certain that any clinical trials that we are currently conducting or any that we conduct in the future will be completed successfully or within any specified time period. We may choose, or the FDA may require us, to delay or suspend our clinical trials at any time if it appears that the patients are being exposed to an unacceptable health risk or if the drug candidate does not appear to have sufficient treatment benefit.

The FDA may also require Phase 4 non-registrational studies to explore scientific questions to further characterize safety and efficacy during commercial use of our drug. The FDA may also require us to provide additional data or information, improve our manufacturing processes, procedures or facilities or may require extensive surveillance to monitor the safety or benefits of our product candidates if it determines that our filing does not contain adequate evidence of the safety and benefits of the drug. In addition, even if the FDA approves a drug, it could limit the uses of the drug. The FDA can withdraw approvals if it does not believe that we are complying with regulatory standards or if problems are uncovered or occur after approval.

In addition to obtaining FDA approval for each drug, we obtain FDA approval of the manufacturing facilities for any drug we sell, including those of companies who manufacture our drugs for us. All of these facilities are subject to periodic inspections by the FDA. The FDA must also approve foreign establishments that manufacture products to be sold in the United States and these facilities are subject to periodic regulatory

inspection. Our manufacturing facilities located in California, including our San Dimas facilities, also must be licensed by the State of California in compliance with local regulatory requirements. Our manufacturing facilities located in Canada, including our Edmonton, Alberta facility, and our facilities located near Dublin and in Cork, Ireland, also must obtain local licenses and permits in compliance with local regulatory requirements.

Drugs that treat serious or life threatening diseases and conditions that are not adequately addressed by existing drugs, and for which the development program is designed to address the unmet medical need, may be designated as fast track candidates by the FDA and may be eligible for accelerated and priority review. Drugs for the treatment of HIV infection that are designated for use under the U.S. President’s Emergency Plan for AIDS Relief may also qualify for an expedited or priority review. Atripla, Truvada, Viread and Complera received accelerated approval and priority reviews. Drugs receiving accelerated approval must be monitored in post-marketing clinical trials in order to confirm the safety and benefits of the drug.

Drugs are also subject to extensive regulation outside of the United States. In the European Union, there is a centralized approval procedure that authorizes marketing of a product in all countries of the European Union (which includes most major countries in Europe). If this centralized approval procedure is not used, approval in one country of the European Union can be used to obtain approval in another country of the European Union under one of two simplified application processes: the mutual recognition procedure or the decentralized procedure, both of which rely on the principle of mutual recognition. After receiving regulatory approval through any of the European registration procedures, separate pricing and reimbursement approvals are also required in most countries.

Pricing and Reimbursement

Successful commercialization of our products depends, in part, on the availability of governmental and third-party payer reimbursement for the cost of such products and related treatments. Government health administration authorities, private health insurers and other organizations generally provide reimbursement. In the United States, the European Union and other significant or potentially significant markets for our products and product candidates, government authorities and third-party payers are increasingly attempting to limit or regulate the price of medical products and services, particularly for new and innovative products and therapies, which has resulted in lower average selling prices.

A significant portion of our sales of the majority of our products are subject to significant discounts from list price and rebate obligations. In the United States, state AIDS Drug Assistance Programs (ADAPs), which purchase a significant portion of our HIV products, rely on federal, supplemental federal and state funding to help fund purchases of our products. Given the current economic downturn, we have experienced a shift in our payer mix as patients previously covered by private insurance move to public reimbursement programs that require rebates or discounts from us or as patients previously covered by one public reimbursement program move to another public reimbursement program that requires greater rebates or discounts from us. As a result of this shift, revenue growth may be lower than prescription growth. If federal and state funds are not available in amounts sufficient to support the number of patients that rely on ADAPs, sales of our HIV products could be negatively impacted which would reduce our revenues. For example, during the first quarter of 2011, the state budget crisis in Florida led to a temporary movement of patients who were previously covered by Florida’s ADAP into industry-supported patient assistance programs. Due to the insufficiency of federal and state funds and as many states have reduced eligibility criteria, we have also seen and may continue to see an increase in the number of patients on state ADAP wait lists. Until these patients are enrolled in ADAP, they generally receive product from industry-supported patient assistance programs or are unable to access treatment. The increased emphasis on managed healthcare in the United States and on country and regional pricing and reimbursement controls in the European Union will put additional pressure on product pricing, reimbursement and usage, which may adversely affect our product sales and profitability. These pressures can arise from rules and practices of managed care groups, judicial decisions and governmental laws and regulations related to Medicare, Medicaid and healthcare reform, pharmaceutical reimbursement policies and pricing in general.

In Europe, the success of our commercialized products, and any other product candidates we may develop, will depend largely on obtaining and maintaining government reimbursement, because in many European countries patients are unlikely to use prescription drugs that are not reimbursed by their governments. In addition, negotiating prices with governmental authorities can delay commercialization by 12 months or more. Reimbursement policies may adversely affect our ability to sell our products on a profitable basis. In many international markets, governments control the prices of prescription pharmaceuticals, including through the implementation of reference pricing, price cuts, rebates, revenue-related taxes and profit control, and they expect prices of prescription pharmaceuticals to decline over the life of the product or as volumes increase.

Recently, many countries in the European Union have increased the amount of discounts required on our products, and these efforts could continue as countries attempt to manage healthcare expenditures, especially in light of the severe fiscal and debt crises experienced by many countries in the European Union. For example, in June 2010, Spain imposed an incremental discount on all branded drugs and in August 2010, Germany increased the rebate on prescription pharmaceuticals. As generic drugs come to market, we may face price decreases for our products in some countries in the European Union.

Government agencies also issue regulations and guidelines directly applicable to us and to our products. In addition, from time to time, professional societies, practice management groups, private health/science foundations and organizations publish guidelines or recommendations directed to certain health care and patient communities. Such recommendations and guidelines may relate to such matters as product usage, dosage, route of administration, and use of related or competing therapies and can consequently result in increased or decreased usage of our products. For example, recent HIV treatment guidelines in the United States and abroad have endorsed earlier diagnosis and treatment.

United States Healthcare Reform

In March 2010, healthcare reform legislation was adopted in the United States. As a result, we are required to further rebate or discount products reimbursed or paid for by various public payers, including Medicaid and other entities eligible to purchase discounted products through the 340B Drug Pricing Program under the Public Health Service Act, such as ADAPs. The discounts, rebates and fees in the legislation that impacted us include:

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our minimum base rebate amount owed to Medicaid on products reimbursed by Medicaid has been increased by 8%, and the discounts or rebates we owe to ADAPs and other Public Health Service entities which reimburse or purchase our products have also been increased by 8%;

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we are required to extend rebates to patients receiving our products through Medicaid managed care organizations;

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we are required to provide a 50% discount on products sold to patients while they are in the Medicare Part D “donut hole;” and

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we, along with other pharmaceutical manufacturers of branded drug products, are required to pay a portion of a new industry fee (also known as the pharmaceutical excise tax), of $2.5 billion for 2011, calculated based on select government sales during the 2009 calendar year as a percentage of total industry government sales.

The amount of the industry fee imposed on the pharmaceutical industry as a whole will increase to $2.8 billion in 2012, with additional increases over the next several years to a peak of $4.1 billion per year in 2018, and then decrease to $2.8 billion in 2019 and thereafter. As the amount of the industry fee increases, our product sales increase and drug patents expire on major drugs, such as Lipitor, we expect our portion of the excise tax to increase as well. We estimate the 2012 impact of the pharmaceutical excise tax to be approximately $80-$100 million, compared to approximately $50 million in 2011. The excise tax is not tax deductible.

Further, even though not addressed in the healthcare reform legislation, discussions continue at the federal level on legislation that would either allow or require the federal government to directly negotiate price concessions from pharmaceutical manufacturers or set minimum requirements for Medicare Part D pricing.

In addition, state Medicaid programs could request additional supplemental rebates on our products as a result of the increase in the federal base Medicaid rebate. Private insurers could also use the enactment of these increased rebates to exert pricing pressure on our products, and to the extent that private insurers or managed care programs follow Medicaid coverage and payment developments, the adverse effects may be magnified by private insurers adopting lower payment schedules.

Health Care Fraud and Abuse Laws and Anti-Bribery Laws

We are subject to various federal and state laws pertaining to health care “fraud and abuse,” including anti-kickback laws and false claims laws. Anti-kickback laws make it illegal for a prescription drug manufacturer to solicit, offer, receive or pay any remuneration in exchange for, or to induce, the referral of business, including the purchase or prescription of a particular drug. Due to the breadth of the statutory provisions and the increasing attention being given to them by law enforcement authorities, it is possible that certain of our practices may be challenged under anti-kickback or similar laws. False claims laws prohibit anyone from knowingly and willingly presenting, or causing to be presented for payment to third-party payers (including Medicare and Medicaid), claims for reimbursed drugs or services that are false or fraudulent, claims for items or services not provided as claimed or claims for medically unnecessary items or services. Our sales and marketing activities may be subject to scrutiny under these laws. In addition, the U.S. Foreign Corrupt Practices Act and similar worldwide anti-bribery laws generally prohibit companies and their intermediaries from making improper payments to non-U.S. officials for the purpose of obtaining or retaining business. Our policies mandate compliance with these anti-bribery laws. We operate in parts of the world that have experienced governmental corruption to some degree and in certain circumstances, strict compliance with anti-bribery laws may conflict with local customs and practices or may require us to interact with doctors and hospitals, some of which may be state controlled, in a manner that is different than in the U.S. Despite our training and compliance program, our internal control policies and procedures may not protect us from reckless or criminal acts committed by our employees or agents. Violations of fraud and abuse laws or anti-bribery laws may be punishable by criminal and/or civil sanctions, including fines and civil monetary penalties, as well as the possibility of exclusion from federal health care programs (including Medicare and Medicaid). If the government were to allege against or convict us of violating these laws, there could be a disruption on our business and material adverse effect on our results of operations.

Compulsory Licenses

In a number of developing countries, government officials and other interested groups have suggested that pharmaceutical companies should make drugs for HIV infection available at low cost. Alternatively, governments in those developing countries could require that we grant compulsory licenses to allow competitors to manufacture and sell their own versions of our products, thereby reducing our product sales. For example, in the past, certain offices of the government of Brazil have expressed concern over the affordability of our HIV products and declared that they were considering issuing compulsory licenses to permit the manufacture of otherwise patented products for HIV infection, including Viread. In July 2009, the Brazilian patent authority rejected our patent application for tenofovir disoproxil fumarate, the active pharmaceutical ingredient in Viread. This was the highest level of appeal available to us within the Brazilian patent authority. We have filed a civil action in Brazilian federal court to further appeal the action of the Brazilian patent authority. Because we do not currently have a patent in Brazil, in 2011 the Brazilian government purchased all of its supply of tenofovir disoproxil fumarate from generic manufacturers. As a result, we did not sell any of our HIV products in Brazil in 2011.

sublicense to India’s Hetero Drugs Limited for India and certain developing countries. Should one or more compulsory licenses be issued permitting generic manufacturing to override our Tamiflu patents, or should Roche issue additional voluntary licenses to permit third-party manufacturing of Tamiflu, those developments could reduce royalties we receive from Roche’s sales of Tamiflu. Certain countries do not permit enforcement of our patents, and third-party manufacturers are able to sell generic versions of our products in those countries. Compulsory licenses or sales of generic versions of our products could significantly reduce our sales and adversely affect our results of operations, particularly if generic versions of our products are imported into territories where we have existing commercial sales.

Employees

As of January 31, 2012, we had approximately 4,500 full-time employees. We believe we have good relations with our employees.

Environment, Health and Safety

We are voluntarily assessing and publicly reporting our greenhouse gas emissions and water usage, and have begun to take action to reduce such emissions and usage. For example we have established employee commuter programs, evaluated the energy efficiency of our buildings and installed low-flow water fixtures. Various laws and regulations have been implemented or are under consideration to mitigate the effects of climate change caused by greenhouse gas emissions. For example, the California Air Resources Board is in the process of drafting regulations to meet state emissions targets. Based on current information and subject to the finalization of the proposed regulations, we believe that our primary risk related to climate change is the risk of increased energy costs. However, because we are not an energy intensive business, we do not anticipate being subject to a cap and trade system or any other mitigation measures that would likely be material to our capital expenditures, results of operations or competitive position.

We are also subject to other federal, state and local regulations regarding workplace safety and protection of the environment. We use hazardous materials, chemicals, viruses and various radioactive compounds in our R&D activities and cannot eliminate the risk of accidental contamination or injury from these materials. Certain misuse or accidents involving these materials could lead to significant litigation, fines and penalties. We have implemented proactive programs to reduce and minimize the risk of hazardous materials incidents.

Other Information

We are subject to the information requirements of the Exchange Act. Therefore, we file periodic reports, proxy statements and other information with the SEC. Such reports, proxy statements and other information may be obtained by visiting the Public Reference Room of the SEC at 100 F Street, NE, Washington, D.C. 20549 or by calling the SEC at 1-800-SEC-0330, by sending an electronic message to the SEC at publicinfo@sec.gov or by sending a fax to the SEC at 1-202-777-1027. In addition, the SEC maintains a website (www.sec.gov) that contains reports, proxy and information statements, and other information regarding issuers that file electronically.

The mailing address of our headquarters is 333 Lakeside Drive, Foster City, California 94404, and our telephone number at that location is 650-574-3000. Our website is www.gilead.com. Through a link on the “Investors” section of our website (under “SEC Filings” in the “Financial Information” section), we make available the following filings as soon as reasonably practicable after they are electronically filed with or furnished to the SEC: our Annual Reports on Form 10-K; Quarterly Reports on Form 10-Q; Current Reports on Form 8-K; and any amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act. All such filings are available free of charge upon request.

ITEM 1A.

RISK FACTORS

In evaluating our business, you should carefully consider the following risks in addition to the other information in this Annual Report on Form 10-K. A manifestation of any of the following risks could materially and adversely affect our business, results of operations and financial condition. We note these factors for investors as permitted by the Private Securities Litigation Reform Act of 1995. It is not possible to predict or identify all such factors and, therefore, you should not consider the following risks to be a complete statement of all the potential risks or uncertainties that we face.

The public announcement of data from clinical studies evaluating GS-7977 in HCV-infected patients is likely to cause significant volatility in our stock price.

During 2012, we expect to receive a significant amount of data from clinical trials evaluating GS-7977, an investigational nucleotide analog we acquired through our purchase of Pharmasset, in HCV-infected individuals across genotypes. We are currently conducting Phase 2 studies in genotype 1 infected HCV patients to determine the efficacy of GS-7977 plus ribavirin in this population. Results from these studies will be available over the next several months. We expect the first data evaluating GS-7977 plus ribavirin for 12 weeks in genotype 1 treatment-naïve patients from an arm of the QUANTUM study with 25 patients will be available at the end of the first quarter of 2012. We expect that this will be followed in the second quarter by data from an arm of our ELECTRON study involving 25 treatment-naïve patients treated for 12 weeks and, early in the third quarter, data on GS-7977 and ribavirin treatment for 24 weeks from an arm of the QUANTUM study will become available.

On February 17, 2012, we announced that the majority of HCV genotype 1 patients with a prior “null” response to an interferon-containing regimen enrolled in our ongoing ELECTRON study experienced viral relapse within four weeks of completing 12 weeks of treatment with GS-7977 plus ribavirin. Ten patients were randomized to this arm of the ELECTRON study and data were available for eight of the ten patients at the time of the announcement. Among these eight patients, six experienced viral relapse. Two patients had not relapsed; however, they had only reached the two week post-treatment time point. These data indicate that treatment of genotype 1 patients classified as null responders with GS-7977 plus ribavirin for 12 weeks will not be sufficient to cure their disease.

In addition to the Phase 2 studies described above, we recently began enrolling patients in a Phase 3 study evaluating GS-7977 and ribavirin in genotype 2 and 3 infected patients. A second Phase 3 study of genotype 2 and 3 patients is scheduled to begin enrolling in the next few weeks.

If data from any of the Phase 2 or 3 studies indicate that a smaller than anticipated number of patients achieved a sustained viral response at 4, 12 or 24 weeks post-treatment, our stock price may decline significantly. Such results could also delay the approval of GS-7977 for the treatment of genotype 1, 2 and/or 3 patients, which could delay and/or reduce revenues expected from the sale of GS-7977. Developing drugs for the treatment of HCV is a competitive field and a significant number of drugs are under development. Depending on the length of any delay in our development of GS-7977, other companies who are developing competitive compounds in HCV may be able to progress their development timelines and potentially bring compounds to market before GS-7977 or shortly thereafter.

A substantial portion of our revenues is derived from sales of our HIV products, particularly Atripla and Truvada. If we are unable to maintain or continue increasing sales of these products, our results of operations may be adversely affected.

We are currently dependent on sales of our products for the treatment of HIV infection, particularly Atripla and Truvada, to support our existing operations. Our HIV products contain tenofovir disoproxil fumarate and/or emtricitabine, which belong to the nucleoside class of antiviral therapeutics. Were the treatment paradigm for HIV to change, causing nucleoside-based therapeutics to fall out of favor, or if we were unable to maintain or continue increasing our HIV product sales, our results of operations would likely suffer and we would likely need

to scale back our operations, including our spending on research and development (R&D) efforts. For the year ended December 31, 2011, Atripla and Truvada product sales together were $6.10 billion, or 73% of our total revenues. We may not be able to sustain or increase the growth rate of sales of our HIV products, especially Atripla and Truvada, for any number of reasons including, but not limited to, the following:

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As our HIV products are used over a longer period of time in many patients and in combination with other products, and additional studies are conducted, new issues with respect to safety, resistance and interactions with other drugs may arise, which could cause us to provide additional warnings or contraindications on our labels, narrow our approved indications or halt sales of a product, each of which could reduce our revenues.

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As our HIV products mature, private insurers and government payers often reduce the amount they will reimburse patients for these products, which increases pressure on us to reduce prices.

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A large part of the market for our HIV products consists of patients who are already taking other HIV drugs. If we are not successful in encouraging physicians to change patients’ regimens to include our HIV products, the sales of our HIV products will be limited.

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As generic HIV products are introduced into major markets, our ability to maintain pricing and market share may be affected.

If we fail to commercialize new products or expand the indications for existing products, our prospects for future revenues may be adversely affected.

If we do not introduce new products to market or increase sales of our existing products, we will not be able to increase or maintain our total revenues and continue to expand our R&D efforts. Drug development is inherently risky and many product candidates fail during the drug development process. For example, in January 2011, we announced our decision to terminate our Phase 3 clinical trial of ambrisentan in patients with idiopathic pulmonary fibrosis (IPF). In April 2011, we announced our decision to terminate our Phase 3 clinical trial of aztreonam for inhalation solution for the treatment of cystic fibrosis (CF) in patients with Burkholderia spp. In addition, our marketing applications for our single-tablet “Quad” regimen of elvitegravir, cobicistat, tenofovir disoproxil fumarate and emtricitabine, for the treatment of HIV in treatment-naïve patients may not be approved by the FDA or European Medicines Agency. Further, even if marketing approval is granted, there may be significant limitations on its use. Further, we may be unable to file our marketing applications for elvitegravir and cobicistat in the currently anticipated timelines and marketing approval for the products may not be granted.

Our results of operations will be adversely affected by current and potential future healthcare reforms.

Legislative and regulatory changes to government prescription drug procurement and reimbursement programs occur relatively frequently in the United States and foreign jurisdictions. In March 2010, healthcare reform legislation was adopted in the United States. As a result, we are required to further rebate or discount products reimbursed or paid for by various public payers, including Medicaid and other entities eligible to purchase discounted products through the 340B Drug Pricing Program under the Public Health Service Act, such as AIDS Drug Assistance Programs (ADAPs). The discounts, rebates and fees in the legislation that impacted us include:

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we are required to extend rebates to patients receiving our products through Medicaid managed care organizations;

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we are required to provide a 50% discount on products sold to patients while they are in the Medicare Part D “donut hole;” and

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we, along with other pharmaceutical manufacturers of branded drug products, are required to pay a portion of a new industry fee (also known as the pharmaceutical excise tax) of $2.5 billion for 2011, calculated based on select government sales during the 2009 calendar year as a percentage of total industry government sales.

Our existing products are subject to reimbursement from government agencies and other third parties. Pharmaceutical pricing and reimbursement pressures may reduce profitability.

A significant portion of our sales of the majority of our products are subject to significant discounts from list price and rebate obligations. In the United States, state ADAPs, which purchase a significant portion of our HIV products, rely on federal, supplemental federal and state funding to help fund purchases of our products. Given the current economic downturn, we have experienced a shift in our payer mix as patients previously covered by private insurance move to public reimbursement programs that require rebates or discounts from us or as patients previously covered by one public reimbursement program move to another public reimbursement program that requires greater rebates or discounts from us. As a result of this shift, revenue growth may be lower than prescription growth. If federal and state funds are not available in amounts sufficient to support the number of patients that rely on ADAPs, sales of our HIV products could be negatively impacted which would reduce our revenues. For example, during the first quarter of 2011, the state budget crisis in Florida led to a temporary movement of patients who were previously covered by Florida’s ADAP into industry-supported patient assistance programs. Due to the insufficiency of federal and state funds and as many states have reduced eligibility criteria, we have also seen and may continue to see an increase in the number of patients on state ADAP wait lists. Until these patients are enrolled in ADAP, they generally receive product from industry-supported patient assistance programs or are unable to access treatment. The increased emphasis on managed healthcare in the United States and on country and regional pricing and reimbursement controls in the European Union will put additional pressure on product pricing, reimbursement and usage, which may adversely affect our product sales and profitability. These pressures can arise from rules and practices of managed care groups, judicial decisions and governmental laws and regulations related to Medicare, Medicaid and healthcare reform, pharmaceutical reimbursement policies and pricing in general.

Approximately 44% of our product sales occur outside the United States, and currency fluctuations and hedging expenses may cause our earnings to fluctuate, which could adversely affect our stock price.

Because a significant percentage of our product sales are denominated in foreign currencies, primarily the Euro, we face exposure to adverse movements in foreign currency exchange rates. When the U.S. dollar strengthens against these foreign currencies, the relative value of sales made in the respective foreign currency decreases. Conversely, when the U.S. dollar weakens against these currencies, the relative value of such sales increases. Overall, we are a net receiver of foreign currencies and, therefore, benefit from a weaker U.S. dollar and are adversely affected by a stronger U.S. dollar relative to those foreign currencies in which we transact significant amounts of business.

We use foreign currency exchange forward and option contracts to hedge a percentage of our forecasted international sales, primarily those denominated in the Euro. We also hedge certain monetary assets and liabilities denominated in foreign currencies, which reduces but does not eliminate our exposure to currency fluctuations between the date a transaction is recorded and the date that cash is collected or paid. We cannot predict future fluctuations in the foreign currency exchange rate of the U.S. dollar. If the U.S. dollar appreciates significantly against certain currencies and our hedging program does not sufficiently offset the effects of such appreciation, our results of operations will be adversely affected and our stock price may decline.

Additionally, the expenses that we recognize in relation to our hedging activities can also cause our earnings to fluctuate. The level of hedging expenses that we recognize in a particular period is impacted by the changes in interest rate spreads between the foreign currencies that we hedge and the U.S. dollar.

Our inability to accurately estimate demand for our products, as well as sales fluctuations as a result of inventory levels held by wholesalers, pharmacies and non-retail customers make it difficult for us to accurately forecast sales and may cause our earnings to fluctuate, which could adversely affect our financial results and our stock price.

In 2011, approximately 79% of our product sales in the United States were to three wholesalers, Cardinal Health, Inc., McKesson Corp. and AmerisourceBergen Corp. The U.S. wholesalers with whom we have entered into inventory management agreements make estimates to determine end user demand and may not be completely effective in matching their inventory levels to actual end user demand. As a result, changes in inventory levels held by those wholesalers can cause our operating results to fluctuate unexpectedly if our sales to these wholesalers do not match end user demand. In addition, inventory is held at retail pharmacies and other non-wholesale locations with whom we have no inventory management agreements and no control over buying patterns. Adverse changes in economic conditions or other factors may cause retail pharmacies to reduce their

inventories of our products, which would reduce their orders from wholesalers and, consequently, the wholesalers’ orders from us, even if end user demand has not changed. For example, during the fourth quarter of 2010, our wholesalers increased their inventory levels for our antiviral products. In the first quarter of 2011, our wholesalers drew down on their inventory such that inventory levels for our antiviral products moved to the lower end of the contractual boundaries set by our inventory management agreements. As inventory in the distribution channel fluctuates from quarter to quarter, we may continue to see fluctuations in our earnings and a mismatch between prescription demand for our products and our revenues.

In addition, the non-retail sector in the United States, which includes government institutions, including state ADAPs, correctional facilities and large health maintenance organizations, tends to be even less consistent in terms of buying patterns and often causes quarter over quarter fluctuations that do not necessarily mirror patient demand. For example, in the first quarter of 2011, non-retail purchases, driven by certain state ADAPs, were lower as a percentage of their federal ADAP fiscal year purchases compared to the first quarters of 2009 and 2010. We believe this decrease was driven by uncertainty regarding the amount and availability of the federal ADAP budget for 2011-2012 and the lack of sufficient state funding. In the second quarter of 2011, only a portion of the full year federal budget was provided to the ADAPs, which resulted in conservative purchasing by individual state ADAPs during the quarter. Federal and state budget pressures, as well as the annual grant cycles for federal and state ADAP funds, may cause ADAP purchasing patterns to not reflect patient demand. As a result, we expect to continue to experience fluctuations in the purchasing patterns of our non-retail customers which may result in fluctuations in our product sales, revenues and earnings in the future.

In light of the global economic downturn and budget crises faced by many European countries, we have observed variations in purchasing patterns induced by cost containment measures in Europe. We believe these measures have caused some purchasers to reduce inventory of our products in the distribution channels, and in some cases, even at the patient level, which has decreased our revenues and caused fluctuations in our product sales and earnings. We may continue to see this trend in the future.

We face significant competition.

We face significant competition from large pharmaceutical and biotechnology companies, most of whom have substantially greater resources than we do. In addition, our competitors have more products and have operated in the fields in which we compete for longer than we have. Our HIV products compete primarily with products from the joint venture established by GlaxoSmithKline Inc. (GSK) and Pfizer Inc. (Pfizer) which markets fixed-dose combination products that compete with Atripla, Truvada and Complera/Eviplera. For example, lamivudine, marketed by this joint venture, is competitive with emtricitabine, the active pharmaceutical ingredient of Emtriva and a component of Atripla, Truvada and Complera/Eviplera.

We also face competition from generic HIV products. In May 2010, the compound patent covering Epivir (lamivudine) itself expired in the United States, and generic lamivudine is now available in the United States, Spain and Portugal, and recently received pricing approval in Italy. We expect that generic versions of lamivudine will be launched in other countries within the European Union. In May 2011, a generic version of Combivir (lamivudine and zidovudine) was approved and was recently launched in the United States. In addition, in late 2011, generic tenofovir also became available in Turkey.

For Viread and Hepsera for treatment of chronic hepatitis B, we compete primarily with products produced by GSK, Bristol-Myers Squibb Company (BMS) and Novartis Pharmaceuticals Corporation (Novartis) in the United States, the European Union and China. For AmBisome, we compete primarily with products produced by Merck & Co., Inc. (Merck) and Pfizer. In addition, we are aware of at least two lipid formulations that claim similarity to AmBisome becoming available outside of the United States, including the possible entry of one such formulation in Greece. These formulations may reduce market demand for AmBisome. Furthermore, the manufacture of lipid formulations of amphotericin B is very complex and if any of these formulations are found to be unsafe, sales of AmBisome may be negatively impacted by association. Letairis competes directly with a

product produced by Actelion Pharmaceuticals US, Inc. and indirectly with pulmonary arterial hypertension products from United Therapeutics Corporation and Pfizer. Ranexa competes predominantly with generic compounds from three distinct classes of drugs, beta-blockers, calcium channel blockers and long-acting nitrates for the treatment of chronic angina in the United States. Cayston competes with a product marketed by Novartis. Tamiflu competes with products sold by GSK and generic competitors.

In addition, a number of companies are pursuing the development of technologies which are competitive with our existing products or research programs. These competing companies include specialized pharmaceutical firms and large pharmaceutical companies acting either independently or together with other pharmaceutical companies. Furthermore, academic institutions, government agencies and other public and private organizations conducting research may seek patent protection and may establish collaborative arrangements for competitive products or programs.

If significant safety issues arise for our marketed products or our product candidates, our future sales may be reduced, which would adversely affect our results of operations.

The data supporting the marketing approvals for our products and forming the basis for the safety warnings in our product labels were obtained in controlled clinical trials of limited duration and, in some cases, from post-approval use. As our products are used over longer periods of time by many patients with underlying health problems, taking numerous other medicines, we expect to continue to find new issues such as safety, resistance or drug interaction issues, which may require us to provide additional warnings or contraindications on our labels or narrow our approved indications, each of which could reduce the market acceptance of these products.

Our product Letairis, which was approved by the FDA in June 2007, is a member of a class of compounds called endothelin receptor antagonists (ERAs) which pose specific risks, including serious risks of birth defects. Because of these risks, Letairis is available only through the Letairis Education and Access Program (LEAP), a restricted distribution program intended to help physicians and patients learn about the risks associated with the product and assure appropriate use of the product. As the product is used by additional patients, we may discover new risks associated with Letairis which may result in changes to the distribution program and additional restrictions on the use of Letairis which may decrease demand for the product.

If serious safety, resistance or drug interaction issues arise with our marketed products, sales of these products could be limited or halted by us or by regulatory authorities and our results of operations would be adversely affected.

Our operations depend on compliance with complex FDA and comparable international regulations. Failure to obtain broad approvals on a timely basis or to maintain compliance could delay or halt commercialization of our products.

The products we develop must be approved for marketing and sale by regulatory authorities and, once approved, are subject to extensive regulation by the FDA, the European Medicines Agency and comparable regulatory agencies in other countries. We are continuing clinical trials for Atripla, Truvada, Viread, Hepsera, Complera/Eviplera, Emtriva, AmBisome, Letairis, Ranexa and Cayston for currently approved and additional uses. We anticipate that we will file for marketing approval in additional countries and for additional indications and products over the next several years. These products may fail to receive such marketing approvals on a timely basis, or at all.

Further, our marketed products and how we manufacture and sell these products are subject to extensive regulation and review. Discovery of previously unknown problems with our marketed products or problems with our manufacturing or promotional activities may result in restrictions on our products, including withdrawal of the products from the market. If we fail to comply with applicable regulatory requirements, including those related to promotion and manufacturing, we could be subject to penalties including fines, suspensions of regulatory approvals, product recalls, seizure of products and criminal prosecution.

On September 27, 2007, President Bush signed into law the Food and Drug Administration Amendments Act of 2007, which significantly expanded the FDA’s authority, including, among other things, to:

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require sponsors of marketed products to conduct post-approval clinical studies to assess a known serious risk, signals of serious risk or to identify an unexpected serious risk;

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mandate labeling changes to products, at any point in a product’s lifecycle, based on new safety information; and

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require sponsors to implement a Risk Evaluation and Mitigation Strategy for a product which could include a medication guide, patient package insert, a communication plan to healthcare providers or other elements as the FDA deems are necessary to assure safe use of the drug, which could include imposing certain restrictions on the distribution or use of a product.

Failure to comply with these or other requirements, if imposed on a sponsor by the FDA, could result in significant civil monetary penalties and our operating results may be adversely affected.

The results and anticipated timelines of our clinical trials are uncertain and may not support continued development of a product pipeline, which would adversely affect our prospects for future revenue growth.

We are required to demonstrate the safety and efficacy of products that we develop for each intended use through extensive preclinical studies and clinical trials. The results from preclinical and early clinical studies do not always accurately predict results in later, large-scale clinical trials. Even successfully completed large-scale clinical trials may not result in marketable products. If any of our product candidates fails to achieve its primary endpoint in clinical trials, if safety issues arise or if the results from our clinical trials are otherwise inadequate to support regulatory approval of our product candidates, commercialization of that product candidate could be delayed or halted. For example, in January 2011, we announced our decision to terminate our Phase 3 clinical trial of ambrisentan in patients with IPF and, in April 2011, we announced our decision to terminate our Phase 3 clinical trial of aztreonam for inhalation solution for the treatment of CF in patients with Burkholderia spp. In addition, we may also face challenges in clinical trial protocol design. If the clinical trials for any of the product candidates in our pipeline are delayed or terminated, our prospects for future revenue growth would be adversely impacted. For example, we face numerous risks and uncertainties with our product candidates, including GS-7977 for the treatment of hepatitis C, aztreonam for inhalation solution for the treatment of bronchiectasis and ranolazine for the treatment of incomplete revascularization post-percutaneous coronary intervention and type II diabetes, each currently in Phase 3 clinical trials, that could prevent completion of development of these product candidates. These risks include our ability to enroll patients in clinical trials, the possibility of unfavorable results of our clinical trials, the need to modify or delay our clinical trials or to perform additional trials and the risk of failing to obtain FDA and other regulatory body approvals. As a result, our product candidates may never be successfully commercialized. Further, we may make a strategic decision to discontinue development of our product candidates if, for example, we believe commercialization will be difficult relative to other opportunities in our pipeline. If these programs and others in our pipeline cannot be completed on a timely basis or at all, then our prospects for future revenue growth may be adversely impacted. In addition, clinical trials involving our commercial products could raise new safety issues for our existing products, which could in turn decrease our revenues and harm our business.

Due to our reliance on third-party contract research organizations to conduct our clinical trials, we are unable to directly control the timing, conduct, expense and quality of our clinical trials.

We extensively outsource our clinical trial activities and usually perform only a small portion of the start-up activities in-house. We rely on independent third-party contract research organizations (CROs) to perform most of our clinical studies, including document preparation, site identification, screening and preparation, pre-study visits, training, program management and bioanalytical analysis. Many important aspects of the services performed for us by the CROs are out of our direct control. If there is any dispute or disruption in our

relationship with our CROs, our clinical trials may be delayed. Moreover, in our regulatory submissions, we rely on the quality and validity of the clinical work performed by third-party CROs. If any of our CROs’ processes, methodologies or results were determined to be invalid or inadequate, our own clinical data and results and related regulatory approvals could be adversely impacted.

We depend on relationships with other companies for sales and marketing performance, development and commercialization of product candidates and revenues. Failure to maintain these relationships, poor performance by these companies or disputes with these companies could negatively impact our business.

We rely on a number of significant collaborative relationships with major pharmaceutical companies for our sales and marketing performance in certain territories. These include collaborations with BMS for Atripla in the United States, Europe and Canada; F. Hoffmann-La Roche Ltd. (together with Hoffmann-La Roche Inc., Roche) for Tamiflu worldwide; and GSK for ambrisentan in territories outside of the United States. In some countries, we rely on international distributors for sales of Truvada, Viread, Hepsera, Emtriva and AmBisome. Some of these relationships also involve the clinical development of these products by our partners. Reliance on collaborative relationships poses a number of risks, including the risk that:

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we are unable to control the resources our corporate partners devote to our programs or products;

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disputes may arise with respect to the ownership of rights to technology developed with our corporate partners;

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disagreements with our corporate partners could cause delays in, or termination of, the research, development or commercialization of product candidates or result in litigation or arbitration;

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contracts with our corporate partners may fail to provide significant protection or may fail to be effectively enforced if one of these partners fails to perform;

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our corporate partners have considerable discretion in electing whether to pursue the development of any additional products and may pursue alternative technologies or products either on their own or in collaboration with our competitors;

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our corporate partners with marketing rights may choose to pursue competing technologies or to devote fewer resources to the marketing of our products than they do to products of their own development; and

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our distributors and our corporate partners may be unable to pay us, particularly in light of current economic conditions.

Given these risks, there is a great deal of uncertainty regarding the success of our current and future collaborative efforts. If these efforts fail, our product development or commercialization of new products could be delayed or revenues from products could decline.

We also rely on collaborative relationships with major pharmaceutical companies for development and commercialization of certain product candidates. Gilead (as successor to Pharmasset, Inc.) is a party to a collaboration agreement with Roche to develop PSI-6130 and its prodrugs for the treatment of chronic HCV infection. The collaborative research efforts under this agreement ended on December 31, 2006. Roche later asked Pharmasset to consider whether Roche may have contributed to the inventorship of GS-7977 and whether Pharmasset has complied with the confidentiality provisions of the collaboration agreement. Pharmasset advised us that it carefully considered the issues raised by Roche and that it believed any such issues are without merit. We have also considered these issues and reached the same conclusion. However, if Roche were to successfully assert that it contributed to the inventorship of GS-7977 and either independently develop GS-7977 or file an abbreviated new drug application (ANDA) to market GS-7977, Roche could at some point in the future market that product and begin competing against us prior to the expiration of our patents for GS-7977. Such marketing activity by Roche could materially reduce the revenues we expect to receive from the sale of GS-7977, which could adversely affect our results of operations.

Under our April 2002 licensing agreement with GSK, we gave GSK the right to control clinical and regulatory development and commercialization of Hepsera in territories in Asia, Africa and Latin America. These include major markets for Hepsera, such as China, Japan, Taiwan and South Korea. In November 2009, we entered into an agreement with GSK that provided GSK with exclusive commercialization rights and registration responsibilities for Viread for the treatment of chronic hepatitis B in China. In October 2010, we granted similar rights to GSK in Japan and Saudi Arabia. The success of Hepsera and Viread for the treatment of chronic hepatitis B in these territories depends almost entirely on the efforts of GSK. In this regard, GSK promotes Epivir-HBV/Zeffix, a product that competes with Hepsera and Viread for the treatment of chronic hepatitis B. Consequently, GSK’s marketing strategy for Hepsera and Viread for the treatment of chronic hepatitis B may be influenced by its promotion of Epivir-HBV/Zeffix. We receive royalties from GSK equal to a percentage of GSK’s net sales of Hepsera and Viread for the treatment of chronic hepatitis B as well as net sales of GSK’s Epivir-HBV/Zeffix. If GSK fails to devote sufficient resources to, or does not succeed in developing or commercializing Hepsera or Viread for the treatment of chronic hepatitis B in its territories, our potential revenues in these territories may be substantially reduced.

In addition, Cayston and Letairis are distributed through third-party specialty pharmacies, which are pharmacies specializing in the dispensing of medications for complex or chronic conditions that may require a high level of patient education and ongoing counseling. The use of specialty pharmacies requires significant coordination with our sales and marketing, medical affairs, regulatory affairs, legal and finance organizations and involves risks, including but not limited to risks that these specialty pharmacies will:

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not provide us with accurate or timely information regarding their inventories, patient data or safety complaints;

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not effectively sell or support Cayston or Letairis;

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not devote the resources necessary to sell Cayston or Letairis in the volumes and within the time frames that we expect;

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not be able to satisfy their financial obligations to us or others; or

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cease operations.

We also rely on a third party to administer LEAP, the restricted distribution program designed to support Letairis. This third party provides information and education to prescribers and patients on the risks of Letairis, confirms insurance coverage and investigates alternative sources of reimbursement or assistance, ensures fulfillment of the risk management requirements mandated for Letairis by the FDA and coordinates and controls dispensing to patients through the third-party specialty pharmacies. Failure of this third party or the specialty pharmacies that distribute Letairis to perform as expected may result in regulatory action from the FDA or decreased Letairis sales, either of which would harm our business.

Further, Cayston may only be taken by patients using a specific inhalation device that delivers the drug to the lungs of patients. Our ongoing distribution of Cayston is entirely reliant upon the manufacturer of that device. For example, the manufacturer could encounter other issues with regulatory agencies related to the device or be unable to supply sufficient quantities of this device. In addition, the manufacturer may not be able to provide adequate warranty support for the device after it has been distributed to patients. With respect to distribution of the drug and device to patients, we are reliant on the capabilities of specialty pharmacies. For example, the distribution channel for drug and device is complicated and requires coordination. The reimbursement approval processes associated with both drug and device are similarly complex. If the device manufacturer is unable to obtain reimbursement approval or receives approval at a lower-than-expected price, sales of Cayston may be adversely affected. Any of the previously described issues may limit the sales of Cayston, which would adversely affect our financial results.

Expenses associated with clinical trials may cause our earnings to fluctuate, which could adversely affect our stock price.

The clinical trials required for regulatory approval of our products, as well as clinical trials we are required to conduct after approval, are very expensive. It is difficult to accurately predict or control the amount or timing of these expenses from quarter to quarter, and the FDA and/or other regulatory agencies may require more clinical testing than we originally anticipated. Uneven and unexpected spending on these programs may cause our operating results to fluctuate from quarter to quarter, and our stock price may decline.

Our success will depend to a significant degree on our ability to protect our patents and other intellectual property rights both domestically and internationally. We may not be able to obtain effective patents to protect our technologies from use by competitors and patents of other companies could require us to stop using or pay for the use of required technology.

Patents and other proprietary rights are very important to our business. Our success will depend to a significant degree on our ability to:

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obtain patents and licenses to patent rights;

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preserve trade secrets; and

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operate without infringing on the proprietary rights of others.

If we have a properly drafted and enforceable patent, it can be more difficult for our competitors to use our technology to create competitive products and more difficult for our competitors to obtain a patent that prevents us from using technology we create. As part of our business strategy, we actively seek patent protection both in the United States and internationally and file additional patent applications, when appropriate, to cover improvements in our compounds, products and technology.

We have a number of U.S. and foreign patents, patent applications and rights to patents related to our compounds, products and technology, but we cannot be certain that issued patents will be enforceable or provide adequate protection or that pending patent applications will result in issued patents. Patent applications are confidential for a period of time before a patent is issued. As a result, we may not know if our competitors filed patent applications for technology covered by our pending applications or if we were the first to invent the technology that is the subject of our patent applications. Competitors may have filed patent applications or received patents and may obtain additional patents and proprietary rights that block or compete with our products. In addition, if competitors file patent applications covering our technology, we may have to participate in interference proceedings or litigation to determine the right to a patent. Litigation and interference proceedings are unpredictable and expensive, such that, even if we are ultimately successful, our results of operations may be adversely affected by such events.

From time to time, certain individuals or entities may challenge our patents. For example, in 2007, the Public Patent Foundation filed requests for re-examination with the United States Patent and Trademark Office (PTO) challenging four of our patents related to tenofovir disoproxil fumarate, which is an active ingredient in Atripla, Truvada and Viread. The PTO granted these requests and issued non-final rejections for the four patents, which is a step common in a proceeding to initiate the re-examination process. In 2008, the PTO confirmed the patentability of all four patents.

then filed an appeal within the patent authority responding to the questions raised in the rejection. In July 2009, the Brazilian patent authority again rejected the application. This was the highest level of appeal available to us within the Brazilian patent authority. We have filed a civil action in Brazilian federal court to further appeal the action of the Brazilian patent authority. Because we do not currently have a patent in Brazil, in 2011 the Brazilian government purchased all of its supply of tenofovir disoproxil fumarate from generic manufacturers. As a result, we did not sell any of our HIV products in Brazil in 2011.

Patents do not cover the ranolazine compound, the active ingredient of Ranexa. Instead, when it was discovered that only a sustained release formulation of ranolazine would achieve therapeutic plasma levels, patents were obtained on those formulations and the characteristic plasma levels they achieve. Patents do not cover the active ingredients in AmBisome. In addition, we do not have patent filings in China or certain other Asian countries covering all forms of adefovir dipivoxil, the active ingredient in Hepsera. Asia is a major market for therapies for hepatitis B, the indication for which Hepsera has been developed.

We may obtain patents for certain products many years before marketing approval is obtained for those products. Because patents have a limited life, which may begin to run prior to the commercial sale of the related product, the commercial value of the patent may be limited. However, we may be able to apply for patent term extensions in some countries.

As part of the approval process of some of our products, the FDA granted an exclusivity period during which other manufacturers’ applications for approval of generic versions of our product will not be granted. Generic manufacturers often wait to challenge the patents protecting products that have been granted exclusivity until one year prior to the end of the exclusivity period. From time to time, we have received notices from manufacturers indicating that they intend to import chemical intermediates possibly for use in making our products. Generic manufacturers have sought and may continue to seek FDA approval for a similar or identical drug through an abbreviated new drug application (ANDA), the application form typically used by manufacturers seeking approval of a generic drug.

related to emtricitabine and two patents related to efavirenz. In March 2010, we filed a lawsuit against Teva for infringement of the four Viread patents and two additional emtricitabine patents. In March 2010, BMS and Merck filed a lawsuit against Teva for infringement of the patents related to efavirenz.

We cannot predict the ultimate outcome of these actions, and we may spend significant resources enforcing and defending these patents. If we are unsuccessful in these lawsuits, some or all of our original claims in the patents may be narrowed or invalidated and the patent protection for Atripla, Truvada, Viread, Hepsera, Ranexa and Tamiflu in the United States or Atripla and Truvada in Canada could be substantially shortened. Further, if all of the patents covering those products are invalidated, the FDA could approve the requests to manufacture a generic version of such products prior to the expiration date of those patents.

Our success depends in large part on our ability to operate without infringing upon the patents or other proprietary rights of third parties.

If we infringe the patents of others, we may be prevented from commercializing products or may be required to obtain licenses from these third parties. We may not be able to obtain alternative technologies or any required license on reasonable terms or at all. If we fail to obtain these licenses or alternative technologies, we may be unable to develop or commercialize some or all of our products. For example, we are aware of a body of patents that may relate to our operation of LEAP, our restricted distribution program designed to support Letairis.

We own patents that claim GS-7977 as a chemical entity and its metabolites. However, the existence of issued patents does not guarantee our right to practice the patented technology or commercialize the patented product. Third parties may have or obtain rights to patents which they may claim could be used to prevent or attempt to prevent us from commercializing the patented product candidates obtained from the Pharmasset acquisition. For example, we are aware of patents and patent applications owned by other parties that might be alleged to cover the use of GS-7977. If these other parties are successful in obtaining valid and enforceable patents, and establishing our infringement of those patents, we could be prevented from selling GS-7977 unless we were able to obtain a license under such patents. If any license is needed it may not be available on commercially reasonable terms or at all.

Furthermore, we use significant proprietary technology and rely on unpatented trade secrets and proprietary know-how to protect certain aspects of our production and other technologies. Our trade secrets may become known or independently discovered by our competitors.

Manufacturing problems, including at our third-party manufacturers and corporate partners, could cause inventory shortages and delay product shipments and regulatory approvals, which may adversely affect our results of operations.

In order to generate revenue from our products, we must be able to produce sufficient quantities of our products to satisfy demand. Many of our products are the result of complex manufacturing processes. The manufacturing process for pharmaceutical products is also highly regulated and regulators may shut down manufacturing facilities that they believe do not comply with regulations.

Our products are either manufactured at our own facilities or by third-party manufacturers or corporate partners. We depend on third parties to perform manufacturing activities effectively and on a timely basis for the majority of our solid dose products. In addition, Roche, either by itself or through third parties, is responsible for manufacturing Tamiflu. We, our third-party manufacturers and our corporate partners are subject to current Good Manufacturing Practices (GMP), which are extensive regulations governing manufacturing processes, stability testing, record keeping and quality standards as defined by the FDA and the European Medicines Agency. Similar regulations are in effect in other countries.

Our third-party manufacturers and corporate partners are independent entities who are subject to their own unique operational and financial risks which are out of our control. If we or any of these third-party manufacturers or corporate partners fail to perform as required, this could impair our ability to deliver our products on a timely basis or receive royalties or cause delays in our clinical trials and applications for regulatory approval. To the extent these risks materialize and affect their performance obligations to us, our financial results may be adversely affected.

In addition, we, our third-party manufacturers and our corporate partners may only be able to produce some of our products at one or a limited number of facilities and, therefore, have limited manufacturing capacity for certain products. For example, we currently manufacture Cayston exclusively at our San Dimas, California manufacturing facility. Due to unexpected delays both in qualifying two new external sites and with expanding Cayston manufacturing in San Dimas, we cannot supply enough Cayston to fulfill our projected demand. In February 2012, we suspended access for patients with new prescriptions for Cayston subject to certain exceptions where specific medical need exists. Patients may use other alternative treatment options until we are able to resolve the supply shortage. As a result of our inability to manufacture sufficient Cayston to meet demand, the amount of revenues we expect to receive from the sale of Cayston will be reduced.

Our manufacturing operations are subject to routine inspections by regulatory agencies. For example, in January and February 2010, the FDA conducted a routine inspection of our San Dimas manufacturing facility, where we exclusively manufacture Cayston and AmBisome and fill and finish Macugen. At the conclusion of that inspection, the FDA issued Form 483 Inspectional Observations stating concerns over: the maintenance of

aseptic processing conditions in the manufacturing suite for our AmBisome product; environmental maintenance issues in the San Dimas warehousing facility; batch sampling; and the timeliness of completion of annual product quality reports. On September 24, 2010, our San Dimas manufacturing facility received a Warning Letter from the FDA further detailing the FDA’s concerns over the AmBisome manufacturing environment, including control systems and monitoring, procedures to prevent microbiological contamination and preventative cleaning and equipment maintenance. Referencing certain Viread lots, the letter also stated concerns connected with quality procedures, controls and investigation procedures, and a generalized concern over the effectiveness of the San Dimas quality unit in carrying out its responsibilities. In November and December 2010, the FDA re-inspected the San Dimas facility. The re-inspection closed with no additional Form 483 observations. In August 2011, the FDA notified us that we resolved all issues raised by the FDA in its Warning Letter.

Our ability to successfully manufacture and commercialize Cayston will depend upon our ability to manufacture in a multi-product facility.

Aztreonam, the active pharmaceutical ingredient in Cayston, is a mono-bactam Gram-negative antibiotic. We manufacture Cayston by ourselves in San Dimas, California, or through third parties, in multi-product manufacturing facilities. Historically, the FDA has permitted the manufacture of mono-bactams in multi-product manufacturing facilities; however, there can be no assurance that the FDA will continue to allow this practice. We do not currently have a single-product facility that can be dedicated to the manufacture of Cayston nor have we engaged a contract manufacturer with a single-product facility for Cayston. If the FDA prohibits the manufacture of mono-bactam antibiotics, like aztreonam, in multi-product manufacturing facilities in the future, we may not be able to procure a single-product manufacturing facility in a timely manner, which would adversely affect our commercial supplies of Cayston and our anticipated financial results attributable to such product.

We may not be able to obtain materials or supplies necessary to conduct clinical trials or to manufacture and sell our products, which would limit our ability to generate revenues.

We need access to certain supplies and products to conduct our clinical trials and to manufacture our products. In light of the global economic downturn, we have had increased difficulty in purchasing certain of the raw materials used in our manufacturing process. If we are unable to purchase sufficient quantities of these materials or find suitable alternate materials in a timely manner, our development efforts for our product candidates may be delayed or our ability to manufacture our products would be limited, which would limit our ability to generate revenues.

Suppliers of key components and materials must be named in an NDA filed with the FDA, EMA or other regulatory authority for any product candidate for which we are seeking marketing approval, and significant delays can occur if the qualification of a new supplier is required. Even after a manufacturer is qualified by the regulatory authority, the manufacturer must continue to expend time, money and effort in the area of production and quality control to ensure full compliance with GMP. Manufacturers are subject to regular, periodic inspections by the regulatory authorities following initial approval. If, as a result of these inspections, a regulatory authority determines that the equipment, facilities, laboratories or processes do not comply with applicable regulations and conditions of product approval, the regulatory authority may suspend the manufacturing operations. If the manufacturing operations of any of the single suppliers for our products are suspended, we may be unable to generate sufficient quantities of commercial or clinical supplies of product to meet market demand, which would in turn decrease our revenues and harm our business. In addition, if delivery of material from our suppliers were interrupted for any reason, we may be unable to ship certain of our products for commercial supply or to supply our products in development for clinical trials. In addition, some of our products and the materials that we utilize in our operations are made at only one facility. For example, we manufacture AmBisome and fill and finish Macugen exclusively at our facilities in San Dimas, California. In the event of a disaster, including an earthquake, equipment failure or other difficulty, we may be unable to replace this manufacturing capacity in a timely manner and may be unable to manufacture AmBisome and Macugen to meet market needs.

Cayston is dependent on two different third-party single-source suppliers. First, aztreonam, the active pharmaceutical ingredient in aztreonam for inhalation solution, is manufactured by a single supplier at a single site. Second, it is administered to the lungs of patients through a device that is made by a single supplier at a single site. Disruptions or delays with any of these single suppliers could adversely affect our ability to supply Cayston, and we cannot be sure that alternative suppliers can be identified in a timely manner, or at all. See the Risk Factor entitled “Our ability to successfully manufacture and commercialize Cayston will depend upon our ability to manufacture in a multi-product facility.”

In addition, we depend on a single supplier for high-quality cholesterol, which is used in the manufacture of AmBisome. We also rely on a single source for the active pharmaceutical ingredient of Ranexa, Hepsera, Letairis and Vistide and for the tableting of Letairis. Astellas US LLC, which markets Lexiscan in the United States, is responsible for the commercial manufacture and supply of product in the United States and is dependent on a single supplier for the active pharmaceutical ingredient of Lexiscan. Problems with any of the single suppliers we depend on may negatively impact our development and commercialization efforts.

A significant portion of the raw materials and intermediates used to manufacture our HIV products (Atripla, Truvada, Viread, Complera/Eviplera, Emtriva) are supplied by Chinese-based companies. As a result, an international trade dispute between China and the United States or any other actions by the Chinese government that would limit or prevent Chinese companies from supplying these materials would adversely affect our ability to manufacture and supply our HIV products to meet market needs and have a material and adverse effect on our operating results.

We face credit risks from our Southern European customers that may adversely affect our results of operations.

Our European product sales to government-owned or supported customers in Southern Europe, specifically Greece, Italy, Portugal and Spain have historically been and continue to be subject to significant payment delays due to government funding and reimbursement practices. This has resulted and may continue to result in days sales outstanding being significantly higher in these countries due to the average length of time that accounts receivable remain outstanding. As of December 31, 2011, our accounts receivable in these countries totaled approximately $1.10 billion of which, $612.4 million were past due greater than 120 days and $250.7 million were past due greater than 365 days as follows (in thousands):


	December 31, 2011
	Greater than 120 days past due		Greater than 365 days past due
Italy	$	102,228	$	28,328
Spain		404,123		187,780
Portugal		94,029		33,092
Greece		12,067		1,535

Total	$	612,447	$	250,735

As a result of the fiscal and debt crises in these countries, the number of days our invoices are past due has continued to increase in line with that being experienced by other pharmaceutical companies that are also selling directly to hospitals. Historically, receivable balances with certain publicly-owned hospitals accumulate over a period of time and are then subsequently settled as large lump sum payments. If significant changes were to occur in the reimbursement practices of these European governments or if government funding becomes unavailable, we may not be able to collect on amounts due to us from these customers and our results of operations would be adversely affected. For example, in 2011, the Greek government settled substantially all of its outstanding receivables subject to the bond settlement with zero-coupon bonds that trade at a discount to face

value. Through December 31, 2011, we received a total of $63.5 million in bonds. Our allowance for doubtful accounts was adequate to cover the exposure related to the discount on these bonds. In Spain, Italy and Portugal we are actively pursuing collection of the overdue receivables and taking action as necessary to enforce our legal right to payment.

Our revenues and gross margin could be reduced by imports from countries where our products are available at lower prices.

Prices for our products are based on local market economics and competition and sometimes differ from country to country. Our sales in countries with relatively higher prices may be reduced if products can be imported into those or other countries from lower price markets. There have been cases in which other pharmaceutical products were sold at steeply discounted prices in the developing world and then re-exported to European countries where they could be re-sold at much higher prices. If this happens with our products, particularly Truvada and Viread, which we have agreed to make available at substantially reduced prices to 134 countries participating in our Gilead Access Program, or Atripla, which Merck distributes at substantially reduced prices to HIV infected patients in developing countries under our 2006 agreement, our revenues would be adversely affected. In addition, we have established partnerships with thirteen Indian generic manufacturers to distribute high-quality, low-cost generic versions of tenofovir disoproxil fumarate to 112 developing world countries, including India. If generic versions of our medications under these licenses are then re-exported to the United States, Europe or other markets outside of these 112 countries, our revenues would be adversely affected.

In addition, purchases of our products in countries where our selling prices are relatively low for resale in countries in which our selling prices are relatively high may adversely impact our revenues and gross margin and may cause our sales to fluctuate from quarter to quarter. For example, in the European Union, we are required to permit products purchased in one country to be sold in another country. Purchases of our products in countries where our selling prices are relatively low for resale in countries in which our selling prices are relatively high affect the inventory level held by our wholesalers and can cause the relative sales levels in the various countries to fluctuate from quarter to quarter and not reflect the actual consumer demand in any given quarter. These quarterly fluctuations may impact our earnings, which could adversely affect our stock price and harm our business.

Expensive litigation and government investigations have reduced and may continue to reduce our earnings.

In November 2008, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Truvada. In the notice, Teva alleges that two of the patents associated with emtricitabine are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Truvada. In December 2008, we filed a lawsuit against Teva for infringement of the two emtricitabine patents. In March 2009, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Atripla. In the notice, Teva challenged the same two emtricitabine patents. In May 2009, we filed another lawsuit against Teva for infringement of the two emtricitabine patents, and this lawsuit was consolidated with the lawsuit filed in December 2008. In January 2010, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Viread. In the notice, Teva challenged four of the tenofovir disoproxil fumarate patents protecting Viread. In January 2010, we also received notices from Teva amending its ANDAs related to Atripla and Truvada. In the notice related to Truvada, Teva challenged four patents related to tenofovir disoproxil fumarate and two additional patents related to emtricitabine. In the notice related to Atripla, Teva challenged four patents related to tenofovir disoproxil fumarate, two additional patents related to emtricitabine and two patents related to efavirenz. In March 2010, we filed a lawsuit against Teva for infringement of the four Viread patents and two additional emtricitabine patents. In March 2010, BMS and Merck filed a lawsuit against Teva for infringement of the patents related to efavirenz.

In June 2010, we received notice that Lupin submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Ranexa. In the notice, Lupin alleges that ten of the patents associated with Ranexa are invalid, unenforceable and/or will not be infringed by Lupin’s manufacture, use or sale of a generic version of Ranexa. In July 2010, we filed a lawsuit against Lupin for infringement of our patents for Ranexa.

In August 2010, we received notice that Sigmapharm submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Hepsera. In the notice, Sigmapharm alleges that both of the patents associated with Hepsera are invalid, unenforceable and/or will not be infringed by Sigmapharm’s manufacture, use or sale of a generic version of Hepsera. In September 2010, we filed a lawsuit against Sigmapharm for infringement of our patents for Hepsera. One of the patents challenged by Sigmapharm is also being challenged by Ranbaxy pursuant to a notice received in October 2010. The patent challenged by Ranbaxy expires in July 2018. We are considering our options for enforcing our patent.

In February 2011, we received notice that Natco submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Tamiflu. In the notice, Natco alleges that one of the patents associated with Tamiflu is invalid, unenforceable and/or will not be infringed by Natco’s manufacture, use or sale of a generic version of Tamiflu. In March 2011, we and Roche filed a lawsuit against Natco for infringement of the patent associated with Tamiflu.

We cannot predict the ultimate outcome of these actions, and we may spend significant resources enforcing and defending these patents. If we are unsuccessful in these lawsuits, some or all of our original claims in the patents may be narrowed or invalidated and the patent protection for Atripla, Truvada, Viread, Hepsera, Ranexa and Tamiflu in the United States and Atripla and Viread in Canada could be substantially shortened. Further, if all of the patents covering those products are invalidated, the FDA could approve the requests to manufacture a generic version of such products prior to the expiration date of those patents.

In addition, in June 2011, we received a subpoena from the United States Attorney’s Office for the Northern District of California requesting documents related to the manufacture, and related quality and distribution practices, of Atripla, Emtriva, Hepsera, Letairis, Truvada, Viread and Complera.

The outcome of the lawsuits above, or any other lawsuits that may be brought against us, the investigation or any other investigations that may be initiated, are inherently uncertain, and adverse developments or outcomes can result in significant expenses, monetary damages, penalties or injunctive relief against us that could significantly reduce our earnings and cash flows and harm our business.

In some countries, we may be required to grant compulsory licenses for our products or face generic competition for our products.

In a number of developing countries, government officials and other interested groups have suggested that pharmaceutical companies should make drugs for HIV infection available at low cost. Alternatively, governments in those developing countries could require that we grant compulsory licenses to allow competitors to manufacture and sell their own versions of our products, thereby reducing our product sales. For example, in the past, certain offices of the government of Brazil have expressed concern over the affordability of our HIV products and declared that they were considering issuing compulsory licenses to permit the manufacture of otherwise patented products for HIV infection, including Viread. In July 2009, the Brazilian patent authority rejected our patent application for tenofovir disoproxil fumarate, the active pharmaceutical ingredient in Viread. This was the highest level of appeal available to us within the Brazilian patent authority. Because we do not currently have a patent in Brazil, in 2011 the Brazilian government purchased all of its supply of tenofovir disoproxil fumarate from generic manufacturers. As a result, we did not sell any of our HIV products in Brazil in 2011.

In addition, concerns over the cost and availability of Tamiflu related to a potential avian flu pandemic and H1N1 influenza generated international discussions over compulsory licensing of our Tamiflu patents. For example, the Canadian government considered allowing Canadian manufacturers to manufacture and export the active ingredient in Tamiflu to eligible developing and least developed countries under Canada’s Access to Medicines Regime. Furthermore, Roche issued voluntary licenses to permit third-party manufacturing of Tamiflu. For example, Roche granted a sublicense to Shanghai Pharmaceutical (Group) Co., Ltd. for China and a sublicense to India’s Hetero Drugs Limited for India and certain developing countries. Should one or more compulsory licenses be issued permitting generic manufacturing to override our Tamiflu patents, or should Roche issue additional voluntary licenses to permit third-party manufacturing of Tamiflu, those developments could reduce royalties we receive from Roche’s sales of Tamiflu. Certain countries do not permit enforcement of our patents, and third-party manufacturers are able to sell generic versions of our products in those countries. Compulsory licenses or sales of generic versions of our products could significantly reduce our sales and adversely affect our results of operations, particularly if generic versions of our products are imported into territories where we have existing commercial sales.

Changes in royalty revenue disproportionately affect our pre-tax income, earnings per share and gross margins.

A portion of our revenues is derived from royalty revenues recognized from collaboration agreements with third parties. Royalty revenues impact our pre-tax income, earnings per share and gross margins disproportionately more than their contributions to our revenues. Any increase or decrease to our royalty revenue could be material and could significantly impact our operating results. For example, we recognized $75.5 million in royalty revenue for the year ended December 31, 2011 related to royalties received from sales of Tamiflu by F. Hoffmann-La Roche Ltd (together with Hoffmann-La Roche Inc., Roche). Although such royalty revenue represented approximately 1% of our total revenues in 2011, it represented approximately 2% of our pre-tax income during the period. Roche’s Tamiflu sales have unpredictable variability due to their strong relationship with global pandemic planning efforts. Tamiflu royalties increased sharply in 2009 and the first quarter of 2010 primarily as a result of pandemic planning initiatives worldwide. Tamiflu royalties since the second quarter of 2010 have decreased due to declining pandemic planning initiatives worldwide.

We may face significant liability resulting from our products that may not be covered by insurance and successful claims could materially reduce our earnings.

The testing, manufacturing, marketing and use of our commercial products, as well as product candidates in development, involve substantial risk of product liability claims. These claims may be made directly by consumers, healthcare providers, pharmaceutical companies or others. In recent years, coverage and availability

of cost-effective product liability insurance has decreased, so we may be unable to maintain sufficient coverage for product liabilities that may arise. In addition, the cost to defend lawsuits or pay damages for product liability claims may exceed our coverage. If we are unable to maintain adequate coverage or if claims exceed our coverage, our financial condition and our ability to clinically test our product candidates and market our products will be adversely impacted. In addition, negative publicity associated with any claims, regardless of their merit, may decrease the future demand for our products and impair our financial condition.

Business disruptions from natural or man-made disasters may harm our future revenues.

Our worldwide operations could be subject to business interruptions stemming from natural or man-made disasters for which we may be self-insured. Our corporate headquarters and Palo Alto locations, which together house a majority of our research and development activities, and our San Dimas and Oceanside manufacturing facilities are located in California, a seismically active region. As we do not carry earthquake insurance and significant recovery time could be required to resume operations, our financial condition and operating results could be materially adversely affected in the event of a major earthquake.

Changes in our effective income tax rate could reduce our earnings.

Various factors may have favorable or unfavorable effects on our income tax rate. These factors include, but are not limited to, interpretations of existing tax laws, changes in tax laws and rates, our portion of the non-deductible pharmaceutical excise tax, the accounting for stock options and other share-based payments, mergers and acquisitions, future levels of R&D spending, changes in accounting standards, changes in the mix of earnings in the various tax jurisdictions in which we operate, changes in overall levels of pre-tax earnings and resolution of federal, state and foreign income tax audits. The impact on our income tax provision resulting from the above mentioned factors may be significant and could have a negative impact on our net income.

Our income tax returns are audited by federal, state and foreign tax authorities. We are currently under examination by the Internal Revenue Service for the 2008 and 2009 tax years and by various state and foreign jurisdictions. There are differing interpretations of tax laws and regulations, and as a result, significant disputes may arise with these tax authorities involving issues of the timing and amount of deductions and allocations of income among various tax jurisdictions. Resolution of one or more of these exposures in any reporting period could have a material impact on the results of operations for that period.

If we fail to attract and retain highly qualified personnel, we may be unable to successfully develop new product candidates, conduct our clinical trials and commercialize our product candidates.

Our future success will depend in large part on our continued ability to attract and retain highly qualified scientific, technical and management personnel, as well as personnel with expertise in clinical testing, governmental regulation and commercialization. We face competition for personnel from other companies, universities, public and private research institutions, government entities and other organizations. Competition for qualified personnel in the biopharmaceutical field is intense, and there is a limited pool of qualified potential employees to recruit. We may not be able to attract and retain quality personnel on acceptable terms. If we are unsuccessful in our recruitment and retention efforts, our business may be harmed.

ITEM 1B.

UNRESOLVED STAFF COMMENTS

Not applicable.

ITEM 2.

PROPERTIES

We lease facilities in Foster City, Palo Alto, Fremont and San Dimas, California, to house some of our manufacturing, warehousing and R&D activities. In addition, we also lease facilities in Branford, Connecticut; Princeton, New Jersey; Durham, North Carolina; and Seattle, Washington to house some of our administrative and R&D activities.

Our international headquarters, which include some of our commercial, medical and administrative facilities, are located and leased in the London area in the United Kingdom.

We own a manufacturing facility in Cork, Ireland, that we primarily use for solid dose tablet manufacturing of our antiviral products, as well as product packaging activities. We also lease a facility in Cork used for shared services. We lease and own facilities in the Dublin area of Ireland to house distribution activities.

We own a manufacturing facility in Edmonton, Alberta, Canada, that we primarily use to conduct process research and scale-up of our clinical development candidates, the manufacturing of our active pharmaceutical ingredients for both investigational and commercial products and our chemical development activities to improve existing commercial manufacturing processes.

We also own a manufacturing facility in Oceanside, California, that is designed and equipped to produce biologic compounds for toxicological, Phase 1 and Phase 2 clinical studies. We use the facility for the process development and manufacture of GS-6624, an investigational monoclonal antibody candidate in development for treatment of certain cancers and for fibrotic diseases, and another antibody which is currently in preclinical testing.

We have leased additional facilities to house our commercial, medical and administrative activities in Australia, Austria, Belgium, Canada, France, Germany, Greece, Hong Kong, Ireland, Italy, Netherlands, Poland, Portugal, Spain, South Korea, Sweden, Switzerland, Turkey and the United Kingdom. We also lease an office in Shanghai, China to provide sourcing and manufacturing support primarily related to our commercial purchases of active pharmaceutical ingredients.

We believe that our existing properties, including both owned and leased sites, are in good condition and suitable for the conduct of our business. We believe our capital resources are sufficient to purchase, lease or construct any additional facilities required to meet our expected long-term growth needs.

ITEM 3.

LEGAL PROCEEDINGS

In November 2008, we received notice that Teva Pharmaceuticals (Teva) submitted an abbreviated new drug application (ANDA) to the U.S. Food and Drug Administration (FDA) requesting permission to manufacture and market a generic version of Truvada. In the notice, Teva alleges that two of the patents associated with emtricitabine, owned by Emory University and licensed exclusively to us, are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Truvada. In December 2008, we filed a lawsuit in U.S. District Court in New York against Teva for infringement of the two emtricitabine patents. In March 2009, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Atripla. In the notice, Teva challenged the same two emtricitabine patents. In May 2009, we filed another lawsuit in U.S. District Court in New York against Teva for infringement of the two emtricitabine patents, and this lawsuit was consolidated with the lawsuit filed in December 2008. In January 2010, we received notice that Teva submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Viread. In the notice, Teva challenged four of the tenofovir disoproxil fumarate patents protecting Viread. In January 2010, we also received notices from Teva amending its ANDAs related to Atripla and Truvada. In the notice related to Atripla, Teva challenged four patents related to tenofovir disoproxil fumarate, two additional patents related to emtricitabine and two patents related to efavirenz. In the notice related to Truvada, Teva challenged four patents related to tenofovir disoproxil fumarate and two additional patents related to emtricitabine. In March 2010, we filed a lawsuit against Teva for infringement of the four Viread patents and two additional emtricitabine patents. In March 2010, Bristol-Myers Squibb Company and Merck & Co., Inc. filed a lawsuit against Teva for infringement of the patents related to efavirenz.

patents associated with Ranexa are invalid, unenforceable and/or will not be infringed by Lupin’s manufacture, use or sale of a generic version of Ranexa. In July 2010, we filed a lawsuit in U.S. District Court in New Jersey against Lupin for infringement of our patents for Ranexa.

In August 2010, we received notice that Sigmapharm Labs (Sigmapharm) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Hepsera. In the notice, Sigmapharm alleges that both of the patents associated with Hepsera are invalid, unenforceable and/or will not be infringed by Sigmapharm’s manufacture, use or sale of a generic version of Hepsera. In September 2010, we filed a lawsuit in U.S. District Court in New Jersey against Sigmapharm for infringement of our patents for Hepsera. One of the patents challenged by Sigmapharm is also being challenged by Ranbaxy, Inc. (Ranbaxy) pursuant to a notice received in October 2010. The patent challenged by Ranbaxy expires in July 2018. We have the option of filing a lawsuit at any time if we believe that Ranbaxy is infringing our patent.

In February 2011, we received notice that Natco Pharma Ltd. (Natco) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Tamiflu. In the notice, Natco alleges that one of the patents associated with Tamiflu is invalid, unenforceable and/or will not be infringed by Natco’s manufacture, use or sale of a generic version of Tamiflu. In March 2011, we and F. Hoffmann-La Roche Ltd. filed a lawsuit in U.S. District Court in New Jersey against Natco for infringement of the patent associated with Tamiflu.

In November 2011, we received notice that Teva submitted an Abbreviated New Drug Submission (ANDS) to the Canadian Ministry of Health requesting permission to manufacture and market a generic version of our Truvada product. In the notice, Teva alleges that three of the patents associated with Truvada are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Truvada. In January 2012, we filed a lawsuit in Canadian Federal Court against Teva seeking an order of prohibition against approval of this ANDS.

In December 2011, we received notice that Teva submitted an ANDS to the Canadian Ministry of Health requesting permission to manufacture and market a generic version of our Atripla product. In the notice, Teva alleges that three of our patents associated with Atripla and two of Merck’s patents associated with Atripla are invalid, unenforceable and/or will not be infringed by Teva’s manufacture, use or sale of a generic version of Atripla. In February 2012, we filed a lawsuit in Canadian Federal Court against Teva seeking an order of prohibition against approval of this ANDS.

We cannot predict the ultimate outcome of these actions, and we may spend significant resources enforcing and defending these patents. If we are unsuccessful in these lawsuits, some or all of our original claims in the patents may be narrowed or invalidated and the patent protection for Atripla, Truvada, Viread, Hepsera, Ranexa and Tamiflu in the United States and Atripla and Truvada in Canada could be substantially shortened. Further, if all of the patents covering those products are invalidated, the FDA could approve the requests to manufacture a generic version of such products prior to the expiration date of those patents.

In June 2011, we received a subpoena from the United States Attorney’s Office for the Northern District of California requesting documents related to the manufacture, and related quality and distribution practices, of Atripla, Emtriva, Hepsera, Letairis, Truvada, Viread and Complera. We have been cooperating and will continue to cooperate with this governmental inquiry. An estimate of a possible loss or range of losses cannot be determined given we are at the early stage of the inquiry.

We are a party to various legal actions that arose in the ordinary course of our business. We do not believe that any of these legal actions will have a material adverse impact on our consolidated business, financial position or results of operations.

ITEM 4.

MINE SAFETY DISCLOSURES

Not applicable.

PART II

ITEM 5.

MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

Our common stock is traded on The Nasdaq Global Select Market under the symbol “GILD”. The following table sets forth the high and low intra-day sale prices per share of our common stock on The Nasdaq Global Select Market for the periods indicated. These prices represent quotations among dealers without adjustments for retail mark-ups, markdowns or commissions and may not represent prices of actual transactions.


	High		Low
2011
First Quarter	$	42.90	$	36.43
Second Quarter	$	42.93	$	38.79
Third Quarter	$	43.49	$	35.28
Fourth Quarter	$	42.98	$	34.45

2010
First Quarter	$	49.50	$	42.70
Second Quarter	$	46.62	$	32.84
Third Quarter	$	36.76	$	31.73
Fourth Quarter	$	40.73	$	35.26

As of February 10, 2012, we had 757,315,361 shares of common stock outstanding held by approximately 442 stockholders of record.

We have not paid cash dividends on our common stock since our inception. We expect to retain earnings primarily for use in the operation and expansion of our business, and therefore, do not anticipate paying any cash dividends in the near future. In an effort to continue to return value to our stockholders and minimize dilution from stock issuances, in January 2011 our Board of Directors (Board) authorized a three-year $5.00 billion stock repurchase program which commenced in September 2011 upon the completion of our May 2010 stock repurchase program. We intend to use the additional authorization to repurchase our shares from time to time, to offset the dilution created by shares issued under employee stock plans and to repurchase shares. As of December 31, 2011, we have repurchased $403.1 million of our common stock under our January 2011 stock repurchase program. During 2011, we spent a total of $2.38 billion to repurchase and retire 59.9 million shares of our common stock at an average purchase price of $39.80 per share.

See Item 8, Note 13 to our Consolidated Financial Statements included in this Annual Report on Form 10-K for more information regarding our stock repurchase programs.

Performance Graph⁽¹⁾

The following graph compares our total stockholder returns for the past five years to two indices: the Standard & Poor’s 500 Stock Index, labeled S&P500 Index; and the Nasdaq Biotechnology Index, labeled NBI Index. The total return for each index assumes the reinvestment of all dividends, if any, paid by companies included in these indices and are calculated as of December 31 of each year.

We are a composite member of each of the S&P500 Index and the NBI Index, and we intend to use these indices as comparators for our stock performance for the purposes of the following graph going forward. As a composite member of the S&P500 Index, we are required under applicable regulations to use this index as a comparator, and we believe the NBI Index is a relevant comparator since it is composed of peer companies in lines-of-business similar to ours.

The stockholder return shown on the graph below is not necessarily indicative of future performance, and we do not make or endorse any predictions as to future stockholder returns.

Comparison of Cumulative Total Return on Investment for the Past Five Years⁽²⁾

LOGO

⁽¹⁾

This section is not “soliciting material,” is not deemed “filed” with the SEC and is not to be incorporated by reference in any of our filings under the Securities Act or the Exchange Act whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

⁽²⁾	Shows the cumulative return on investment assuming an investment of $100 in our common stock, the NBI Index and the S&P500 Index on December 29, 2006.

Issuer Purchases of Equity Securities

In an effort to continue to return value to our stockholders and minimize dilution from stock issuances, in January 2011 our Board authorized a three-year $5.00 billion stock repurchase program which commenced in September 2011 upon the completion of our May 2010 stock repurchase program. We intend to use the additional authorization to repurchase our shares from time to time, to offset the dilution created by shares issued under employee stock plans and to repurchase shares. As of December 31, 2011, we have repurchased $403.1 million of our common stock under our January 2011 stock repurchase program. For 2011, we spent a total of $2.38 billion to repurchase and retire 59.9 million shares of our common stock at an average purchase price of $39.80 per share.

See Item 8, Note 13 to our Consolidated Financial Statements included in this Annual Report on Form 10-K for more information regarding our stock repurchase programs.

The table below summarizes our stock repurchase activity for the three months ended December 31, 2011 (in thousands, except per share amounts):


	Total Number of Shares Purchased			Average Price Paid per Share		Total Number of Shares Purchased as Part of Publicly Announced Programs			Maximum Fair Value of Shares that May Yet Be Purchased Under the Program
October 1 – October 31, 2011		5,658		$	40.04		5,650		$	4,596,954
November 1 – November 30, 2011		37		$	40.33		—		$	4,596,954
December 1 – December 31, 2011		2		$	38.98		—		$	4,596,954

Total		5,697	⁽¹⁾	$	40.04		5,650	⁽¹⁾

⁽¹⁾	The difference between the total number of shares purchased and the total number of shares purchased as part of publicly announced programs is due to shares of common stock withheld by us from employee restricted stock awards in order to satisfy our applicable tax withholding obligations.

ITEM 6.

SELECTED FINANCIAL DATA

GILEAD SCIENCES, INC.

SELECTED CONSOLIDATED FINANCIAL DATA

(in thousands, except per share data)


	Year Ended December 31,
	2011		2010		2009		2008		2007
CONSOLIDATED STATEMENT OF INCOME DATA:
Total revenues	$	8,385,385	$	7,949,420	$	7,011,383	$	5,335,750	$	4,230,045
Total costs and expenses ⁽¹⁾	$	4,595,544	$	3,987,198	$	3,482,162	$	2,657,209	$	2,065,538
Income from operations	$	3,789,841	$	3,962,222	$	3,529,221	$	2,678,541	$	2,164,507
Provision for income taxes	$	861,945	$	1,023,799	$	876,364	$	702,363	$	635,355
Net income attributable to Gilead	$	2,803,637	$	2,901,257	$	2,635,755	$	1,978,899	$	1,584,902

Net income per share attributable to Gilead common stockholders—basic	$	3.62	$	3.39	$	2.91	$	2.15	$	1.71

Shares used in per share calculation—basic		774,903		856,060		904,604		920,693		929,133

Net income per share attributable to Gilead common stockholders—diluted	$	3.55	$	3.32	$	2.82	$	2.06	$	1.64

Shares used in per share calculation—diluted		790,118		873,396		934,109		958,825		964,356


	As of December 31,
	2011		2010		2009		2008		2007
CONSOLIDATED BALANCE SHEET DATA:
Cash, cash equivalents and marketable securities	$	9,963,972	$	5,318,071	$	3,904,846	$	3,239,639	$	2,722,422
Working capital	$	11,403,995	$	3,243,132	$	2,940,927	$	3,057,416	$	2,271,344
Total assets ⁽²⁾	$	17,303,134	$	11,592,630	$	9,698,559	$	6,936,831	$	5,731,055
Other long-term obligations	$	147,736	$	27,401	$	35,918	$	21,462	$	11,604
Convertible senior notes and unsecured senior notes ⁽³⁾	$	7,605,734	$	3,477,564	$	1,155,443	$	1,098,025	$	1,043,998
Retained earnings	$	1,776,760	$	1,183,730	$	1,995,272	$	300,314	$	198,775
Total stockholders’ equity	$	6,867,349	$	6,121,837	$	6,505,158	$	4,465,583	$	3,752,630

⁽¹⁾

During 2011, we recorded $26.6 million of impairment charges in research and development (R&D) expense related to certain in-process research and development (IPR&D) assets acquired from CGI Pharmaceuticals, Inc. See Item 8, Notes 5 and 9 to our Consolidated Financial Statements included in this Annual Report on Form 10-K.

During 2010, we recorded $136.0 million of impairment charges in R&D expense related to certain IPR&D assets acquired from CV Therapeutics, Inc. (CV Therapeutics). See Item 8, Notes 5 and 9 to our Consolidated Financial Statements included in this Annual Report on Form 10-K.

During 2008, we completed the acquisition of all of the assets of Navitas Assets, LLC related to its cicletanine business for an aggregate purchase price of $10.9 million which was allocated to purchased IPR&D.

GILEAD SCIENCES, INC.

SELECTED CONSOLIDATED FINANCIAL DATA—(Continued)

⁽²⁾	During 2009, we completed the acquisition of CV Therapeutics and we recognized consideration transferred of $1.39 billion which was primarily recorded in intangible assets. See Item 8, Note 5 to our Consolidated Financial Statements included in this Annual Report on Form 10-K.

⁽³⁾	During 2011, we issued $4.70 billion principal amount of senior unsecured notes in registered offerings. See Item 8, Note 11 to our Consolidated Financial Statements included in this Annual Report on Form 10-K.

During 2010, we issued $2.50 billion principal amount of convertible senior notes in a private placement. See Item 8, Note 11 to our Consolidated Financial Statements included in this Annual Report on Form 10-K.

ITEM 7.

MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following Management’s Discussion and Analysis of Financial Condition and Results of Operations (MD&A) is intended to help the reader understand our results of operations and financial condition. MD&A is provided as a supplement to, and should be read in conjunction with, our audited Consolidated Financial Statements and the accompanying notes to the Consolidated Financial Statements and other disclosures included in this Annual Report on Form 10-K (including the disclosures under “Item 1A. Risk Factors”). Our Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles and are presented in U.S. dollars.

Management Overview

Gilead Sciences, Inc. (Gilead, we or us), incorporated in Delaware on June 22, 1987, is a research-based biopharmaceutical company that discovers, develops and commercializes innovative medicines in areas of unmet medical need. With each new discovery and experimental drug candidate, we seek to improve the care of patients suffering from life-threatening diseases around the world. Gilead’s primary areas of focus include human immunodeficiency virus (HIV)/AIDS, liver diseases such as hepatitis B virus (HBV) and hepatitis C virus (HCV) and serious cardiovascular/metabolic and respiratory conditions. Headquartered in Foster City, California, we have operations in North America, Europe and Asia Pacific. We continue to seek to add to our existing portfolio of products through our internal discovery and clinical development programs and through a product acquisition and in-licensing strategy.

Our product portfolio is comprised of Atripla^®, Truvada^®, Viread^®, Emtriva^®, Complera^®/Eviplera^®, Hepsera^®, AmBisome^®, Letairis^®, Ranexa^®, Cayston^® and Vistide^®. In addition, we also sell and distribute certain products through our corporate partners under royalty-paying collaborative agreements. For example, F. Hoffmann-La Roche Ltd (together with Hoffmann-La Roche Inc., Roche) markets Tamiflu^®; GlaxoSmithKline Inc. (GSK) markets Hepsera and Viread in certain territories outside of the United States; GSK also markets Volibris^® outside of the United States; Astellas Pharma US, Inc. markets AmBisome in the United States and Canada; Astellas US LLC markets Lexiscan^® injection in the United States; Rapidscan Pharma Solutions, Inc. markets Rapiscan in certain territories outside of the United States; Menarini International Operations Luxembourg SA markets Ranexa in certain territories outside of the United States; and Japan Tobacco Inc. (Japan Tobacco) markets Truvada, Viread and Emtriva in Japan.

Business Highlights

During 2011, we continued to advance our pipeline and internal programs across our therapeutic areas. We augmented these efforts through strategic investments in acquisitions, in-licensing opportunities and collaborations. In the liver disease area, our acquisition of Pharmasset Inc. (Pharmasset) in early 2012 marks a significant opportunity to continue developing best-in-class drugs. We believe the combination of our existing internal research programs and our recent partnerships and acquisitions will drive research and development efforts and accelerate our product pipeline so that we can continue to bring innovative therapies to individuals around the world who are living with unmet medical needs. Below is a summary of our key accomplishments:

•

received marketing approval for and began launching Complera/Eviplera, our second single-tablet regimen for the treatment of HIV in the United States, Canada and certain countries of the European Union;

•

submitted new drug application (NDA) for “Quad” single-tablet regimen of elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate for the treatment of HIV six weeks after the Phase 3 studies concluded;

•

obtained U.S. Food and Drug Administration (FDA) agreement for a revision of the Letairis label, which subsequently changed the sales trajectory for the product;

•

progressed GS-7340, an investigational nucleotide reverse transcriptase inhibitor, and completed collaborative agreements in the HIV field which set the stage for a third generation of single-tablet regimens;

•

accelerated our timeline to develop the first all-oral HCV regimen as a result of the Pharmasset acquisition; and

•

completed the Arresto Biosciences, Inc. (Arresto) and Calistoga Pharmaceuticals, Inc. (Calistoga) acquisitions and acquired the Oceanside, California facility for biologics manufacturing to support advancing clinical studies in oncology.

New and Potential Product Offerings and New Drug Applications

In the area of HIV, we continued efforts to expand our product offerings of single-tablet regimens with the launch of Complera/Eviplera and submission of our Quad for regulatory approval in the United States and Europe. In August 2011, we received FDA approval for Complera for the treatment of HIV-1 infection in treatment-naïve adults. Complera combines three antiretroviral medications in one daily tablet—our Truvada, a fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate, and Edurant^® (rilpivirine), marketed by Tibotec Pharmaceuticals (Tibotec). In November 2011, we received marketing approval for the product in Europe, where the product is marketed as Eviplera.

In October 2011, we submitted a NDA to the FDA for the marketing approval of Quad for the treatment of HIV-1 infection in adults. Subsequently, the FDA accepted the NDA and has set a target review date of August 27, 2012 under the Prescription Drug User Fee Act (PDUFA). The FDA has indicated that a panel will be convened in May 2012 to provide expert advice on the application. We submitted the marketing authorisation application for Quad for the treatment of HIV-1 infection in adults to the European Medicines Agency in November 2011.

In December 2011, we announced that Phase 3 clinical trials of our pharmacoenhancing or “boosting” agent cobicistat, met its 48-week primary object of non-inferiority. Cobicistat increases blood levels of certain HIV medicines to allow for one pill once-daily dosing. The study indicated that after 48 weeks of treatment, 85 percent of patients taking a regimen of cobicistat-boosted atazanavir plus Truvada achieved comparable results with patients taking ritonavir-boosted atazanavir plus Truvada.

Also in December 2011, we announced Phase 3 clinical trial results showing that elvitegravir, an integrase inhibitor being evaluated for the treatment of HIV-1 infection, was non-inferior to the integrase inhibitor raltegravir after two years of therapy in treatment-experienced patients. The results of the study indicate that elvitegravir has the potential to become a new once-daily treatment option for those with HIV who have developed resistance to other therapies.

Acquisitions

In January 2011, we completed the acquisition of Arresto for $225 million plus potential future payments based on achievement of certain sales levels. Arresto was a privately-held, development-stage biotechnology company based in Palo Alto, California, focused on developing antibodies for the potential treatment of fibrotic diseases and cancer. The lead product from this acquisition was GS-6624, a humanized monoclonal antibody (mAb) targeting the human lysyl oxidase-like-2 (LOXL2) protein. In addition to ongoing Phase 2 studies of GS-6624 in liver fibrosis, myelofibrosis, colorectal cancer and pancreatic cancer, a Phase 1 study is being conducted to evaluate GS-6624 in patients with idiopathic pulmonary fibrosis.

In April 2011, we acquired Calistoga for $375 million plus potential payments of up to $225 million based on the achievement of certain milestones. Calistoga was a privately-held, biotechnology company based in Seattle, Washington, focused on the development of medicines to treat cancer and inflammatory diseases. The

portfolio of proprietary compounds from this acquisition selectively targeted isoforms of phosphoinositide-3 kinase (PI3K). Calistoga’s lead product candidate, GS-1101, was a first-in-class specific inhibitor of the PI3K delta isoform. PI3K delta is preferentially expressed in leukocytes involved in a variety of inflammatory and autoimmune diseases and hematological cancers.

In November 2011, we entered into an agreement to acquire Pharmasset for $11.1 billion. The acquisition was financed with cash on hand, bank debt and senior unsecured notes. The acquisition was completed in January 2012. Pharmasset was a clinical-stage pharmaceutical company located in Princeton, New Jersey, committed to discovering, developing and commercializing novel drugs to treat viral infections. Pharmasset’s primary focus was the development of oral therapeutics for the treatment of HCV. Pharmasset’s research and development (R&D) efforts were focused on nucleoside/tide analogs, a class of compounds that act as alternative substrates for the viral polymerase, thus inhibiting viral replication.

In-Licensing and Collaborations

In June 2011, we entered into an agreement with Tibotec for the development and commercialization of a new fixed-dose combination product containing our cobicistat and Tibotec’s protease inhibitor Prezista^® (darunavir), indicated for the treatment of HIV. Prezista is currently co-administered with ritonavir in combination with other antiretroviral agents.

In October 2011, we entered into an agreement with Boehringer Ingelheim (BI) for worldwide rights for the research, development and commercialization of BI’s novel non-catalytic site integrase inhibitors for HIV. This includes the lead compound BI 224436, which has been evaluated in a Phase 1a dose-escalation study to assess bioavailability and pharmacokinetics in healthy volunteers.

Also in October 2011, we entered into an agreement with GlobeImmune, Inc. for the license, development and commercialization of therapeutic vaccine products for use in conjunction with Viread and other oral therapies for the treatment of the chronic HBV infection.

Also in October 2011, we entered into an agreement with Bristol-Myers Squibb Company (BMS) for the licensing, development and commercialization of a fixed-dose combination containing BMS’s protease inhibitor Reyataz^® (atazanavir sulfate) and our cobicistat. We are currently studying atazanavir and cobicistat in Phase 2 and 3 studies in HIV-1 treatment-naïve patients.

In November 2011, we entered into an agreement with Tibotec for the development and commercialization of a single-tablet regimen combining Tibotec’s Prezista with our Emtriva, GS-7340 and cobicistat.

Financial Highlights

During 2011, in spite of a challenging macroeconomic environment, we continued to grow our business and achieved total product sales of $8.10 billion for 2011, an increase of 10% over 2010. The growth in product sales was primarily driven by growth in our antiviral franchise, where sales increased 8% to $7.05 billion when compared to the prior year. Sales of other products, which are comprised primarily of AmBisome, Ranexa and Letairis reached $1.05 billion, an increase of 23% compared to the prior year. Total revenues during 2011 grew 5% to $8.39 billion. Our product sales growth was partially offset by a decline in royalty revenues from our collaborations with corporate partners, which were $268.8 million for 2011, a decrease of 51% from 2010 primarily due to lower Tamiflu royalties as pandemic planning initiatives worldwide have declined. Gross margin decreased from 75% in 2010 to 74% in 2011 primarily due to an annual selling price adjustment for the percentage share of Atripla that is paid to our partner.

R&D expenses were $1.23 billion for 2011 and $1.07 billion for 2010, an increase of $156.2 million, or 15%. The increase was due primarily to costs related to clinical studies and the impact of higher headcount and

expenses associated with acquisitions, collaborations and the ongoing growth of our business. Selling, general and administrative (SG&A) expenses were $1.24 billion for 2011 and $1.04 billion for 2010, an increase of $197.6 million, or 19%. The increase was due primarily to the increased expenses associated with the ongoing growth of our business, the pharmaceutical excise tax resulting from U.S. healthcare reform and increased bad debt provision due to slower collections in certain Southern European countries.

Net income for 2011 was $2.80 billion, a 3% decrease from $2.90 billion in 2010 due primarily to the investments we made in our existing clinical programs and through acquisitions, in-licensing and collaboration agreements and lower Tamiflu royalties from Roche as a result of declining pandemic planning initiatives worldwide. Our diluted earnings per share increased by 7% to $3.55 in 2011 from $3.32 in 2010, which incorporates the impact of our share repurchases throughout the year.

Financing Activity

Cash, cash equivalents and marketable securities increased by $4.65 billion during 2011 to a total of $9.96 billion at December 31, 2011. The primary sources of cash, cash equivalents and marketable securities during 2011 were operating cash flows of $3.64 billion and $4.66 billion in proceeds from the issuance of senior unsecured notes, of which $3.67 billion was raised in December of 2011 to partially fund the Pharmasset acquisition. Key uses of cash during the year included $2.38 billion for repurchases of our common stock under our stock repurchase programs, $650.0 million for the repayment of our convertible senior notes due in 2011 and $588.6 million for acquisition activities in 2011.

During 2011, we completed our May 2010, $5.00 billion stock repurchase program and commenced share repurchases under a three-year, $5.00 billion stock repurchase program authorized by our Board of Directors in January 2011. In 2011, we spent a total of $2.38 billion of cash to repurchase and retire 59.9 million shares of our common stock at an average purchase price of $39.80 per share.

Subsequent Events

In January 2012, we raised $2.15 billion in bank debt to partially fund the acquisition of Pharmasset.

We acquired Pharmasset for $11.1 billion through a cash tender offer and subsequent merger, which closed in January 2012. Pharmasset’s lead compound was a nucleotide analog in HCV-infected individuals across genotypes now known as GS-7977. During 2012, we expect to receive a significant amount of data from clinical trials evaluating GS-7977. On February 17, 2012, we announced that data indicates that GS-7977 with ribavirin for the treatment of genotype 1 patients with a prior “null” response to an interferon-containing regimen for 12 weeks will not be sufficient to cure their disease. We are currently conducting additional Phase 2 studies in HCV infected genotype 1 patients, including treatment-naïve patients, the results of which we expect at the end of the first quarter, in the second quarter and early in the third quarter of 2012.

Outlook 2012

Our operating objectives for 2012 include increasing the market share of our commercial products, continuing to strengthen our pipeline with internally developed and/or externally in-licensed or purchased opportunities and strengthening our key alliances.

From an R&D standpoint, we will continue to execute on our pipeline development with a particular focus on innovative HIV single-tablet regimens for patients, progression of our HCV molecules into and through the clinic and new initiatives in oncology and inflammation. In 2012, we expect to publicly announce additional data sets related to the development of GS-7977 for treatment of HCV that will affect the cost and duration of our development efforts for GS-7977.

From a commercial standpoint, we have a number of internal and external initiatives intended to promote the continued growth of our franchises. In the HIV area, the scientific arguments to diagnose and treat patients earlier are strong and the reasons to use single-tablet regimens are compelling both medically and practically. The extension of the Ryan White Treatment Act should provide stable funding for AIDS Drug Assistance Programs (ADAPs) in the United States through 2013. During 2012, we will continue to roll out Complera/Eviplera around the world and, subject to FDA approval of Quad, bring our third single-tablet regimen to individuals in the U.S. living with HIV. In 2011, we launched the Truvada/rilpivirine single-tablet regimen for treatment of HIV as Complera in the United States and Canada and as Eviplera in the United Kingdom and Austria. In 2012, we expect continued uptake of Complera in the United States and Canada and to launch Eviplera throughout Europe. Our Quad is being reviewed by the FDA with a PDUFA date of August 27, 2012. Assuming approval, we expect to launch the product in September 2012. We expect Quad to contribute incremental revenue to our HIV franchise. In the HBV area, we will continue to support educational and promotional activities focused on U.S. Asian communities, highlighting the need to screen, diagnose and link patients to care. In the cardiovascular area, we will continue in our efforts to raise awareness of Gilead in the pulmonary arterial hypertension and cardiology communities and believe this will help grow revenues of Letairis and Ranexa in 2012.

We are mindful that conditions in the current macroeconomic environment could affect our ability to achieve our goals. Some of the factors that could affect our business include: future changes to healthcare reform in the United States, a continuation or worsening of global economic conditions, patent expirations of competitive products and the launch of generic competitors, continued government pricing pressures internationally and the potential volatility in foreign currency exchange rates. We will continue to monitor these conditions and will adjust our business processes, as appropriate, to mitigate these risks to our business.

We believe the successes we experienced in 2011 have enabled us to continue to build a financially sound business model that will allow us to continue to further expand our commercial and R&D activities and to maintain quality and compliance. As we continue to grow our business, we remain focused on profitable revenue growth and prudent expense management that we believe will enable solid execution of our operating objectives for 2012.

Critical Accounting Policies, Estimates and Judgments

The discussion and analysis of our financial condition and results of operations is based on our Consolidated Financial Statements, which have been prepared in accordance with U.S. generally accepted accounting principles. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. On an ongoing basis, we evaluate our estimates, including those related to revenue recognition, intangible assets, allowance for doubtful accounts, prepaid royalties, clinical trial accruals, our tax provision and stock-based compensation. We base our estimates on historical experience and on various other market specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ significantly from these estimates.

We believe the following critical accounting policies reflect the more significant judgments and estimates used in the preparation of our Consolidated Financial Statements.

Revenue Recognition

Product Sales

We recognize revenues from product sales when there is persuasive evidence that an arrangement exists, delivery to the customer has occurred, the price is fixed or determinable and collectability is reasonably assured. We record estimated reductions to revenues for government rebates such as Medicaid reimbursements, customer incentives such as cash discounts for prompt payment, distributor fees and expected returns of expired products. These estimates are deducted from gross product sales at the time such revenues are recognized. Of these reductions from gross product sales, government rebates significantly impact our reported net product sales and are based upon certain estimates that require complex and significant judgment by management.

Government Rebates

We estimate reductions to our revenues for government-managed Medicaid programs as well as to certain other qualifying federal, state and foreign government programs for the reimbursement of portions of the retail price of prescriptions filled that are covered by these programs. These reductions are settled either by us being invoiced directly or through charge-backs from our wholesalers. Government rebates that are invoiced directly to us are recorded in accrued government rebates on our Consolidated Balance Sheets. For qualified programs that can purchase our products through wholesalers at a lower contractual government price, the wholesalers charge back to us the difference between their acquisition cost and the lower contractual government price, which we record as allowances against accounts receivable. Although we may pay rebates in countries outside of the United States, to date, payments made to foreign governments have not represented a significant portion of our total government rebates. For government programs in the United States, we estimate these sales allowances based on contractual terms, historical utilization rates, new information regarding changes in these programs’ regulations and guidelines that would impact the amount of the actual rebates, our expectations regarding future utilization rates for these programs and channel inventory data obtained from our major U.S. wholesalers in accordance with our inventory management agreements. During 2011, 2010, and 2009, U.S government rebates of $1.85 billion, $1.38 billion and $885.5 million, respectively, representing 17%, 15% and 12% of total gross product sales, respectively, were deducted from gross product sales. We believe that the methodology that we use to estimate our sales allowances for government price reductions is reasonable and appropriate given the current facts and circumstances. However, actual results may differ. Based on the current information available to us, actual government rebates claimed for these periods have varied by approximately 3% from our estimates recorded in those periods. As of December 31, 2011 and 2010, we had accrued U.S. government rebates of $494.2 million and $318.3 million, respectively, in accrued government rebates and had an allowance for government chargebacks of $72.1 million and $53.5 million, respectively, recorded against accounts receivable.

The following table summarizes the aggregate activity in our U.S. government rebates allowance and accrued liabilities accounts:


	Balance at Beginning of Year		Charged to Expense			Deducted from Accruals		Balance at End of Year
Year ended December 31, 2011:
Government rebates allowances and accrued liabilities
Activity related to 2011 sales	$	—	$	1,833,926		$	1,298,281	$	535,645
Activity related to sales prior to 2011		371,783		16,877			358,039		30,621

Total	$	371,783	$	1,850,803		$	1,656,320	$	566,266

Year ended December 31, 2010:
Government rebates allowances and accrued liabilities
Activity related to 2010 sales	$	—	$	1,383,855		$	1,012,874	$	370,981
Activity related to sales prior to 2010		284,642		(8,573	)		275,267		802

Total	$	284,642	$	1,375,282		$	1,288,141	$	371,783

Intangible Assets

In conjunction with business combinations that we have completed, we have recorded intangible assets primarily related to marketed products, IPR&D projects and goodwill as part of our recognition and measurement of assets acquired and liabilities assumed in a business combination. Identifiable intangible assets, such as those related to marketed products or IPR&D projects, are measured at their respective fair values as of the acquisition date. We believe the fair values assigned to our acquired intangible assets are based on reasonable estimates and assumptions given the available facts and circumstances as of the acquisition dates. Discounted cash flow models are used in valuing these intangible assets, and these models require the use of significant estimates and assumptions including but not limited to:

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estimates of revenues and operating profits related to the products or product candidates;

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the probability of success for unapproved product candidates considering their stages of development;

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the time and resources needed to complete the development and approval of product candidates;

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the life of the potential commercialized products and associated risks, including the inherent difficulties and uncertainties in developing a product candidate such as obtaining FDA and other regulatory approvals; and

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risks related to the viability of and potential alternative treatments in any future target markets.

Goodwill represents the excess of the consideration transferred over the estimated fair values of assets acquired and liabilities assumed in a business combination. Goodwill and intangible assets determined to have indefinite useful lives are not amortized, but are required to be tested for impairment at least annually. We test goodwill and other indefinite-lived intangible assets for impairment on an annual basis and in between annual tests if we become aware of any events occurring or changes in circumstances that would indicate a reduction in the fair values of the assets below their carrying amounts. As of December 31, 2011, we had $1.27 billion of indefinite-lived intangible assets consisting of $1.00 billion of goodwill resulting from various business combinations and $266.2 million of intangible assets related to the IPR&D projects that we acquired from Arresto and Calistoga.

Intangible assets with finite useful lives are amortized over their estimated useful lives and are reviewed for impairment when facts or circumstances suggest that the carrying value of these assets may not be recoverable. We are amortizing the intangible asset related to the Ranexa product, which we acquired from CV Therapeutics, over its estimated useful life using an amortization rate derived from our forecasted future product sales for Ranexa. Our product sales forecasts are prepared annually and determined using our best estimates of future activity upon considering such factors as historical and expected future patient usage or uptake of our products, the introduction of complimentary or combination therapies or products and future product launch plans. If a previously unanticipated and significant change occurs to our sales forecasts, we will prospectively update the rate used to amortize our intangible asset related to Ranexa which may increase future cost of goods sold, as that is where we record the amortization expense. We are amortizing the intangible asset related to the Lexiscan product, which we also acquired from CV Therapeutics, over its estimated useful life to cost of goods sold on a straight-line basis. Given that current Lexiscan revenues consist of royalties received from a collaboration partner and our lack of ongoing access and visibility into that partner’s future sales forecasts, we cannot make a reasonable estimate of the amortization rate using a forecasted product sales approach. As of December 31, 2011, we had $796.7 million of net unamortized finite-lived intangible assets consisting primarily of intangible assets related to the marketed products that we acquired from CV Therapeutics.

Our judgment regarding the existence of impairment indicators is based on our historical and projected future operating results, our extent or manner of use of the acquired assets, legal and regulatory factors and events, our overall business strategy and market and economic trends. If events occur in the future that cause us to conclude that impairment indicators exist and that certain intangible assets are impaired, our financial condition and results of operations may be adversely impacted.

During the fourth quarter of 2010, we recorded $136.0 million of impairment charges related to certain IPR&D assets acquired from CV Therapeutics which we had no future plans to develop and which were deemed to have no future use to us or other market participants. These charges related to the GS-9667, Adentri and tecadenoson programs and were recorded in R&D expense. The majority of the impairment charge related to our GS-9667 program, a product candidate that was in Phase 1 clinical studies for the treatment of diabetes and hypertriglyceridemia, which was terminated in the fourth quarter of 2010 due to unfavorable results from pharmacokinetics and pharmacodynamics tests that demonstrated limited effectiveness of the compound in patients. Given these results, we do not believe it has alternative future uses for us or other market participants.

During the fourth quarter of 2011, we recorded $26.6 million of impairment charges related to certain IPR&D assets acquired from CGI. These impairment charges were a result of changes in the anticipated market share related to the Syk compound.

Allowance for Doubtful Accounts

We also maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our customers to make required payments. This allowance is based on our analysis of several factors including, but not limited to, contractual payment terms, historical payment patterns of our customers and individual customer circumstances, an analysis of days sales outstanding by geographic region and a review of the local economic environment and its potential impact on government funding and reimbursement practices. If the financial condition of our customers or the economic environment in which they operate were to deteriorate, resulting in an inability to make payments, additional allowances may be required. We believe that the allowance for doubtful accounts is adequate; however, significant deterioration in any of the above factors could materially change these expectations and may result in an increase to our allowance for doubtful accounts.

Prepaid Royalties

We capitalize royalties that we have prepaid at cost, specifically those related to the emtricitabine royalties we paid to Emory University (Emory) for the HIV indication, based on the present value of the future royalty obligation that we would expect to pay to Emory assuming certain expected future levels of our product sales incorporating emtricitabine. The present value of our future royalty obligation was derived using our weighted-average cost of capital. We review periodically the expected future sales levels of our products and any indicators that might require a write-down in the net recoverable value of our asset or a change in the estimated life of the prepaid royalty. Some potential indicators of impairment include the launch of a significant product by a competitor, significant deviations in recognized product sales compared to forecast and product safety issues and recalls.

We amortize our prepaid royalties based on an effective royalty rate that we derive from forecasted future HIV product sales incorporating emtricitabine. Our product sales forecasts are prepared annually and determined using our best estimates of future activity upon considering such factors as historical and expected future patient usage or uptake of our products, the introduction of complimentary or combination therapies or products and future product launch plans. If a previously unanticipated and significant change occurs to our sales forecasts, including the introduction of a competing product by us or one of our competitors in the same HIV market as emtricitabine, we will prospectively update the royalty rate used to amortize our prepaid royalties which may increase future cost of goods sold, as that is where we record the amortization expense. As of December 31, 2011 and 2010, we had a prepaid royalty asset relating to the emtricitabine royalties we paid to Emory of $190.2 million and $219.5 million, respectively. Amortization expense relating to this prepaid royalty asset was $29.3 million, $25.5 million and $29.9 million for the years ended December 31, 2011, 2010 and 2009, respectively.

Clinical Trial Accruals

We record accruals for estimated clinical study costs. Most of our clinical studies are performed by third-party contract research organizations (CROs). These costs are a significant component of R&D expenses. During

2011, 2010 and 2009, we incurred CRO costs of $138.0 million, $99.0 million and $109.9 million, respectively. We accrue costs for clinical studies performed by CROs over the service periods specified in the contracts and adjust our estimates, if required, based upon our ongoing review of the level of effort and costs actually incurred by the CROs. We validate our accruals quarterly with our vendors and perform detailed reviews of the activities related to our significant contracts. Based upon the results of these validation processes, we assess the appropriateness of our accruals and make any adjustments we deem necessary to ensure that our expenses reflect the actual effort incurred by the CROs.

Generally, a significant portion of the total clinical trial costs is associated with start up activities for the trial and patient enrollment. We extensively outsource our clinical trial activities and usually perform only a small portion of the start-up activities in-house. As a result, CROs typically perform most of the total start-up activities for our trials, including document preparation, site identification, screening and preparation, pre-study visits, training and program management. Start-up costs usually occur within a few months after the contract has been executed and are milestone or event driven in nature.

The remaining clinical activities and related costs, such as patient monitoring and administration, generally occur ratably throughout the life of the individual contract or study. Most contracts are negotiated as fixed per unit prices and can vary in length between three months for a single dose Phase 1 clinical study and up to two years or more for a more complex Phase 3 clinical study. The average length of contracts in 2011, 2010 and 2009 has been at the upper end of this range in order to provide long-term safety and efficacy data to support the commercial launches of Atripla, Truvada, Viread, Complera/Eviplera, Hepsera, Emtriva, Letairis and Ranexa. All of our material CRO contracts are terminable by us upon written notice and we are generally only liable for actual effort expended by the CRO and certain non-cancelable expenses incurred at any point of termination. Amounts paid in advance relating to uncompleted services will be refunded to us if a contract is terminated. Some contracts may include additional termination payments that become due and payable if we terminate the contract. Such additional termination payments are only recorded if it becomes probable that a contract will be terminated. Through December 31, 2011, differences between actual and estimated activity levels for any particular study have not been material. However, if management does not receive complete and accurate information from our vendors or underestimates activity levels associated with a study at a given point in time, we may have to record additional and potentially significant R&D expenses in future periods.

Tax Provision

We estimate our income tax provision, including deferred tax assets and liabilities, based on significant management judgment. We evaluate the realization of all or a portion of our deferred tax assets on a quarterly basis. We record a valuation allowance to reduce our deferred tax assets to the amounts that are more likely than not to be realized. We consider future taxable income, ongoing tax planning strategies and our historical financial performance in assessing the need for a valuation allowance.

If we expect to realize deferred tax assets for which we have previously recorded a valuation allowance, we will reduce the valuation allowance in the period in which such determination is first made.

Our future effective income tax rate may be affected by such factors as changes in tax laws, regulations or rates, changing interpretation of existing laws or regulations, the impact of accounting for stock-based compensation, changes in our international organization and changes in overall levels of income before tax.

We record liabilities related to uncertain tax positions in accordance with the guidance that clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements by prescribing a minimum recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. We do not believe any such uncertain tax positions currently pending will have a material adverse effect on our Consolidated Financial Statements, although an adverse resolution of one or more of these uncertain tax positions in any period could have a material impact on the results of operations for that period.

At December 31, 2011 and 2010, we had total federal, state and foreign unrecognized tax benefits of $146.9 million and $126.5 million, respectively. Of the total unrecognized tax benefits, $120.6 million and $106.5 million at December 31, 2011 and 2010, respectively, if recognized, would reduce our effective tax rate in the period of recognition. As of December 31, 2011, we believe that it is reasonably possible that our unrecognized tax benefits will not significantly change in the next 12 months as we do not expect to have clarification from the IRS and other tax authorities around any of our uncertain tax positions.

We file federal, state and foreign income tax returns in many jurisdictions in the United States and abroad. For federal income tax purposes, the statute of limitations is open for 2003 and onwards. For certain acquired entities, the statute of limitations is open for all years from inception due to our utilization of their net operating losses and credits carried over from prior years. For California income tax purposes, the statute of limitations is open for 2002 and onwards.

Our income tax returns are audited by federal, state and foreign tax authorities. We are currently under examination by the IRS for the 2008 and 2009 tax years and by various state and foreign jurisdictions. There are differing interpretations of tax laws and regulations, and as a result, significant disputes may arise with these tax authorities involving issues of the timing and amount of deductions and allocations of income among various tax jurisdictions. We periodically evaluate our exposures associated with our tax filing positions.

Stock-based Compensation

We measure all share-based payments to employees and directors, including grants of stock options, based on their relative fair values. Fair values of awards granted under our stock option plans and Employee Stock Purchase Plan were estimated at grant or purchase dates using a Black-Scholes option valuation model. The Black-Scholes option valuation model was developed for use in estimating the fair value of traded options, which have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of highly subjective assumptions, including expected stock price volatility and expected award life. Fair value of our restricted stock units (RSUs) is equal to the closing price of our common stock on the grant date. Our RSUs vest ratably on an annual basis over five years from the grant date for awards granted prior to 2011 and four years from the grant date for awards granted in 2011. We also grant performance-based restricted stock units which are valued using the Monte Carlo valuation method and vest upon the achievement of specified market and performance goals relative to a pre-determined peer group. The actual number of common shares ultimately issued is calculated by multiplying the number of performance units by a payout percentage ranging from 0% to 200%. Performance awards vest only when a committee (or subcommittee) of our Board has determined that we have achieved our specified market and performance goals.

Stock-based compensation is recognized as expense over the requisite service periods in our Consolidated Statements of Income using a graded vesting expense attribution approach for unvested stock options granted prior to January 1, 2006, and using the straight-line expense attribution approach for stock options granted after our adoption of new guidance for share-based payments to employees and directors on January 1, 2006. As stock-based compensation expenses, related to stock options recognized on adoption of the new guidance, is based on awards ultimately expected to vest, gross expense has been reduced for estimated forfeitures. The guidance requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. We estimated forfeitures based on our historical experience. Prior to the adoption of this guidance, pro forma information that was required to be disclosed included forfeitures as they occurred. As a result of the guidance adopted on January 1, 2006, we only recognize a tax benefit from stock-based compensation in additional paid-in capital (APIC) if an incremental tax benefit is realized after all other tax attributes currently available to us have been utilized. In addition, we have elected to account for the indirect benefits of stock-based compensation on the research tax credit and the extraterritorial income deduction through our Consolidated Statements of Income rather than through APIC.

During the years ended December 31, 2011, 2010 and 2009, we recognized stock-based compensation expenses of $192.4 million, $200.0 million and $185.8 million, respectively, in operating expenses, and we

capitalized $8.6 million, $10.9 million and $11.4 million, respectively, to inventory. As of December 31, 2011, 2010 and 2009, $2.0 million, $1.8 million and $1.1 million of stock-based compensation costs was included in inventory, respectively. As of December 31, 2011, we had unrecognized stock-based compensation expenses of $163.0 million related to unvested stock options, which we expect to expense over an estimated weighted-average period of 2.4 years and we had unrecognized stock-based compensation expenses of $218.9 million related to RSUs which we expect to expense over an estimated weighted average period of 3.3 years.

Results of Operations

Total Revenues

We had total revenues of $8.39 billion in 2011, $7.95 billion in 2010 and $7.01 billion in 2009. Included in total revenues were product sales, royalty revenues and contract and other revenues. Increases in total revenues were driven by growth in product sales. Total product sales were $8.10 billion in 2011, an increase of 10% over total product sales of $7.39 billion in 2010, driven primarily by our antiviral franchise, resulting from the continued growth in sales of Atripla and Truvada. The increase in product sales also reflected sales growth in our non-antiviral products, primarily AmBisome, Ranexa, Letairis and Cayston, which reached $1.05 billion mark in 2011 compared to $853.0 million in 2010. In 2011, the increase in our product sales was partially offset by a decline in our Tamiflu royalties from Roche, due to declining pandemic planning initiatives worldwide. Total product sales increased by 14% in 2010 compared to $6.47 billion in 2009, primarily driven by growth of Atripla and Truvada sales.

Product sales in the United States increased 9% for 2011 compared to 2010, primarily driven by the continued sales growth in our antiviral franchise and the introduction of Complera, partially offset by the ongoing impact of U.S. healthcare reform. The increase also reflected sales growth in non-antiviral franchises. Ranexa sales contributed $315.0 million to our 2011 product sales, an increase of 34% compared to 2010. Letairis sales contributed $293.4 million to our 2011 product sales, an increase of 22% compared to 2010. Cayston contributed $77.5 million to our 2011 product sales, an increase of 84% compared to 2010.

Product sales in Europe increased 9% for 2011 compared to 2010, primarily driven by sales growth in our antiviral franchise. This increase was partially offset by the impact of price reductions, due in part to austerity measures in certain European countries. Antiviral product sales in Europe totaled $2.71 billion in 2011, an increase of 9% compared to $2.49 billion in 2010, driven primarily by the sales of Atripla and Truvada. Foreign currency exchange, net of hedges, had an unfavorable impact on our European product sales in 2011 compared to 2010.

A significant percentage of our product sales continues to be denominated in foreign currencies and we face exposure to adverse movements in foreign currency exchange rates. We used foreign currency exchange forward and option contracts to hedge a percentage of our forecasted international sales, primarily those denominated in Euro. Foreign currency exchange, net of hedges, had a favorable impact of $21.4 million on our 2011 revenues compared to 2010 and an unfavorable impact of $93.7 million on our 2010 revenues compared to 2009.

We expect total product sales to continue to grow in 2012 as we expect to realize the full year impact related to our newest product Complera/Eviplera and expect to launch Quad in the United States in September 2012.

Product Sales

The following table summarizes the period over period changes in our product sales (in thousands):


	2011		Change			2010		Change			2009
Antiviral products:
Atripla	$	3,224,518		10	%	$	2,926,579		23	%	$	2,382,113
Truvada		2,875,141		8	%		2,649,908		6	%		2,489,682
Viread		737,867		1	%		732,240		10	%		667,510
Hepsera		144,679		(28	)%		200,592		(26	)%		271,595
Complera/Eviplera		38,747		—			—		—			—
Emtriva		28,764		4	%		27,679		(1	)%		27,974

Total antiviral products		7,049,716		8	%		6,536,998		12	%		5,838,874
AmBisome		330,156		8	%		305,856		2	%		298,597
Letairis		293,426		22	%		240,279		31	%		183,949
Ranexa		320,004		33	%		239,832		83	%		131,062
Other		109,057		63	%		66,956		298	%		16,829

Total product sales	$	8,102,359		10	%	$	7,389,921		14	%	$	6,469,311

Antiviral Products

Antiviral product sales increased by 8% in 2011 compared to 2010 and 12% in 2010 compared to 2009.

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Atripla

Atripla sales increased by 10% in 2011 compared to 2010, driven primarily by sales growth in Europe and the United States. Atripla sales increased by 23% in 2010 compared to 2009, driven primarily by sales growth in the United States and Europe where we benefited from the launch of Atripla in France in the second quarter of 2009. Atripla sales include the efavirenz component which has a gross margin of zero. The efavirenz portion of our Atripla sales was approximately $1.21 billion, $1.07 billion and $880.7 million in 2011, 2010 and 2009, respectively. Atripla sales accounted for 46%, 45% and 41% of our total antiviral product sales for 2011, 2010 and 2009, respectively.

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Truvada

Truvada sales increased by 8% in 2011 compared to 2010, driven primarily by sales growth in Europe and the United States. Truvada sales increased by 6% in 2010 compared to 2009, driven primarily by sales growth in the United States and Europe. Truvada sales accounted for 41%, 41% and 43% of our total antiviral product sales for 2011, 2010 and 2009, respectively.

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Other Antiviral Products

Other antiviral product sales, which include product sales of Viread, Hepsera, Complera/Eviplera and Emtriva, decreased by 1% in 2011 compared to 2010 due primarily to a decrease in Hepsera sales, partially offset by the launch of Complera/Eviplera following its FDA approval in August 2011 and European Commission approval in November 2011. Other antiviral product sales decreased by 1% for 2010 compared to 2009, due primarily to decreases in Hepsera sales, partially offset by sales growth of Viread.

AmBisome

Sales of AmBisome increased by 8% in 2011 compared to 2010, driven primarily by sales growth in Latin America, Canada and Europe. Sales of AmBisome increased by 2% in 2010 compared to 2009, driven primarily by sales growth in certain markets outside of the United States, partially offset by an unfavorable foreign

currency exchange impact. AmBisome product sales in the United States and Canada relate solely to our sales of AmBisome to Astellas Pharma US, Inc. which are recorded at our manufacturing cost.

Letairis

Sales of Letairis increased by 22% for 2011 compared to 2010 and 31% in 2010 compared to 2009, driven primarily by sales growth. New patient enrollments increased during 2011 following the FDA’s approval in March 2011 to remove liver toxicity language from the Boxed Warning.

Ranexa

Sales of Ranexa increased by 33% for 2011 compared to 2010 and 83% for 2010 compared to 2009, driven primarily by sales growth.

Royalty Revenues

The following table summarizes the period over period changes in our royalty revenues (in thousands):


	2011		Change			2010		Change			2009
Royalty revenues	$	268,827		-51	%	$	545,970		11	%	$	491,818

Historically, our most significant source of royalty revenues has been from sales of Tamiflu by Roche. We recognize royalties on Tamiflu sales by Roche in the quarter following the quarter in which Tamiflu sales are recognized by Roche.

Royalty revenues declined 51% for 2011 compared to 2010, due primarily to lower Tamiflu royalties from Roche. Royalty revenues increased 11% for 2010 compared to 2009, driven primarily by increase in other royalty revenues, which include royalties from GSK for Hepsera, royalties from Astellas US LLC for Lexiscan and royalties from Japan Tobacco for Truvada, partially offset by the lower Tamiflu royalties from Roche. Tamiflu royalties since the second quarter of 2010 have been decreasing due to declining pandemic planning initiatives worldwide. Tamiflu royalties from Roche contributed $75.5 million, $386.5 million and $392.7 million to total royalty revenues in 2011, 2010 and 2009 respectively.

Cost of Goods Sold and Product Gross Margin

The following table summarizes the period over period changes in our product sales (in thousands), cost of goods sold (in thousands) and product gross margin:


	2011			Change			2010			Change			2009
Total product sales	$	8,102,359			10	%	$	7,389,921			14	%	$	6,469,311
Cost of goods sold	$	2,124,410			14	%	$	1,869,876			17	%	$	1,595,558
Product gross margin		74	%					75	%					75	%

Our product gross margin for 2011 was 74%, a decrease of 1% compared to 2010, due primarily to an annual selling price adjustment for the percentage share of Atripla that is paid to our partner. Our product gross margin for 2010 was 75%, consistent with our product gross margin for 2009.

We expect our product gross margin in 2012 to be lower compared to 2011, due primarily to product mix as we expect a higher proportion of Atripla sales partially offset by an increase in product gross margin related to the full year impact of sales of Complera/Eviplera and the anticipated launch of Quad in September 2012.

Research and Development Expenses

We manage our R&D expenses by identifying the research and development activities we anticipate will be performed during a given period and then prioritizing efforts based on scientific data, probability of successful development, market potential, available human and capital resources and other similar considerations. We continually review our R&D pipeline and the status of development and, as necessary, reallocate resources among the R&D portfolio that we believe will best support the future growth of our business.

The following table summarizes the period over period changes in our R&D expenses (in thousands):


	2011		Change			2010		Change			2009
Research and development	$	1,229,151		15	%	$	1,072,930		14	%	$	939,918

R&D expenses summarized above consist primarily of personnel costs, including salaries, benefits and stock-based compensation, clinical studies performed by CROs, materials and supplies, licenses and fees, milestone payments under collaboration arrangements and overhead allocations consisting of various support and facilities-related costs. The following table provides a breakout of R&D expenses by major cost type (in thousands):


	2011		2010		2009
Clinical studies and outside services	$	570,302	$	375,228	$	413,487
Personnel expenses		412,463		384,488		364,505
Impairment and restructuring charges		26,716		135,800		2,200
Other		219,670		177,414		159,726

Total	$	1,229,151	$	1,072,930	$	939,918

R&D expenses for 2011 increased by $156.2 million, or 15%, compared to 2010, due primarily to a $195.1 million increase in clinical studies and outside services related to study progression in liver disease and HIV, new investments in oncology and inflammation and new in-license agreements, milestones and ongoing collaborations, a $28.0 million increase in personnel expenses due to higher headcount, an increase in other expenses including research and process development manufacturing to support clinical studies and the ongoing growth of our business, partially offset by a decrease in impairment charges.

R&D expenses in 2010 increased by $133.0 million, or 14%, compared to 2009, due primarily to impairment charges of $136.0 million that we recorded related to IPR&D assets acquired from CV Therapeutics, $23.5 million of clinical studies expenses related to increased HIV research activities and $16.1 million of compensation and benefits expenses. The majority of the impairment charge related to our GS-9667 program, a product candidate that was in Phase 1 clinical studies for the treatment of diabetes and hypertriglyceridemia, which was terminated in the fourth quarter of 2010 due to unfavorable results from pharmacokinetics and pharmacodynamics tests that demonstrated limited effectiveness of the compound in patients. Given these results, we do not believe it has alternative future uses for us or other market participants. The increase in R&D expenses was partially offset by $37.0 million due to the timing of certain clinical studies and $30.3 million of lower R&D expense reimbursement related to our collaboration with Tibotec.

In 2012, we expect R&D expenses to increase over 2011 levels due to continued investment in our internal and collaborative R&D efforts as we anticipate that some of our product candidates will progress into more advanced phases of clinical studies as well as adding more clinical development programs to our pipeline.

Selling, General and Administrative Expenses

The following table summarizes the period over period changes in our SG&A expenses (in thousands):


	2011		Change			2010		Change			2009
Selling, general and administrative	$	1,241,983		19	%	$	1,044,392		10	%	$	946,686

SG&A expenses are comprised primarily of compensation and benefits associated with sales and marketing, finance, human resources, legal and other administrative personnel; facilities and overhead costs; outside marketing, advertising and legal expenses and other general and administrative costs.

SG&A expenses in 2011 increased by $197.6 million or 19%, compared to 2010, due primarily to increased contract, legal and other professional services of $86.8 million, pharmaceutical excise tax of $47.3 million resulting from U.S. healthcare reform, increased compensation and benefits expenses of $41.6 million as a result of higher headcount to support our expanding commercial activities, promotional costs of $20.1 million driven by our expanding sales and marketing activities and bad debt provisions of $14.7 million associated with slower collections in southern European countries.

SG&A expenses in 2010 increased by $97.7 million or 10%, compared to 2009, due primarily to increased compensation and benefits expenses of $36.3 million as a result of higher headcount to support our expanding commercial activities, increased contract and professional services expenses of $27.3 million driven primarily by our expanding sales and marketing activities and $18.1 million related to facilities and equipment expenses.

In 2012, we expect SG&A expenses to increase over 2011 levels due to increased investments supporting the continued growth in all of our franchises and the increase in the U.S. pharmaceutical excise tax. We believe we have the appropriate SG&A infrastructure to support the growth of our business in 2012.

Restructuring Expenses

During the second quarter of 2010, we approved and communicated a plan to close our research operations in Durham, North Carolina and consolidate our liver disease research activities in Foster City, California. We believe this plan will allow our employees to collaborate more effectively and further advance our programs in the liver disease area. In 2010, we recorded a total of $14.6 million and $10.4 million of restructuring expenses in SG&A and R&D expenses, respectively, related to employee severance and facilities-related expenses under this plan. In December 2010, we closed our operations in Durham. We have not incurred and do not expect to incur any additional significant costs in connection with this plan.

During the second quarter of 2009, we approved a plan to realize certain synergies as a result of the CV Therapeutics acquisition by re-aligning our cardiovascular operations and eliminating redundancies. In 2010, we recorded $10.6 million and $3.4 million in restructuring expenses in SG&A and R&D expenses, respectively, related to employee severance, relocation, lease termination costs and other facilities-related expenses. In 2011, we recorded $6.7 million in restructuring expenses in SG&A related to other facilities-related expenses. Total costs incurred under this plan were $43.5 million and $29.1 million in SG&A and R&D expenses, respectively. We have not incurred and do not expect to incur any additional significant costs in connection with this plan.

Interest and Other Income, Net

We recorded interest and other income, net, of $66.6 million, $60.3 million and $42.4 million in 2011, 2010 and 2009, respectively. The increase in interest and other income, net, in 2011 compared to 2010 was driven primarily by a favorable net foreign currency exchange impact and an increase in interest income, partially offset by an increase in costs related to our hedging activities. The increase in interest and other income, net, in 2010 compared to 2009 was driven primarily by decreased costs related to our hedging activities.

We expect interest income to decrease in 2012 as we spent cash, cash equivalents and marketable securities to partially fund our Pharmasset acquisition which closed in January 2012.

Interest Expense

Our interest expense was $205.4 million, $109.0 million and $69.7 million in 2011, 2010 and 2009, respectively. The increase in interest expense in 2011 compared to 2010 was due primarily to the issuance of our convertible senior notes for $2.50 billion in July 2010, the issuance of our senior unsecured notes for $1.00 billion in March 2011, the issuance of our senior unsecured notes for $3.70 billion in December 2011 and bridge financing associated with our acquisition of Pharmasset. This 2011 increase was partially offset by the maturity of our convertible senior notes due in May 2011, which had an aggregate principal balance of $650.0 million. The increase in interest expense in 2010 compared to 2009 was due primarily to the issuance of our senior convertible notes for $2.50 billion in July 2010.

We expect interest expense to increase in 2012 due to the additional debt we issued in connection with our acquisition of Pharmasset, which included the $3.70 billion in senior unsecured notes issued in December 2011 and $2.15 billion in bank debt we raised subsequent to December 31, 2011.

Provision for Income Taxes

Our provision for income taxes was $861.9 million, $1.02 billion and $876.4 million in 2011, 2010 and 2009 respectively. The 2011 effective tax rate of 23.6% differed from the U.S. federal statutory rate of 35% due primarily to tax credits and certain operating earnings from non-U.S. subsidiaries that are considered indefinitely invested outside the United States, partially offset by state taxes and the non-deductible pharmaceutical excise tax. We do not provide for U.S. income taxes on undistributed earnings of our foreign operations that are intended to be permanently reinvested.

The 2010 effective tax rate of 26.2% differed from the U.S. federal statutory rate of 35% due primarily to tax credits and certain operating earnings from non-U.S. subsidiaries that are considered indefinitely invested outside the United States, partially offset by state taxes.

The 2009 effective tax rate of 25.0% differed from the U.S. federal statutory rate of 35% due primarily to tax credits, the resolution of certain tax positions with tax authorities and certain operating earnings from non-U.S. subsidiaries that are considered indefinitely invested outside the United States, partially offset by state taxes and the revaluation of certain state tax assets related to the integration of CV Therapeutics.

Liquidity and Capital Resources

We believe that our existing capital resources, supplemented by our cash flows generated from operating activities, will be adequate to satisfy our capital needs for the foreseeable future. Our cash, cash equivalents and marketable securities increased significantly in the fourth quarter of 2011 as we issued senior unsecured notes for total net proceeds of $3.67 billion to fund our $11.1 billion acquisition of Pharmasset, which closed in January 2012. Below is additional information describing our cash, cash equivalents and marketable securities, working capital and primary sources and uses of cash.

The following table summarizes our cash, cash equivalents and marketable securities, our working capital and our cash flow activities as of the end of, and for each of, the periods presented (in thousands):


	2011		2010			2009
As of December 31:
Cash, cash equivalents and marketable securities	$	9,963,972	$	5,318,071		$	3,904,846
Working capital	$	11,403,995	$	3,243,132		$	2,940,927

Year Ended December 31:
Cash provided by (used in):
Operating activities	$	3,639,010	$	2,833,913		$	3,080,054
Investing activities	$	3,589,845	$	(1,937,751	)	$	(2,215,900	)
Financing activities	$	1,763,569	$	(1,338,710	)	$	(1,051,438	)

Cash, Cash Equivalents and Marketable Securities

Cash, cash equivalents and marketable securities totaled $9.96 billion at December 31, 2011, an increase of $4.65 billion or 87% from December 31, 2010. This increase was primarily attributable to the issuance of our senior unsecured notes in 2011 for total net proceeds of $4.66 billion and cash provided by operations of $3.64 billion. This increase was partially offset by $2.38 billion used to repurchases of our common stock under our stock repurchase programs, $650.0 million used to repay our convertible senior notes due in May 2011 and $588.6 million used in our recent acquisitions of Arresto and Calistoga. The net proceeds related to our senior unsecured notes issued in December 2011 were used to fund our acquisition of Pharmasset in January 2012.

Cash, cash equivalents and marketable securities totaled $5.32 billion at December 31, 2010, an increase of $1.41 billion or 36% from December 31, 2009. This increase was primarily attributable to net cash provided by operations of $2.83 billion and net proceeds of $2.46 billion from the issuance of our convertible senior notes in 2010, partially offset by $4.02 billion used to repurchase our common stock under our stock repurchase programs.

Working Capital

Working capital was $11.40 billion at December 31, 2011. The increase of $8.16 billion or 251% from working capital as of December 31, 2010 was primarily attributable to:

•

an increase of $7.80 billion in cash, cash equivalents and short-term marketable securities resulting from the $3.67 billion issuance of senior unsecured notes in December 2011 and sales of long-term marketable securities in anticipation of the acquisition of Pharmasset; and

•

a decrease of $644.8 million in the current portion of long-term debt and other obligations, net, due primarily to the repayment of our convertible senior notes due in May 2011.

Working capital was $3.24 billion at December 31, 2010, an increase of $302.2 million or 10% from working capital as of December 31, 2009. This increase was primarily attributable to:

•

an increase of $441.7 million in cash, cash equivalents and short-term marketable securities;

•

an increase of $232.4 million in accounts receivable, net, primarily driven by increased product sales; and

•

an increase of $152.0 million in inventories, due primarily to the purchase of efavirenz at its estimated net selling price from BMS.

This increase was partially offset by an increase of $640.8 million in the current portion of convertible senior notes, net and other long-term obligations, due to the reclassification of our convertible senior notes due in May 2011 to current liabilities.

Cash Provided by Operating Activities

Cash provided by operating activities of $3.64 billion in 2011 primarily related to net income of $2.79 billion, adjusted for non-cash items such as $302.2 million of depreciation and amortization expenses, $192.4 million of stock-based compensation expenses, $64.1 million of deferred income taxes and $220.3 million of net cash inflow related to changes in operating assets and liabilities. This was partially offset by $40.8 million of excess tax benefits from stock option exercises which we reclassified to cash used in financing activities.

Cash provided by operating activities of $2.83 billion in 2010 primarily related to net income of $2.89 billion, adjusted for non-cash items such as $265.5 million of depreciation and amortization expenses, $200.0 million of stock-based compensation expenses, $136.0 million of IPR&D impairment expenses and $82.1 million of tax benefits from employee stock plans, partially offset by $680.4 million of net cash outflow related to changes in operating assets and liabilities and $81.6 million of excess tax benefits from stock option exercises which we reclassified to cash used in financing activities.

Cash provided by operating activities of $3.08 billion in 2009 primarily related to net income of $2.63 billion, adjusted for non-cash items such as $180.7 million of stock-based compensation expenses and $148.4 million of amortization expenses.

Cash Provided by (Used in) Investing Activities

Cash provided by investing activities in 2011 was $3.59 billion, consisting of a net proceeds of $4.31 billion related to the sales of marketable securities in connection with our acquisition of Pharmasset, partially offset by $588.6 million used in our acquisitions of Arresto and Calistoga and $131.9 million of capital expenditures.

Cash used in investing activities in 2010 was $1.94 billion, driven by a net use of $1.78 billion in purchases of marketable securities, $91.0 million used in our acquisition of CGI and $61.9 million of capital expenditures.

Cash used in investing activities in 2009 was $2.22 billion, driven by cash used for our acquisition of CV Therapeutics of $1.25 billion (net of cash acquired), a net use of $738.0 million in purchases of marketable securities and $230.1 million of capital expenditures for the year. Capital expenditures in 2009 included the purchase of an office building and approximately 30 acres of land located in Foster City, California.

Cash Provided by (Used in) Financing Activities

Cash provided by financing activities in 2011 was $1.76 billion, driven primarily by the issuance of $4.66 billion in senior unsecured notes, of which $3.67 billion was raised in December 2011 to partially fund the Pharmasset acquisition, net of issuance costs and $211.7 million in proceeds from issuances of common stock under our employee stock plans. The cash proceeds were partially offset by $2.38 billion used to repurchase our common stock under our stock repurchase programs, including commissions and $650.0 million used to repay our convertible senior notes due in May 2011.

Cash used in financing activities in 2010 was $1.34 billion, driven primarily by the $4.02 billion used to repurchase our common stock under our stock repurchase programs and $362.6 million used to purchase note hedges related to our convertible senior notes due in May 2014 and May 2016. The cash outflows were partially offset by $2.46 billion in net proceeds from the issuance of such notes, $155.4 million in proceeds from the sale of warrants related to such notes and $221.2 million in proceeds from issuances of common stock under our employee stock plans.

Cash used in financing activities in 2009 was $1.05 billion, driven primarily by the $998.5 million used to repurchase our common stock under our stock repurchase program and the $305.5 million used to extinguish the convertible senior notes assumed from the acquisition of CV Therapeutics. The cash outflows were partially offset by proceeds of $222.7 million from issuances of common stock under our employee stock plans.

During 2011, we completed our May 2010, three-year, $5.00 billion stock repurchase program at which time we initiated purchases under our January 2011, three-year, $5.00 billion stock repurchase program. Under the completed program, we repurchased and retired a total of 135.5 million shares of our common stock at an average purchase price of $36.89 per share. As of December 31, 2011, the remaining authorized amount of stock repurchases that may be made under the repurchase program was $4.60 billion.

Long-Term Debt

We were eligible to borrow up to an aggregate of $1.25 billion in revolving credit loans under an amended and restated credit agreement. The credit agreement also included a sub-facility for swing-line loans and letters of credit. As of December 31, 2011, we had $4.0 million in letters of credit outstanding under the $1.25 billion credit agreement. In January 2012, we fully repaid the outstanding obligations under this credit agreement, at which time this credit agreement was terminated.

On January 12, 2012, in conjunction with our acquisition of Pharmasset, we entered into a five-year $1.25 billion revolving credit facility credit agreement (the Five-Year Revolving Credit Agreement), a $750.0 million short-term revolving credit facility credit agreement (the Short-Term Revolving Credit Agreement) and a $1.00 billion Term Loan Facility (the Term Loan Credit Agreement). We borrowed an aggregate principal amount of $2.15 billion as follows: $750.0 million under the Five-Year Revolving Credit Agreement, $400.0 million under the Short-Term Revolving Credit Agreement and $1.00 billion under the Term Loan Credit Agreement, upon the close of the acquisition.

All three credit agreements contain customary representations, warranties, affirmative, negative and financial maintenance covenants and events of default. These loans will bear interest at either (i) the Eurodollar Rate plus the Applicable Margin or (ii) the Base Rate plus the Applicable Margin, each as defined in the applicable credit agreement. We may reduce the commitments and may prepay loans under any of these agreements in whole or in part at any time without premium or penalty.

The Five-Year Revolving Credit Agreement was inclusive of a $30.0 million swing line loan sub-facility and a $25.0 million letter of credit sub-facility. The Five-Year Revolving Credit Agreement will terminate and all amounts owing thereunder shall be due and payable on January 12, 2017. The Short-Term Revolving Credit Agreement will terminate and all amounts owing thereunder shall be due and payable on January 10, 2013; however, we may request that the maturity date be extended until January 9, 2014. All principal repayment installments under the Term Loan Credit Agreement will be due and payable as specified in the Term Loan Credit Agreement, with the final principal installment payment due and payable on January 12, 2015.

In December 2011, we issued senior unsecured notes in a registered offering for an aggregate principal amount of $3.70 billion to partially fund our acquisition of Pharmasset. The notes will pay interest at fixed annual rates ranging from 2.40% to 5.65%.

Our convertible senior notes due in May 2011 matured and we repaid the aggregate principal balance of $650.0 million. We also paid $36.1 million in cash related to the conversion spread of our matured notes, which represent the conversion value in excess of the principal amount, and received $36.1 million in cash from the related convertible note hedges. Warrants related to our convertible senior notes due in May 2011 expired in August 2011.

In March 2011, we issued senior unsecured notes due in April 2021 in a registered offering for an aggregate principal amount of $1.00 billion. The notes will pay interest at a fixed annual rate of 4.50%.

We believe that our existing capital resources, supplemented by cash generated from our operations, will be adequate to satisfy our capital needs for the foreseeable future. Our future capital requirements will depend on many factors, including but not limited to the following:

•

the commercial performance of our current and future products;

•

the progress and scope of our R&D efforts, including preclinical studies and clinical trials;

•

the cost, timing and outcome of regulatory reviews;

•

the expansion of our sales and marketing capabilities;

•

administrative expenses;

•

the possibility of acquiring additional manufacturing capabilities or office facilities;

•

the possibility of acquiring other companies or new products;

•

the establishment of additional collaborative relationships with other companies; and

•

costs associated with the defense, settlement and adverse results of litigation and government investigations.

We may in the future require additional funding, which could be in the form of proceeds from equity or debt financings. If such funding is required, we cannot assure that it will be available to us on favorable terms, if at all.

Off Balance Sheet Arrangements

We do not have any off balance sheet arrangements.

Contractual Obligations

Our contractual obligations consist of debt obligations, operating leases, capital commitments, purchase obligations for active pharmaceutical ingredients and inventory-related items and clinical trials contracts. The following table summarizes our significant enforceable and legally binding obligations, future commitments and obligations related to all contracts that we are likely to continue regardless of the fact that certain of these obligations may be cancelable as of December 31, 2011 (in thousands):


	Payments due by Period
Contractual Obligations	Total		Less than one year		1-3 years		3-5 years		More than 5 years
Long-term debt⁽¹⁾	$	10,811,866	$	232,724	$	3,102,973	$	2,336,169	$	5,140,000
Operating lease obligations		204,954		43,635		66,329		41,775		53,215
Capital commitments⁽²⁾		16,556		16,556		—		—		—
Purchase obligations⁽³⁾⁽⁴⁾		1,317,922		990,151		202,471		125,300		—
Clinical trials⁽⁵⁾		191,043		124,473		64,872		1,698		—

Total	$	12,542,341	$	1,407,539	$	3,436,645	$	2,504,942	$	5,193,215

⁽¹⁾

Long-term debt obligations include future interest payments based on fixed rates of 0.625%, 1.00% and 1.625% for our convertible senior notes due in May 2013, May 2014 and May 2016, respectively. Long-term debt obligations also include future interest payments based on fixed rates of 2.40%, 3.05%, 4.50% 4.40% and 5.65% for our senior unsecured notes due in December 2014, December 2016, April 2021, December 2021 and December 2041, respectively. At December 31, 2011, the aggregate carrying values of our convertible notes and senior unsecured notes were $2.92 billion and $4.68 billion, respectively.

⁽²⁾	At December 31, 2011, we had firm capital project commitments of approximately $16.6 million primarily relating to facilities improvement projects.

⁽³⁾	At December 31, 2011, we had firm purchase commitments related to active pharmaceutical ingredients and certain inventory-related items. These amounts include minimum purchase requirements and actual purchases are expected to significantly exceed these amounts.

⁽⁴⁾

In addition to the above, we have committed to make potential future milestone payments to third parties as part of licensing, collaboration and development arrangements. Payments under these agreements generally become due and payable only upon achievement of certain developmental, regulatory and/or commercial milestones. Because the achievement of these milestones is neither probable nor reasonably estimable, such contingencies have not been recorded on our Consolidated Balance Sheets and have not been included in the table above.

⁽⁵⁾

At December 31, 2011, we had several clinical studies in various clinical trial phases. Our most significant clinical trial expenditures are to CROs. Although all of our material contracts with CROs are cancelable, we historically have not cancelled such contracts. These amounts reflect commitments based on existing contracts and do not reflect any future modifications to, or terminations of, existing contracts or anticipated or potential new contracts.

We had total gross unrecognized tax benefit liabilities of $170.6 million as of December 31, 2011. We believe that it is reasonably possible that our unrecognized tax benefits will not significantly change in the next 12 months as we do not expect to have clarification from the IRS and other tax authorities around any of our uncertain tax positions. The unrecognized tax benefits were included in long-term income taxes payable and non-current deferred tax assets on our Consolidated Balance Sheet and have not been included in the table above.

Recent Accounting Pronouncements

In May 2011, the Financial Accounting Standards Board (FASB) issued amendments to its existing standard for fair value measurement to achieve common guidance between U.S. generally accepted accounting principles and International Financial Reporting Standards. In addition, the amended standard revises certain requirements for measuring fair value and for disclosure around fair value measurement. It does not require additional fair value measurements and was not intended to establish valuation standards or affect valuation practices outside of financial reporting. The updated standard is effective for us beginning in the first quarter of 2012. Early adoption is not permitted. The adoption of these amendments will not have a material impact on our Consolidated Financial Statements.

In June 2011, the FASB issued an update to an existing standard for comprehensive income to make the presentation of items within other comprehensive income (OCI) more prominent. The updated standard prohibits the current presentation of OCI in the statement of stockholders’ equity and instead, provides public companies the option of presenting OCI in a continuous statement of comprehensive income or as two separate consecutive statements. Additionally, the update requires that reclassification adjustments be displayed on the face of the financial statements where OCI is reported. In December 2011, the FASB issued another update that indefinitely deferred the specific requirement of presenting reclassification adjustments out of OCI in both net income and OCI on the face of the financial statements. During the deferral period, the existing requirements for the presentation of reclassification adjustments must continue to be followed. The updated standard is effective for us beginning in the first quarter of 2012. Upon adoption, the updated standard will impact the presentation of our Consolidated Financial Statements; however, it will have no impact on our financial position or results of operations.

In September 2011, the FASB issued new accounting guidance intended to simplify goodwill impairment testing. Entities will be allowed to perform a qualitative assessment on goodwill impairment to determine whether a quantitative assessment is necessary. This guidance is effective for goodwill impairment tests performed in interim and annual periods for fiscal years beginning after December 15, 2011. The standard is effective for us beginning in the first quarter of 2012. The adoption of this guidance will not have a material impact on our Consolidated Financial Statements.

In December 2011, the FASB issued a new standard to address the disclosure requirements around offsetting financial and derivative instruments and their related arrangements to enable users of financial statements to understand the effect of those arrangements on a company’s financial position. The update requires companies to disclose both the net and gross amounts of the relevant assets and liabilities that are offset in the notes to the financial statements. The updated standard is effective for us beginning in the first quarter of 2013 and will be applied retrospectively for all comparative periods presented. We believe that the adoption of this standard will not have a material impact on our Consolidated Financial Statements.

ITEM 7A.

QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Foreign Currency Exchange Risk

Our operations include manufacturing and sales activities in the United States, Canada and Ireland as well as sales activities in countries outside the United States, including Europe and Asia Pacific. As a result, our financial results could be significantly affected by factors such as changes in foreign currency exchange rates or weak economic conditions in the foreign markets in which we distribute our products. Our operating results are exposed to changes in foreign currency exchange rates between the U.S. dollar and various foreign currencies, the most significant of which is the Euro. When the U.S. dollar strengthens against these currencies, the relative value of sales made in the respective foreign currency decreases. Conversely, when the U.S. dollar weakens against these currencies, the relative amounts of such sales increase. Overall, we are a net receiver of foreign currencies and, therefore, benefit from a weaker U.S. dollar and are adversely affected by a stronger U.S. dollar relative to those foreign currencies in which we transact significant amounts of business.

A significant percentage of our product sales are denominated in foreign currencies. We enter into foreign currency exchange forward and option contracts to partially mitigate the impact of changes in currency exchange rates on net cash flows from our foreign currency denominated sales. We also hedge certain monetary assets and liabilities denominated in foreign currencies, which reduces but does not eliminate our exposure to currency fluctuations between the date a transaction is recorded and the date that cash is collected or paid. In general, the market risks of these contracts are offset by corresponding gains and losses on the transactions being hedged.

The following table summarizes the notional amounts, weighted-average currency exchange rates and fair values of our open foreign currency exchange forward contracts at December 31, 2011. We had no foreign currency exchange option contracts outstanding at December 31, 2011. All contracts have maturities of 18 months or less. Weighted-average rates are stated in terms of the amount of U.S. dollars per foreign currency. Fair values represent estimated settlement amounts at December 31, 2011 and 2010 (notional amounts and fair values in U.S. dollars and in thousands):

Foreign Currency Exchange Forward Contracts


	December 31, 2011							December 31, 2010
Currency	Notional Amount		Weighted-Average Settlement Price		Fair Value			Notional Amount		Weighted-Average Settlement Price		Fair Value
Euro	$	3,205,266		1.34	$	86,942		$	2,763,277		1.33	$	43,854
British Pound		305,314		1.57		4,030			313,380		1.55		2,133
Canadian Dollar		179,785		0.99		1,904			183,276		0.97		(5,669	)
Australian Dollar		129,025		0.98		(3,356	)		112,145		0.95		(8,494	)
Swiss Franc		110,161		1.10		2,532			82,765		0.99		(4,935	)
Danish Krone		1,520		0.16		(170	)		29,532		0.18		690
Swedish Krone		31,738		0.15		531			30,266		0.14		(881	)
Norwegian Krone		17,898		0.17		428			18,871		0.17		(272	)
New Zealand Dollar		9,304		0.75		(217	)		10,035		0.74		(507	)
Turkish Lira		10,539		0.52		(7	)		10,539		0.64		(11	)
Polish Zloty		25,532		0.32		2,148			435		0.33		(0	)

Total	$	4,026,082			$	94,765		$	3,554,521			$	25,908

Interest Rate Risk

Our portfolio of available-for-sale marketable securities and our fixed and variable rate liabilities create an exposure to interest rate risk. With respect to our investment portfolio, we adhere to an investment policy that requires us to limit amounts invested in securities based on credit rating, maturity, industry group and investment type and issuer, except for securities issued by the U.S. government. The goals of our investment policy, in order of priority, are as follows:

•

safety and preservation of principal and diversification of risk;

•

liquidity of investments sufficient to meet cash flow requirements; and

•

competitive after-tax rate of return.

The following table summarizes the expected maturities and average interest rates of our interest-generating assets and interest-bearing liabilities at December 31, 2011 (dollars in thousands):


																					Total Fair Value at December 31, 2011
	Years Ending December 31,
	2012			2013			2014			2015			2016			Thereafter			Total
Assets
Available-for-sale debt securities	$	1,574,140		$	26,100		$	—		$	—		$	—		$	51,500		$	1,651,740	$	1,616,664
Average interest rate		1.2	%		101.2	%		0.0	%		0.0	%		0.0	%		0.8	%
Liabilities
Long-term debt⁽¹⁾	$	—		$	649,867		$	2,000,000		$	—		$	1,950,000		$	3,250,000		$	7,849,867	$	8,522,542
Average interest rate		0.0	%		0.6	%		1.5	%		0.0	%		2.1	%		4.8	%

⁽¹⁾

In April 2006, we issued convertible senior notes due in May 2013 in a private placement pursuant to Rule 144A of the Securities Act of 1933, as amended. The notes were issued at par and bear interest rates of 0.625%, and may be converted into shares of our common stock subject to certain circumstances.

In July 2010, we issued convertible senior notes due in May 2014 and May 2016 in a private placement pursuant to Rule 144A of the Securities Act of 1933, as amended. The notes due in May 2014 and May 2016 were issued at par and bear interest rates of 1.00% and 1.625%, respectively, and may be converted into shares of our common stock subject to certain circumstances.

In March 2011, we issued senior unsecured notes due in April 2021 in a registered offering. The notes pay interest at a fixed annual rate of 4.50%.

In December 2011, we issued senior unsecured notes due in December 2014, 2016, 2021 and 2041 in a registered offering. The notes pay interest at fixed annual rates ranging from 2.40% to 5.65%.

In connection with funding our $11.1 billion acquisition of Pharmasset, we liquidated approximately $4.34 billion of our investment portfolio in late 2011. The proceeds of the sales were reinvested in money market funds which totaled $7.46 billion as of December 31, 2011. As interest rate risk for money market funds is low, we have excluded the balance from the table of interest rate sensitive instruments above. We continue to invest our existing portfolio in securities with a similar profile, however, the amounts invested are generally smaller and have a shorter investment horizon.

Credit Risk

As of December 31, 2011, we held approximately $47.0 million of auction rate securities within our available-for-sale long-term marketable securities. Our auction rate securities comprised less than 1% of our total

cash, cash equivalents and marketable securities as of December 31, 2011. In 2008, we began observing the failed auctions for our auction rate securities for which the underlying assets are comprised of student loans. Most of our auction rate securities, including those subject to the failed auctions, are currently rated AAA, consistent with the high quality rating required by our investment policy, are supported by the federal government as part of the Federal Family Education Loan Program and are over-collateralized. Our auction rate securities reset every seven to 14 days with maturity dates ranging from 2025 through 2040 and have annual interest rates ranging from 0.18% to 0.80%. As of December 31, 2011, our auction rate securities continued to earn interest.

If auctions continue to fail for securities in which we have invested, we may be unable to liquidate some or all of our auction rate securities at par should we need or desire to access the funds invested in those securities. However, based on our expected operating cash flows as well as access to funds through our credit facility, we believe that we will be able to hold these securities until there is a recovery in the auction market and the related securities, which may be at final maturity. As a result, we do not anticipate that the current illiquidity of these auction rate securities will have a material effect on our cash requirements or working capital.

As of December 31, 2011, we held Greek government-issued bonds with an estimated fair value of approximately $24.7 million within our available-for-sale long-term marketable securities. In 2010, the Greek government agreed to settle the majority of its aged outstanding accounts receivable with zero-coupon bonds. Currently, these bonds trade infrequently on the open market at a substantial discount to the face value. We believe we will be able to hold these securities until maturity. As a result, we do not anticipate that the illiquidity of these securities will have a material effect on our cash requirements or working capital.

In light of the volatility and developments that we have seen in the financial markets, we continue to review our cash equivalents and marketable securities carefully and strive to invest prudently. We believe that maintaining the primary goals of our investment policy, safety and preservation of principal and diversification of risk, as well as liquidity, has helped protect us from many of the risks in the credit markets while allowing us to continue to meet our operating cash flow requirements as well as execute on other strategic opportunities.

We are also subject to credit risk from our accounts receivable related to our product sales. Our accounts receivable balance at December 31, 2011 was $1.95 billion, compared to $1.62 billion at December 31, 2010. The majority of our trade accounts receivable arises from product sales in the United States and Europe. As of December 31, 2011, our accounts receivables in Southern Europe, specifically Greece, Italy, Portugal and Spain totaled approximately $1.10 billion, of which $612.4 million were greater than 120 days past due and $250.7 million were greater than 365 days past due.

ITEM 8.

FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

The financial statements required by this item are set forth beginning at page 96 of this Annual Report on Form 10-K and are incorporated herein by reference.

ITEM 9.

CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

Not applicable.

ITEM 9A.

CONTROLS AND PROCEDURES

(a) Evaluation of Disclosure Controls and Procedures

An evaluation as of December 31, 2011 was carried out under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, of the effectiveness of our “disclosure controls and procedures,” which are defined in Rule 13a-15(e) under the Securities Exchange Act of

1934, as amended (the Exchange Act), as controls and other procedures of a company that are designed to ensure that the information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the Securities and Exchange Commission’s rules and forms, and that such information is accumulated and communicated to the company’s management, including its Chief Executive Officer and Chief Financial Officer, as appropriate, to allow timely decisions regarding required disclosure. Based upon that evaluation, our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective at December 31, 2011.

(b) Management’s Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rule 13a-15(f) of the Exchange Act. Our internal control system is designed to provide reasonable assurance regarding the preparation and fair presentation of financial statements for external purposes in accordance with generally accepted accounting principles. All internal control systems, no matter how well designed, have inherent limitations and can provide only reasonable assurance that the objectives of the internal control system are met.

Under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, we conducted an evaluation of the effectiveness of our internal control over financial reporting, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). Based on our evaluation, we concluded that our internal control over financial reporting was effective as of December 31, 2011.

Our independent registered public accounting firm, Ernst & Young LLP, has audited our Consolidated Financial Statements included in this Annual Report on Form 10-K and have issued a report on the effectiveness of our internal control over financial reporting as of December 31, 2011. Their report on the audit of internal control over financial reporting appears below.

Our management, including our Chief Executive Officer and Chief Financial Officer, has evaluated any changes in our internal control over financial reporting that occurred during the quarter ended December 31, 2011, and has concluded that there was no change during such quarter that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting. We completed the implementation of a new Enterprise Resource Planning (ERP) system during the fourth quarter of 2011. This implementation was not undertaken in response to any identified deficiency or weakness to our internal controls over financial reporting. It was undertaken to establish a scalable foundation for our core business processes.

ITEM 9B.

OTHER INFORMATION

Not applicable.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors and Stockholders of Gilead Sciences, Inc.

We have audited Gilead Sciences, Inc.’s internal control over financial reporting as of December 31, 2011, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (the COSO criteria). Gilead Sciences, Inc.’s management is responsible for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control Over Financial Reporting. Our responsibility is to express an opinion on the company’s internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, Gilead Sciences, Inc. maintained, in all material respects, effective internal control over financial reporting as of December 31, 2011, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the 2011 consolidated financial statements of Gilead Sciences, Inc. and our report dated February 23, 2012 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Redwood City, California

February 23, 2012

PART III

ITEM 10.

DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

The information required by this Item concerning our directors and executive officers is incorporated by reference to the sections of our Definitive Proxy Statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with our 2012 Annual Meeting of Stockholders (the Proxy Statement) under the headings “Nominees,” “Qualification of Nominees,” “Board Committees and Meetings,” “Executive Officers,” and “Section 16(a) Beneficial Ownership Reporting Compliance.”

Our written Code of Ethics applies to all of our directors and employees, including our executive officers, including without limitation our principal executive officer, principal financial officer, principal accounting officer or controller or persons performing similar functions. The Code of Ethics is available on our website at http://www.gilead.com in the Investors section under “Corporate Governance.” Changes to or waivers of the Code of Ethics will be disclosed on the same website. We intend to satisfy the disclosure requirement under Item 5.05 of Form 8-K regarding any amendment to, or waiver of, any provision of the Code of Ethics by disclosing such information on the same website.

ITEM 11.

EXECUTIVE COMPENSATION

The information required by this Item is incorporated by reference to the sections of the Proxy Statement under the headings “Executive Compensation,” “Compensation Committee Interlocks and Insider Participation,” “Compensation Committee Report,” and “Compensation of Non-Employee Board Members.”

ITEM 12.

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

The information required by this Item is incorporated by reference to the sections of the Proxy Statement under the headings “Security Ownership of Certain Beneficial Owners and Management” and “Securities Authorized for Issuance under Equity Compensation Plans.”

ITEM 13.

CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

The information required by this Item is incorporated by reference to the sections of the Proxy Statement under the headings “Nominees,” and “Certain Relationships and Related Party Transactions.”

ITEM 14.

PRINCIPAL ACCOUNTANT FEES AND SERVICES

The information required by this Item is incorporated by reference to the section of the Proxy Statement under the heading “Principal Accountant Fees and Services.”

PART IV

ITEM 15.

EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

(a) The following documents are filed as part of this Annual Report on Form 10-K:

(1) Index list to Consolidated Financial Statements:


Report of Independent Registered Public Accounting Firm			95

Audited Consolidated Financial Statements:

Consolidated Balance Sheets			96

Consolidated Statements of Income			97

Consolidated Statements of Stockholders’ Equity			98

Consolidated Statements of Cash Flows			99

Notes to Consolidated Financial Statements			100

(2) Schedule II is included on page 152 of this report. All other schedules are omitted because they are not required or the required information is included in the financial statements or notes thereto.

(3) Exhibits.

The following exhibits are filed herewith or incorporated by reference:


Exhibit Footnote	Exhibit Number	Description of Document
(1)	2.1	Agreement and Plan of Merger among Registrant, Apex Merger Sub, Inc. and CV Therapeutics, Inc., dated as of March 12, 2009

±+(2)	2.2	Agreement and Plan of Merger among Registrant, Cougar Merger Sub, Inc. and CGI Pharmaceuticals, Inc., dated as of June 23, 2010

≠+(3)	2.3	Agreement and Plan of Merger among Registrant, Arroyo Merger Sub, Inc. and Arresto Biosciences, Inc., dated as of December 19, 2010

‡+(4)	2.4	Agreement and Plan of Merger among Registrant, Gilead Biopharmaceutics Ireland Corporation, Gilead Sciences Limited, Calistoga Pharmaceuticals, Inc. and Shareholder Representative Services LLC, as Stockholders’ Agent, dated as of February 21, 2011

+(4)	2.6	Amendment No. 1 to the Agreement and Plan of Merger among Registrant, Gilead Biopharmaceutics Ireland Corporation, Hot Springs Acquisition Corp., Calistoga Pharmaceuticals, Inc. and Shareholder Representative Services LLC, as Stockholders’ Agent, entered into as of March 24, 2011

†(5)	2.5	Agreement and Plan of Merger among Registrant, Merger Sub and Pharmasset, Inc. dated as of November 21, 2011

(6)	3.1	Restated Certificate of Incorporation of Registrant, as amended through May 12, 2011

(7)	3.2	Certificate of Designation of the Series A Junior Participating Preferred Stock of Registrant

(8)	3.3	Certificate of Amendment to Certificate of Designation of Series A Junior Participating Preferred Stock of Registrant

(6)	3.4	Amended and Restated Bylaws of Registrant, as amended and restated on May 12, 2011

	4.1	Reference is made to Exhibit 3.1, Exhibit 3.2, Exhibit 3.3 and Exhibit 3.4

(9)	4.2	Amended and Restated Rights Agreement between Registrant and ChaseMellon Shareholder Services, LLC, dated October 21, 1999


Exhibit Footnote	Exhibit Number	Description of Document
(10)	4.3	First Amendment to Amended and Restated Rights Agreement between Registrant and Mellon Investor Services, LLC (formerly known as ChaseMellon Shareholder Services, LLC), dated October 29, 2003

(11)	4.4	Second Amendment to Amended and Restated Rights Agreement between Registrant and Mellon Investor Services, LLC (formerly known as ChaseMellon Shareholder Services, LLC), dated May 11, 2006

(12)	4.5	Indenture related to the Convertible Senior Notes, due 2013, between Registrant and Wells Fargo Bank, National Association, as trustee (including form of 0.625% Convertible Senior Note due 2013), dated April 25, 2006

(13)	4.6	Indenture related to the Convertible Senior Notes, due 2014, between Registrant and Wells Fargo Bank, National Association, as trustee (including form of 1.00% Convertible Senior Note due 2014), dated July 30, 2010

(13)	4.7	Indenture related to the Convertible Senior Notes, due 2016, between Registrant and Wells Fargo Bank, National Association, as trustee (including form of 1.625% Convertible Senior Note due 2016), dated July 30, 2010

(14)	4.8	Indenture, dated as of March 30, 2011, between Registrant and Wells Fargo, National Association, as Trustee

(14)	4.9	First Supplemental Indenture, dated as of March 30, 2011, between Registrant and Wells Fargo, National Association, as Trustee

(14)	4.10	Form of Note (included in Exhibit 4.9 above)

(15)	4.11	Second Supplemental Indenture, dated as of December 13, 2011, between Registrant and Wells Fargo, National Association, as Trustee

(15)	4.12	Form of 2014 Note (included in Exhibit 4.11 above)

(15)	4.13	Form of 2016 Note (included in Exhibit 4.11 above)

(15)	4.14	Form of 2021 Note (included in Exhibit 4.11 above)

(15)	4.15	Form of 2041 Note (included in Exhibit 4.11 above)

(16)	10.1	Confirmation of OTC Convertible Note Hedge related to 2013 Notes, dated April 19, 2006, as amended and restated as of April 24, 2006, between Registrant and Bank of America, N.A.

(16)	10.2	Confirmation of OTC Warrant Transaction, dated April 19, 2006, as amended and restated as of April 24, 2006, between Registrant and Bank of America, N.A. for warrants expiring in 2013

(2)	10.3	Confirmation of OTC Convertible Note Hedge related to 2014 Notes, dated July 26, 2010, between Registrant and Goldman, Sachs & Co.

(2)	10.4	Confirmation of OTC Convertible Note Hedge related to 2014 Notes, dated July 26, 2010, between Registrant and JPMorgan Chase Bank, National Association

(2)	10.5	Confirmation of OTC Convertible Note Hedge related to 2016 Notes, dated July 26, 2010, between Registrant and Goldman, Sachs & Co.

(2)	10.6	Confirmation of OTC Convertible Note Hedge related to 2016 Notes, dated July 26, 2010, between Registrant and JPMorgan Chase Bank, National Association

(2)	10.7	Confirmation of OTC Warrant Transaction, dated July 26, 2010, between Registrant and Goldman, Sachs & Co. for warrants expiring in 2014

(2)	10.8	Confirmation of OTC Warrant Transaction, dated July 26, 2010, between Registrant and JPMorgan Chase Bank, National Association for warrants expiring in 2014


Exhibit Footnote	Exhibit Number	Description of Document
(2)	10.9	Confirmation of OTC Warrant Transaction, dated July 26, 2010, between Registrant and Goldman, Sachs & Co. for warrants expiring in 2016

(2)	10.10	Confirmation of OTC Warrant Transaction, dated July 26, 2010, between Registrant and JPMorgan Chase Bank, National Association for warrants expiring in 2016

(17)	10.11	Confirmation of OTC Additional Convertible Note Hedge related to 2014 Notes, dated August 5, 2010, between Registrant and Goldman, Sachs & Co.

(17)	10.12	Confirmation of OTC Additional Convertible Note Hedge related to 2014 Notes, dated August 5, 2010, between Registrant and JPMorgan Chase Bank, National Association

(17)	10.13	Confirmation of OTC Additional Convertible Note Hedge related to 2016 Notes, dated August 5, 2010, between Registrant and Goldman, Sachs & Co.

(17)	10.14	Confirmation of OTC Additional Convertible Note Hedge related to 2016 Notes, dated August 5, 2010, between Registrant and JPMorgan Chase Bank, National Association

(17)	10.15	Confirmation of OTC Additional Warrant Transaction, dated August 5, 2010, between Registrant and Goldman, Sachs & Co. for warrants expiring in 2014

(17)	10.16	Confirmation of OTC Additional Warrant Transaction, dated August 5, 2010, between Registrant and JPMorgan Chase Bank, National Association for warrants expiring in 2014

(17)	10.17	Confirmation of OTC Additional Warrant Transaction, dated August 5, 2010, between Registrant and Goldman, Sachs & Co. for warrants expiring in 2016

(17)	10.18	Confirmation of OTC Additional Warrant Transaction, dated August 5, 2010, between Registrant and JPMorgan Chase Bank, National Association for warrants expiring in 2016

(17)	10.19	Amendment to Confirmation of OTC Convertible Note Hedge related to 2014 Notes, dated August 30, 2010, between Registrant and Goldman, Sachs & Co.

(17)	10.20	Amendment to Confirmation of OTC Convertible Note Hedge related to 2014 Notes, dated August 30, 2010, between Registrant and JPMorgan Chase Bank, National Association

(17)	10.21	Amendment to Confirmation of OTC Convertible Note Hedge related to 2016 Notes, dated August 30, 2010, between Registrant and Goldman, Sachs & Co.

(17)	10.22	Amendment to Confirmation of OTC Convertible Note Hedge related to 2016 Notes, dated August 30, 2010, between Registrant and JPMorgan Chase Bank, National Association

(17)	10.23	Amendment to Confirmation of OTC Additional Convertible Note Hedge related to 2014 Notes, dated August 30, 2010, between Registrant and Goldman, Sachs & Co.

(17)	10.24	Amendment to Confirmation of OTC Additional Convertible Note Hedge related to 2014 Notes, dated August 30, 2010, between Registrant and JPMorgan Chase Bank, National Association

(17)	10.25	Amendment to Confirmation of OTC Additional Convertible Note Hedge related to 2016 Notes, dated August 30, 2010, between Registrant and Goldman, Sachs & Co.

(17)	10.26	Amendment to Confirmation of OTC Additional Convertible Note Hedge related to 2016 Notes, dated August 30, 2010, between Registrant and JPMorgan Chase Bank, National Association

(18)	10.27	5-Year Revolving Credit Facility Credit Agreement among Registrant and Gilead Biopharmaceutics Ireland Corporation, as Borrowers, Bank of America, N.A., as Administrative Agent, Swing Line Lender and L/C Issuer, certain other lenders parties thereto, Barclays Capital, as Syndication Agent, and Goldman Sachs Bank USA, JPMorgan Chase Bank, N.A., Royal Bank of Canada and Wells Fargo Bank, N.A., as Co-Documentation Agents, dated as of January 12, 2012


Exhibit Footnote	Exhibit Number	Description of Document
(18)	10.28	Short-Term Revolving Credit Facility Credit Agreement, among Registrant and Gilead Biopharmaceutics Ireland Corporation, as Borrowers, Bank of America, N.A., as Administrative Agent, certain other lenders parties thereto, Barclays Capital, as Syndication Agent, and Goldman Sachs Bank USA, JPMorgan Chase Bank, N.A., Royal Bank of Canada and Wells Fargo Bank, N.A., as Co-Documentation Agents, dated as of January 12, 2012

(18)	10.29	Term Loan Facility Credit Agreement, among Registrant, as Borrower, Bank of America, N.A., certain other lenders parties thereto, Barclays Capital, as Syndication Agent, and Goldman Sachs Bank USA, JPMorgan Chase Bank, N.A., Royal Bank of Canada and Wells Fargo Bank, N.A., as Co-Documentation Agents, dated as of January 12, 2012

(18)	10.30	Parent Guaranty Agreement (5-Year Revolving Credit Facility), dated as of January 12, 2012, by Registrant

(18)	10.31	Parent Guaranty Agreement (Short-Term Revolving Credit Facility), dated as of January 12, 2012, by Registrant

*(19)	10.32	Gilead Sciences, Inc. 1991 Stock Option Plan, as amended through January 29, 2003

*(20)	10.33	Form of option agreements used under the 1991 Stock Option Plan

*(19)	10.34	Gilead Sciences, Inc. 1995 Non-Employee Directors’ Stock Option Plan, as amended through January 30, 2002

*(21)	10.35	Form of option agreement used under the Gilead Sciences, Inc. 1995 Non-Employee Directors’ Stock Option Plan

*(22)	10.36	Gilead Sciences, Inc. 2004 Equity Incentive Plan, as amended through May 6, 2009

*(23)	10.37	Form of employee stock option agreement used under 2004 Equity Incentive Plan (for grants prior to February 2008)

*(24)	10.38	Form of employee stock option agreement used under 2004 Equity Incentive Plan (for grants made February 2008 through April 2009)

*(25)	10.39	Form of employee stock option agreement used under 2004 Equity Incentive Plan (for grants commencing in May 2009)

*(26)	10.40	Form of employee stock option agreement used under 2004 Equity Incentive Plan (for grants commencing in February 2010)

*(4)	10.41	Form of employee stock option agreement used under 2004 Equity Incentive Plan (for 2011 and subsequent year grants)

*(24)	10.42	Form of non-employee director stock option agreement used under 2004 Equity Incentive Plan (for grants prior to 2008)

*(24)	10.43	Form of non-employee director option agreement used under 2004 Equity Incentive Plan (for initial grants made in 2008)

*(24)	10.44	Form of non-employee director option agreement used under 2004 Equity Incentive Plan (for annual grants made in May 2008)

*(25)	10.45	Form of non-employee director option agreement used under 2004 Equity Incentive Plan (for annual grants commencing in May 2009)

*(25)	10.46	Form of restricted stock unit issuance agreement used under 2004 Equity Incentive Plan (for annual grants to non-employee directors commencing in May 2009)

*(25)	10.47	Form of restricted stock award agreement used under 2004 Equity Incentive Plan (for annual grants to certain non-employee directors)

*(27)	10.48	Form of performance share award agreement used under the 2004 Equity Incentive Plan (for grants made in 2007)


Exhibit Footnote	Exhibit Number	Description of Document
*(28)	10.49	Form of performance share award agreement used under the 2004 Equity Incentive Plan (for grants made in 2008)

*(25)	10.50	Form of performance share award agreement used under the 2004 Equity Incentive Plan (for grants made in 2009)

*(26)	10.51	Form of performance share award agreement used under the 2004 Equity Incentive Plan (for grants made in 2010)

*(4)	10.52	Form of performance share award agreement used under the 2004 Equity Incentive Plan (for 2011)

*(29)	10.53	Form of restricted stock unit issuance agreement used under the 2004 Equity Incentive Plan (for grants made prior to May 2009)

*(25)	10.54	Form of restricted stock unit issuance agreement used under the 2004 Equity Incentive Plan (for grants commencing in May 2009)

*(30)	10.55	Form of restricted stock unit issuance agreement used under the 2004 Equity Incentive Plan (service-based vesting for executive officers commencing in November 2009)

*(4)	10.56	Form of restricted stock unit issuance agreement used under the 2004 Equity Incentive Plan (for 2011)

*(26)	10.57	Gilead Sciences, Inc. Employee Stock Purchase Plan, amended and restated on November 3, 2009

*(31)	10.58	Gilead Sciences, Inc. International Employee Stock Purchase Plan, adopted November 3, 2009

*(32)	10.59	Gilead Sciences, Inc. Deferred Compensation Plan—Basic Plan Document

*(32)	10.60	Gilead Sciences, Inc. Deferred Compensation Plan—Adoption Agreement

*(32)	10.61	Addendum to the Gilead Sciences, Inc. Deferred Compensation Plan

*(33)	10.62	Gilead Sciences, Inc. 2005 Deferred Compensation Plan, as amended and restated on October 23, 2008

*(26)	10.63	Gilead Sciences, Inc. Severance Plan, as amended on December 14, 2009

*(23)	10.64	Gilead Sciences, Inc. Corporate Bonus Plan

*(6)	10.65	Amended and Restated Gilead Sciences, Inc. Code Section 162(m) Bonus Plan

*(34)	10.66	2012 Base Salaries for the Named Executive Officers

*(35)	10.67	Offer Letter dated April 16, 2008 between Registrant and Robin Washington

*(20)	10.68	Form of Indemnity Agreement entered into between Registrant and its directors and executive officers

*(20)	10.69	Form of Employee Proprietary Information and Invention Agreement entered into between Registrant and certain of its officers and key employees

*(26)	10.70	Form of Employee Proprietary Information and Invention Agreement entered into between Registrant and certain of its officers and key employees (revised in September 2006)

+(36)	10.71	Amended and Restated Collaboration Agreement by and among Registrant, Gilead Holdings, LLC, Bristol-Myers Squibb Company, E.R. Squibb & Sons, L.L.C., and Bristol-Myers Squibb & Gilead Sciences, LLC, dated September 28, 2006

+(24)	10.72	Commercialization Agreement by and between Gilead Sciences Limited and Bristol-Myers Squibb Company, dated December 10, 2007


Exhibit Footnote	Exhibit Number	Description of Document
+(37)	10.73	Amendment Agreement, dated October 25, 1993, between Registrant, the Institute of Organic Chemistry and Biochemistry (IOCB) and Rega Stichting v.z.w. (REGA), together with the following exhibits: the License Agreement, dated December 15, 1991, between Registrant, IOCB and REGA (the 1991 License Agreement), the License Agreement, dated October 15, 1992, between Registrant, IOCB and REGA (the October 1992 License Agreement) and the License Agreement, dated December 1, 1992, between Registrant, IOCB and REGA (the December 1992 License Agreement)

(38)	10.74	Amendment Agreement between Registrant and IOCB/REGA, dated December 27, 2000 amending the 1991 License Agreement and the December 1992 License Agreement

(36)	10.75	Sixth Amendment Agreement to the License Agreement, between IOCB/REGA and Registrant, dated August 18, 2006 amending the October 1992 License Agreement and the December 1992 License Agreement

+(36)	10.76	Development and License Agreement among Registrant and F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc., dated September 27, 1996

+(39)	10.77	First Amendment and Supplement dated November 15, 2005 to the Development and Licensing Agreement between Registrant, F. Hoffmann-La Roche Ltd and Hoffman-La Roche Inc. dated September 27, 1996

+	10.78	Second Amendment dated December 22, 2011 to the Development and Licensing Agreement between Registrant, F. Hoffmann-La Roche Ltd and Hoffman-La Roche Inc. dated September 27, 1996

+(40)	10.79	Exclusive License Agreement between Registrant (as successor to Triangle Pharmaceuticals, Inc.), Glaxo Group Limited, The Wellcome Foundation Limited, Glaxo Wellcome Inc. and Emory University, dated May 6, 1999

+(41)	10.80	Royalty Sale Agreement by and among Registrant, Emory University and Investors Trust & Custodial Services (Ireland) Limited, solely in its capacity as Trustee of Royalty Pharma, dated July 18, 2005

+(41)	10.81	Amended and Restated License Agreement between Registrant, Emory University and Investors Trust & Custodial Services (Ireland) Limited, solely in its capacity as Trustee of Royalty Pharma, dated July 21, 2005.

+(42)	10.82	License Agreement between Japan Tobacco Inc. and Registrant, dated March 22, 2005

+(43)	10.83	First Amendment to License Agreement between Japan Tobacco Inc. and Registrant, dated May 19, 2005

+(43)	10.84	Second Amendment to License Agreement between Japan Tobacco Inc. and Registrant, dated May 17, 2010

+(43)	10.85	Third Amendment to License Agreement between Japan Tobacco Inc. and Registrant, dated July 5, 2011

+(43)	10.86	Fourth Amendment to License Agreement between Japan Tobacco Inc. and Registrant, dated July 5, 2011

+(44)	10.87	License Agreement between Registrant (as successor to Myogen, Inc.) and Abbott Deutschland Holding GmbH dated October 8, 2001

+(44)	10.88	License Agreement between Registrant (as successor to CV Therapeutics, Inc.) and Syntex (U.S.A.) Inc., dated March 27, 1996

+(45)	10.89	First Amendment to License Agreement between Registrant (as successor to CV Therapeutics, Inc.) and Syntex (U.S.A.) Inc., dated July 3, 1997

(45)	10.90	Amendment No. 2 to License Agreement between Registrant (as successor to CV Therapeutics, Inc.) and Syntex (U.S.A.) Inc., dated November 30. 1999


Exhibit Footnote	Exhibit Number	Description of Document
+(46)	10.91	Amendment No. 4 to License Agreement with Registrant (as successor to CV Therapeutics, Inc.) and Roche Palo Alto LLC (successor in interest by merger to Syntex (U.S.A.) Inc.), dated June 20, 2006

+	10.92	Amendment No. 5 to License Agreement with Registrant (as successor to CV Therapeutics, Inc.) and Roche Palo Alto LLC (successor in interest by merger to Syntex (U.S.A.) Inc.), dated December 22, 2011

+(47)	10.93	License and Collaboration Agreement by and among Registrant, Gilead Sciences Limited and Tibotec Pharmaceuticals, dated July 16, 2009

+(43)	10.94	Second Amendment to License and Collaboration Agreement by and among Registrant, Gilead Sciences Limited and Tibotec Pharmaceuticals, dated July 1, 2011

+(48)	10.95	Master Clinical and Commercial Supply Agreement between Gilead World Markets, Limited, Registrant and Patheon Inc., dated January 1, 2003

+(41)	10.96	Tenofovir Disoproxil Fumarate Manufacturing Supply Agreement by and between Gilead Sciences Limited and PharmaChem Technologies (Grand Bahama), Ltd., dated July 17, 2003

+(49)	10.97	Addendum to Tenofovir Disoproxil Fumarate Manufacturing Supply Agreement by and between Gilead Sciences Limited and PharmaChem Technologies (Grand Bahama) Ltd., dated May 10, 2007

+(33)	10.98	Addendum to Tenofovir Disoproxil Fumarate Manufacturing Supply Agreement by and between Gilead Sciences Limited and PharmaChem Technologies (Grand Bahama) Ltd., dated December 5, 2008

+(4)	10.99	Addendum to Tenofovir Disoproxil Fumarate Manufacturing Supply Agreement by and between Gilead Sciences Limited and PharmaChem Technologies (Grand Bahama) Ltd., dated February 3. 2011

+(3)	10.100	Tenofovir Disoproxil Fumarate Manufacturing Supply Agreement by and between Gilead Sciences Limited and Ampac Fine Chemicals LLC, dated November 3, 2010

+(39)	10.101	Restated and Amended Toll Manufacturing Agreement between Gilead Sciences Limited, Registrant and Nycomed GmbH (formerly ALTANA Pharma Oranienburg GmbH), dated November 7, 2005

+(16)	10.102	Emtricitabine Manufacturing Supply Agreement between Gilead Sciences Limited and Evonik Degussa GmbH (formerly known as Degussa AG), dated June 6, 2006

+(2)	10.103	Amendment No. 1 to Emtricitabine Manufacturing Supply Agreement between Gilead Sciences Limited and Evonik Degussa GmbH (formerly known as Degussa AG), dated April 30, 2010

(33)	10.104	Purchase and Sale Agreement and Escrow Instructions between Electronics for Imaging, Inc. and Registrant, dated October 23, 2008

	21.1	Subsidiaries of Registrant

	23.1	Consent of Independent Registered Public Accounting Firm

	24.1	Power of Attorney, reference is made to the signature page

	31.1	Certification of Chief Executive Officer, as required by Rule 13a-14(a) or Rule 15d-14(a) of the Securities Exchange Act of 1934, as amended

	31.2	Certification of Chief Financial Officer, as required by Rule 13a-14(a) or Rule 15d-14(a) of the Securities Exchange Act of 1934, as amended

	32.1**	Certifications of Chief Executive Officer and Chief Financial Officer, as required by Rule 13a-14(b) or Rule 15d-14(b) and Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. §1350)


Exhibit Footnote	Exhibit Number	Description of Document

	101***	The following materials from Registrant’s Annual Report on Form 10-K for the year ended December 31, 2011, formatted in Extensible Business Reporting Language (XBRL) includes: (i) Consolidated Balance Sheets at December 31, 2011 and 2010, (ii) Consolidated Statements of Income for the years ended December 31, 2011, 2010 and 2009, (iii) Consolidated Statements of Stockholders’ Equity for the years ended December 31, 2011, 2010 and 2009, (iv) Consolidated Statements of Cash Flows for years ended December 31, 2011, 2010 and 2009, and (v) Notes to Consolidated Financial Statements.

(1)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on March 12, 2009, and incorporated herein by reference.

(2)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2010, and incorporated herein by reference.

(3)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2010, and incorporated herein by reference.

(4)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2011, and incorporated herein by reference.

(5)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on November 25, 2011, and incorporated herein by reference.

(6)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on May 17, 2011, and incorporated herein by reference.

(7)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on November 22, 1994, and incorporated herein by reference.

(8)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on May 11, 2006, and incorporated herein by reference.

(9)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on October 22, 1999, and incorporated herein by reference.

(10)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on October 31, 2003, and incorporated herein by reference.

(11)	Filed as an exhibit to Registrant’s Registration Statement on Form S-8 (No. 333-135412) filed on June 28, 2006, and incorporated herein by reference.

(12)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on April 25, 2006, and incorporated herein by reference.

(13)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on August 2, 2010, and incorporated herein by reference.

(14)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on April 1, 2011, and incorporated herein by reference.

(15)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on December 13, 2011, and incorporated herein by reference.

(16)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2006, and incorporated herein by reference.

(17)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2010, and incorporated herein by reference.

(18)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on January 17, 2012, and incorporated herein by reference.

(19)	Filed as an exhibit to Registrant’s Registration Statement on Form S-8 (No. 333-102912) filed on January 31, 2003, and incorporated herein by reference.

(20)	Filed as an exhibit to Registrant’s Registration Statement on Form S-1 (No. 33-55680), as amended, and incorporated herein by reference.

(21)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K/A for the fiscal year ended December 31, 1998, and incorporated herein by reference.

(22)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on May 11, 2009, and incorporated herein by reference.

(23)	Filed as an exhibit to Registrant’s Current Report on Form 8-K/A filed on February 22, 2006, and incorporated herein by reference.

(24)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2007, and incorporated herein by reference.

(25)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2009, and incorporated herein by reference.

(26)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2009, and incorporated herein by reference.

(27)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2006, and incorporated herein by reference.

(28)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2008, and incorporated herein by reference.

(29)	Filed as an exhibit to Registrant’s Current Report on Form 8-K first filed on December 19, 2007, and incorporated herein by reference.

(30)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2010, and incorporated herein by reference.

(31)	Filed as an exhibit to Registrant’s Registration Statement on Form S-8 (No. 333-163871) filed on December 21, 2009, and incorporated herein by reference.

(32)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2001, and incorporated herein by reference.

(33)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2008, and incorporated herein by reference.

(34)	Information is included in Registrant’s Current Report on Form 8-K filed on February 1, 2012, and incorporated herein by reference.

(35)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2008, and incorporated herein by reference.

(36)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2006, and incorporated herein by reference.

(37)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended March 31, 1994, and incorporated herein by reference.

(38)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2000, and incorporated herein by reference.

(39)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2005, and incorporated herein by reference.

(40)	Filed as an exhibit to Triangle Pharmaceuticals, Inc.’s Quarterly Report on Form 10-Q/A filed on November 3, 1999, and incorporated herein by reference.

(41)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2005, and incorporated herein by reference.

(42)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2005, and incorporated herein by reference.

(43)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2011, and incorporated herein by reference.

(44)	Filed as an exhibit to Myogen, Inc.’s Registration Statement on Form S-1 (No. 333-108301), as amended, originally filed on August 28, 2003, and incorporated herein by reference.

(45)	Filed as an exhibit to CV Therapeutics, Inc.’s Registration Statement on Form S-3 (No. 333-59318), as amended, originally filed on April 20, 2001, and incorporated herein by reference.

(46)	Filed as an exhibit to CV Therapeutics, Inc.’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2006, and incorporated herein by reference.

(47)	Filed as an exhibit to Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2009, and incorporated herein by reference.

(48)	Filed as an exhibit to Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2003, and incorporated herein by reference.

(49)	Filed as an exhibit to Registrant’s Current Report on Form 8-K filed on August 7, 2007, and incorporated herein by reference.

The Agreement and Plan of Merger (the Merger Agreement) contains representations and warranties of Registrant, Cougar Merger Sub, Inc. and CGI Pharmaceuticals, Inc. made solely to each other as of specific dates. Those representations and warranties were made solely for purposes of the Merger Agreement and may be subject to important qualifications and limitations agreed to by Registrant, Cougar Merger Sub, Inc. and CGI Pharmaceuticals, Inc. Moreover, some of those representations and warranties may not be accurate or complete as of any specified date, may be subject to a standard of materiality provided for in the Merger Agreement and have been used for the purpose of allocating risk among Registrant, Cougar Merger Sub, Inc. and CGI Pharmaceuticals, Inc. rather than establishing matters as facts.

≠

The Agreement and Plan of Merger (the Arresto Merger Agreement) contains representations and warranties of Registrant, Arroyo Merger Sub, Inc. and Arresto Biosciences, Inc. made solely to each other as of specific dates. Those representations and warranties were made solely for purposes of the Arresto Merger Agreement and may be subject to important qualifications and limitations agreed to by Registrant, Arroyo Merger Sub, Inc. and Arresto Biosciences, Inc. Moreover, some of those representations and warranties may not be accurate or complete as of any specified date, may be subject to a standard of materiality provided for in the Arresto Merger Agreement and have been used for the purpose of allocating risk among Registrant, Arroyo Merger Sub, Inc. and Arresto Biosciences, Inc. rather than establishing matters as facts.

‡

The Agreement and Plan of Merger (the Calistoga Merger Agreement) contains representations and warranties of Registrant, Gilead Biopharmaceutics Ireland Corporation, Gilead Sciences Limited and Calistoga Pharmaceuticals, Inc. made solely to each other as of specific dates. Those representations and warranties were made solely for purposes of the Calistoga Merger Agreement and may be subject to important qualifications and limitations agreed to by Registrant, Gilead Biopharmaceutics Ireland Corporation, Gilead Sciences Limited and Calistoga Pharmaceuticals, Inc. Moreover, some of those representations and warranties may not be accurate or complete as of any specified date, may be subject to a standard of materiality provided for in the Calistoga Merger Agreement and have been used for the purpose of allocating risk among Registrant, Gilead Biopharmaceutics Ireland Corporation, Gilead Sciences Limited and Calistoga Pharmaceuticals, Inc. rather than establishing matters as facts.

†

The Agreement and Plan of Merger (the Pharmasset Merger Agreement) contains representations and warranties of Registrant, Merger Sub and Pharmasset, Inc. made solely to each other as of specific dates. Those representations and warranties were made solely for purposes of the Pharmasset Merger Agreement and may be subject to important qualifications and limitations agreed to by Registrant, Merger Sub and Pharmasset. Moreover, some of those representations and warranties may not be accurate or complete as of any specified date, may be subject to a standard of materiality provided for in the Pharmasset Merger Agreement and have been used for the purpose of allocating risk among Registrant, Merger Sub and Pharmasset rather than establishing matters as facts.

*	Management contract or compensatory plan or arrangement.

This certification accompanies the Form 10-K to which it relates, is not deemed filed with the Securities and Exchange Commission and is not to be incorporated by reference into any filing of Registrant under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended (whether made before or after the date of the Form 10-K), irrespective of any general incorporation language contained in such filing.

***	Furnished herewith.

Certain confidential portions of this Exhibit were omitted by means of marking such portions with an asterisk (the Mark). This Exhibit has been filed separately with the Secretary of the SEC without the Mark pursuant to Registrant’s Application Requesting Confidential Treatment under Rule 24b-2 under the Securities Exchange Act of 1934, as amended.

GILEAD SCIENCES, INC.

CONSOLIDATED FINANCIAL STATEMENTS

Years ended December 31, 2011, 2010, and 2009

CONTENTS


Report of Independent Registered Public Accounting Firm			95

Audited Consolidated Financial Statements:

Consolidated Balance Sheets			96

Consolidated Statements of Income			97

Consolidated Statements of Stockholders’ Equity			98

Consolidated Statements of Cash Flows			99

Notes to Consolidated Financial Statements			100

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors and Stockholders of Gilead Sciences, Inc.

We have audited the accompanying consolidated balance sheets of Gilead Sciences, Inc. as of December 31, 2011 and 2010, and the related consolidated statements of income, stockholders’ equity, and cash flows for each of the three years in the period ended December 31, 2011. Our audits also included the financial statement schedule listed in the Index at Item 15(a). These financial statements and schedule are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements and schedule based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the consolidated financial position of Gilead Sciences, Inc. at December 31, 2011 and 2010, and the consolidated results of its operations and its cash flows for each of the three years in the period ended December 31, 2011, in conformity with U.S. generally accepted accounting principles. Also, in our opinion, the related financial statement schedule, when considered in relation to the basic financial statements taken as a whole, presents fairly in all material respects the information set forth therein.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), Gilead Sciences, Inc.’s internal control over financial reporting as of December 31, 2011, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 23, 2012 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Redwood City, California

February 23, 2012

GILEAD SCIENCES, INC.

Consolidated Balance Sheets

(in thousands, except per share amounts)


	December 31,
	2011		2010
Assets
Current assets:
Cash and cash equivalents	$	9,883,777	$	907,879
Short-term marketable securities		16,491		1,190,789
Accounts receivable, net of allowances of $205,990 at December 31, 2011 and $150,942 at December 31, 2010		1,951,167		1,621,966
Inventories		1,389,983		1,203,809
Deferred tax assets		208,155		279,339
Prepaid taxes		246,444		320,424
Prepaid expenses		95,922		67,632
Other current assets		126,846		116,244

Total current assets		13,918,785		5,708,082
Property, plant and equipment, net		774,406		701,235
Noncurrent portion of prepaid royalties		174,584		203,790
Noncurrent deferred tax assets		144,015		153,379
Long-term marketable securities		63,704		3,219,403
Intangible assets		2,066,966		1,425,592
Other noncurrent assets		160,674		181,149

Total assets	$	17,303,134	$	11,592,630

Liabilities and Stockholders’ Equity
Current liabilities:
Accounts payable	$	1,206,052	$	803,025
Accrued government rebates		516,045		325,018
Accrued compensation and employee benefits		173,316		147,632
Income taxes payable		40,583		1,862
Other accrued liabilities		502,557		437,893
Deferred revenues		74,665		103,175
Current portion of convertible senior notes, net and other long-term obligations		1,572		646,345

Total current liabilities		2,514,790		2,464,950
Long-term deferred revenues		31,870		32,844
Long-term debt, net		7,605,734		2,838,573
Long-term income taxes payable		135,655		107,025
Other long-term obligations		147,736		27,401
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, par value $0.001 per share; 5,000 shares authorized; none outstanding		—		—
Common stock, par value $0.001 per share; 2,800,000 shares authorized; 753,106 and 801,998 shares issued and outstanding at December 31, 2011 and 2010, respectively		753		802
Additional paid-in capital		4,903,143		4,648,286
Accumulated other comprehensive income		58,200		30,911
Retained earnings		1,776,760		1,183,730

Total Gilead stockholders’ equity		6,738,856		5,863,729
Noncontrolling interest		128,493		258,108

Total stockholders’ equity		6,867,349		6,121,837

Total liabilities and stockholders’ equity	$	17,303,134	$	11,592,630

See accompanying notes.

GILEAD SCIENCES, INC.

Consolidated Statements of Income

(in thousands, except per share amounts)


	Year Ended December 31,
	2011		2010		2009
Revenues:
Product sales	$	8,102,359	$	7,389,921	$	6,469,311
Royalty revenues		268,827		545,970		491,818
Contract and other revenues		14,199		13,529		50,254

Total revenues		8,385,385		7,949,420		7,011,383

Costs and expenses:
Cost of goods sold		2,124,410		1,869,876		1,595,558
Research and development		1,229,151		1,072,930		939,918
Selling, general and administrative		1,241,983		1,044,392		946,686

Total costs and expenses		4,595,544		3,987,198		3,482,162