Edgar Filing: GILEAD SCIENCES INC

2013 Form 10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)



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

For the fiscal year ended December 31, 2013



o	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. ¨

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 28, 2013 was $60,272,481,253.*

The number of shares outstanding of the registrant's Common Stock on February 14, 2014 was 1,538,252,914.

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 2014 Annual Meeting of Stockholders, to be held on May 7, 2014, are incorporated by reference into Part III of this Report.

* Based on a closing price of $51.27 per share on June 28, 2013. Excludes 343,332,813 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 28, 2013. 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.

2013 Form 10-K Annual Report

Table of Contents



PART I
Item 1	Business	3
Item 1A	Risk Factors	31
Item 1B	Unresolved Staff Comments	47
Item 2	Properties	47
Item 3	Legal Proceedings	47
Item 4	Mine Safety Disclosures	52

PART II
Item 5	Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	53
Item 6	Selected Financial Data	55
Item 7	Management's Discussion and Analysis of Financial Condition and Results of Operations	56
Item 7A	Quantitative and Qualitative Disclosures about Market Risk	72
Item 8	Financial Statements and Supplementary Data	75
Item 9	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure	75
Item 9A	Controls and Procedures	75
Item 9B	Other Information	77

PART III
Item 10	Directors, Executive Officers and Corporate Governance	77
Item 11	Executive Compensation	77
Item 12	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	77
Item 13	Certain Relationships and Related Transactions, and Director Independence	77
Item 14	Principal Accountant Fees and Services	77

PART IV
Item 15	Exhibits and Financial Statement Schedules	78

SIGNATURES		140

We own or have rights to various trademarks, copyrights and trade names used in our business, including the following: GILEAD^®, GILEAD SCIENCES^®, STRIBILD^®, COMPLERA^®, EVIPLERA^®, TRUVADA^®, VIREAD^®, EMTRIVA^®, TYBOST^®, SOVALDI^®, HEPSERA^®, VITEKTA^®,LETAIRIS^®, RANEXA^®, CAYSTON^®, AMBISOME^®, VISTIDE^®, VOLIBRIS^®, 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 31. 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 strive to transform and simplify care for people with life-threatening illnesses around the world. Gilead's primary areas of focus include human immunodeficiency virus (HIV), liver diseases such as chronic hepatitis B virus (HBV) infection and chronic hepatitis C virus (HCV) infection, oncology/inflammation and serious cardiovascular and respiratory conditions. Headquartered in Foster City, California, we have operations in North and South America, Europe and Asia-Pacific. We continue 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.

2013 Highlights

Over the past year, we executed on our strategy to bring best-in-class drugs to market. In the liver diseases area, we received approval from the U.S. Food and Drug Administration (FDA) of our new drug application (NDA) for Sovaldi^® (sofosbuvir 400 mg). Sovaldi is a once-daily oral nucleotide analog polymerase inhibitor for the treatment of HCV infection as a component of a combination antiviral treatment regimen. The approval of Sovaldi represents a significant improvement in the treatment paradigm for some patients with HCV as it has shortened the duration of treatment and reduced or completely eliminated the need for pegylated interferon (peg-IFN) injections in certain viral genotype populations. In the HIV area, we expanded our single tablet regimen product offerings for the treatment of HIV with the European launch of Stribild^® (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg), which combines four of our medicines in a once-daily single tablet regimen. We also received approval of Tybost^® (cobicistat) and Vitekta^®(elvitegravir 85 mg and 150 mg), each a component of Stribild, from the European Commission. In the oncology/inflammation area, we filed for FDA and European Medicines Agency (EMA) marketing approval of idelalisib (formerly GS-1101), an investigational, targeted, oral inhibitor of PI3K delta, for the treatment of patients with refractory indolent non-Hodgkin’s lymphoma (iNHL) and relapsed chronic lymphocytic leukemia (CLL). We also continued to advanced our research and development pipeline, with more than 200 active clinical studies at the end of 2013, of which over 60 are Phase 3 clinical trials.

HIV Program

A substantial portion of our revenues is derived from our eight marketed HIV products. In 2013, we continued to be at the forefront of advancing HIV treatment through the development of new single tablet regimens. Our long-term goal is to ensure that all HIV patients have the option to choose a single tablet regimen that is right for them. Single tablet regimens allow patients to adhere to a fully suppressive course of therapy more easily and consistently, which is critical for the successful management of the disease. Because of this, we continue to focus on the development of new HIV medicines and co-formulations. With the launch of Stribild in the United States in 2012 and in Europe in 2013, Complera^®/Eviplera^® (emtricitabine 200 mg/rilpivirine 25 mg/tenofovir disoproxil fumarate 300 mg) in 2011 and Atripla^® (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) in 2006, we now have three single tablet regimens available. In December 2013, we received FDA and EMA approval for Complera/Eviplera to be used by certain adult patients switching from another stable antiretroviral regimen. Complera/Eviplera was first approved in 2011 in the United States and Europe for patients new to antiretroviral therapy.

In September 2013, we received EMA approval for Tybost, a pharmacokinetic enhancer that boosts blood levels of certain HIV medicines. Tybost is indicated as a boosting agent for the HIV protease inhibitors atazanavir (300 mg once daily) and darunavir (800 mg once daily) as part of antiretroviral combination therapy in adults with HIV-1 infection. This approval allows for the marketing of Tybost in all 28 countries of the European Union. In November 2013, the EMA approved Vitekta, an integrase inhibitor for the treatment of HIV-1 infection in adults without known mutations associated with resistance to elvitegravir, the active ingredient of Vitekta. Vitekta is indicated for use as part of HIV treatment regimens that include a ritonavir-boosted protease inhibitor.

We also made important progress with the clinical development of tenofovir alafenamide (TAF), formerly known as GS-7340. A Phase 2 study showed that TAF is efficacious at a fraction of a dose of Viread^®(tenofovir disoproxil fumarate 300 mg) and provides potential safety advantages. Based on these results, we commenced a Phase 3 trial evaluating the single tablet regimen of TAF, elvitegravir, cobicistat and emtricitabine for the treatment of HIV infection in treatment-naïve adults. Under an agreement with Janssen R&D Ireland (Janssen), formerly Tibotec Pharmaceuticals, we are also conducting Phase 2 trials evaluating a single tablet regimen of TAF, cobicistat, darunavir and emtricitabine for the treatment of HIV infection. In the first quarter of 2013, we completed enrollment of two Phase 3 clinical trials comparing a TAF-based regimen to Stribild in patients new to HIV treatment. Data from the studies will be available in the first quarter of 2014.

Liver Diseases

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 current standard of care, which involves up to 48 weeks of therapy with a peg-IFN/ribavirin (RBV)-containing regimen. 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 are significant.

Through the acquisition of Pharmasset, Inc. (Pharmasset) in 2012, we acquired sofosbuvir, a nucleotide analog that acts to inhibit the replication of HCV. In December 2013, we received FDA approval for sofosbuvir under the brand name Sovaldi for the treatment of HCV as a component of a combination antiviral treatment regimen. In January 2014, we received European Commission approval of Sovaldi for the treatment of HCV. Sovaldi’s efficacy has been established in patients with HCV genotypes 1, 2, 3 or 4 infection (in United States and Europe) and genotypes 5 and 6 infection (in Europe), including those with hepatocellular carcinoma meeting Milan criteria (awaiting liver transplantation) and those with HCV/HIV-1 co-infection. U.S. recommended regimens and treatment duration for Sovaldi combination therapy in HCV mono-infected or HCV/HIV-1 co-infected patients are as follows:



	Treatment	Duration
Genotype 1 or 4	Sovaldi + peg-IFN + RBV	12 weeks
Genotype 2	Sovaldi + RBV	12 weeks
Genotype 3	Sovaldi + RBV	12 weeks
Hepatocellular carcinoma awaiting liver transplantation	Sovaldi + RBV	48 weeks or until liver transplant

As noted in the table above, compared to the current standard of care of up to 48 weeks, Sovaldi has shortened the duration of treatment to as little as 12 weeks and reduced or completely eliminated the need for peg-IFN injections in certain viral genotype populations.

As our second generation therapy for the treatment of HCV, we are advancing the fixed-dose combination of ledipasvir/sofosbuvir (LDV/SOF) for the treatment of genotype 1 patients. Our NDA for the fixed-dose combination of LDV/SOF was supported by three clinical trials and was filed in February 2014. The first study, named ION-1, evaluates the fixed-dose combination of LDV/SOF with and without RBV for either 12 or 24 weeks in treatment-naïve genotype 1 HCV-infected patients. The second Phase 3 study, named ION-2, evaluates the fixed-dose combination with RBV for 12 weeks or without RBV for 24 weeks of therapy among treatment-experienced genotype 1 HCV-infected patients. The third study, named ION-3, evaluates the fixed-dose combination of LDV/SOF with and without RBV for eight weeks or without RBV for 12 weeks in non-cirrhotic, treatment-naïve genotype 1 HCV-infected patients.

In Japan, we fully enrolled a Phase 3 study evaluating sofosbuvir in genotype 2 HCV-infected patients. We expect to file for regulatory approval of sofosbuvir in Japan in mid-2014. We also completed enrollment of Phase 3 studies evaluating the fixed-dose combination of LDV/SOF in genotype 1 infected HCV patients and sofosbuvir and RBV in genotype 2 infected HCV patients. Based on the results of these Phase 3 studies, we plan to file for regulatory approval for the fixed-dose combination of LDV/SOF in Japan in the fourth quarter of 2014.

Our long term goal is to develop an oral pan-genotypic oral therapy for all HCV patients across genotypes. The fixed-dose combination of sofosbuvir and GS-5816, a nucleotide NS5B inhibitor/pan-genotypic NS5A inhibitor, is currently in Phase 2 clinical trials.

Oncology/Inflammation

Over the last five years we have worked to advance our oncology franchise. Idelalisib, a PI3K delta inhibitor antibody, formerly known as GS-1101, is being evaluated for the treatment of iNHL and CLL. In September 2013, we filed an NDA for idelalisib for the treatment of patients with iNHL that is refractory (non-responsive) to rituximab and to alkylating-agent-containing chemotherapy. The FDA has set a target review date under the Prescription Drug User Fee Act (PDUFA) of September 11, 2014. In December 2013, we also filed an NDA for idelalisib for relapsed CLL. In February 2014, the FDA, which previously granted Breakthrough Therapy designation for idelalisib in CLL, accepted our NDA and set a target review date of August 6, 2014 under the PDUFA. In November 2013, our marketing authorization application for idelalisib for iNHL and CLL was validated by the EMA. With the acquisition of YM Biosciences Inc. in 2013, we acquired momelotinib or GS-0387, formerly known as CYT387, a JAK inhibitor being evaluated for the treatment of myelofibrosis. In 2013, we also advanced momelotinib to Phase 3 trials.

Our Products

HIV


•	Stribild is an oral formulation dosed once a day for the treatment of HIV-1 infection in treatment-naive adults. Stribild is our third complete single regimen for the treatment of HIV and is a fixed-dose combination of our antiretroviral medications, Vitekta, Tybost, Viread and Emtriva^® (emtricitabine). Stribild was approved by the FDA in August 2012 and the EMA in May 2013.

•

Complera/Eviplera is an oral formulation dosed once a day for the treatment of HIV-1 infection in 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 Janssen's non-nucleoside reverse transcriptase inhibitor, Edurant (rilpivirine).

•

Atripla 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 and Emtriva and Bristol Myers-Squibb Company's (BMS) non-nucleoside reverse transcriptase inhibitor, Sustiva (efavirenz).

•

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. In 2012, the FDA also approved Truvada, in combination with safer sex practices, to reduce the risk of sexually acquired HIV-1 infection in adults at high risk, a strategy called pre-exposure prophylaxis (PrEP).

•

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 two years of age and older. In 2012, the European Commission also approved the use of Viread in combination with other antiretroviral agents for the treatment of HIV-1 infected pediatric patients aged two to less than 18 years with nucleoside reverse transcriptase inhibitor resistance or toxicities precluding the use of first line pediatric agents. Viread is also approved for the treatment of chronic HBV in adults.


•	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.


•	Tybost is a pharmacokinetic enhancer dosed once a day that boosts blood levels of certain HIV medicines. Tybost is indicated as a boosting agent for the HIV protease inhibitors atazanavir and darunavir as part of antiretroviral combination therapy in adults with HIV-1 infection. We received marketing approval of Tybost in all 28 countries of the European Union.

•

Vitekta is an oral formulation of an integrase inhibitor, dosed once a day as part of combination therapy to treat HIV infection in adults without known mutations associated with resistance to elvitegravir, the active ingredient of Vitekta. Vitekta is indicated for use as part of HIV treatment regimens that include a ritonavir-boosted protease inhibitor. We received marketing approval of Vitekta in all 28 countries of the European Union.

Liver Diseases

•

Sovaldi is an oral formulation of a nucleotide analog polymerase inhibitor dosed once a day for the treatment of HCV as a component of a combination antiviral treatment regimen. Sovaldi was approved by the FDA in December 2013 and by the European Commission in January 2014. Sovaldi’s efficacy has been established in patients with HCV genotypes 1, 2, 3 or 4 infection (in United States and Europe) and genotypes 5 and 6 infection

(in Europe), including those with hepatocellular carcinoma meeting Milan criteria (awaiting liver transplantation) and those with HCV/HIV-1 co-infection.

•

Viread is an oral formulation of a nucleotide analog reverse transcriptase inhibitor, dosed once a day for the treatment of chronic HBV in adults with compensated and decompensated liver disease. We licensed to GlaxoSmithKline Inc. (GSK) the rights to commercialize Viread for the treatment of chronic HBV in China, Japan and Saudi Arabia. In 2012, the EMA approved the use of Viread for the treatment of chronic HBV infection in adolescent patients aged 12 to less than 18 years with compensated liver disease and evidence of immune active disease. Viread is also approved for the treatment of HIV infection in patients two years of age and older in combination with other antiretroviral agents.


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

Cardiovascular

•

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.


•	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.

•

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 (Astellas) 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 U.S. 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


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

•

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


•	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.


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

•

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 Valeant Pharmaceuticals, Inc. (Valeant), which acquired Eyetech in 2012. Valeant 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 Valeant and Pfizer based on worldwide sales of Macugen.

Sales of our antiviral products, which include products in our HIV and liver diseases areas described above, were $9.34 billion in 2013, $8.14 billion in 2012 and $7.05 billion in 2011. This represented 83% of our total revenues in 2013 and 84%

of our total revenues in both 2012 and 2011. Sales of our other products were $1.46 billion in 2013, $1.26 billion in 2012 and $1.05 million in 2011. This represented 13% of our total revenues in 2013, 2012 and 2011. See Item 7, Management's Discussion and Analysis included in this Annual Report on Form 10-K for more information regarding our revenues.

Commercialization and Distribution

We have U.S. and international commercial sales operations, with marketing subsidiaries in Australia, Austria, Belgium, Brazil, Canada, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hong Kong, Ireland, Italy, Japan, the Netherlands, New Zealand, Norway, Poland, Portugal, Russia, South Korea, Spain, Sweden, Singapore, 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 Stribild, Complera, Atripla, Truvada, Viread, Hepsera, Emtriva, Ranexa, Sovaldi 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, 2013, 2012 and 2011. On a combined basis, in 2013, these wholesalers accounted for approximately 80% of our product sales in the United States and approximately 50% 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 Stribild, Eviplera, Atripla, Truvada, Sovaldi, Viread, Hepsera, Emtriva, Vitekta, Tybost and AmBisome in Europe and countries outside the United States, where the product is approved, either through our commercial teams, third-party distributors or corporate partners.

U.S. Patient Access

We make it a priority to increase access to our medicines for people who can benefit from them, regardless of their ability to pay. In the United States, our U.S. patient assistance programs help make our therapies accessible for uninsured individuals and those who need financial assistance. We also support programs for those unable to afford the co-payments associated with health insurance programs. Half of all patients taking our HIV medicines in the United States already receive them through federal and state programs at substantially discounted prices. We have a long history of working with state AIDS Drug Assistance Programs (ADAPs) to provide lower pricing for our HIV medicines. The price freeze we instituted for ADAPs in 2008 was extended in 2013 through the end of 2014, providing important support to these critical programs as they evolve in the changing United States healthcare environment.

Access in the Developing World

Through the Gilead Access Program, established in 2003, certain of our products for the treatment of HIV, chronic HBV and visceral leishmaniasis are available at substantially reduced prices in the developing world. Gilead delivers its medicines in these countries by working with regional business partners to distribute brand-name Viread and Truvada at prices that are based on a country's ability to pay and represent little or no profit to Gilead. We also have partnerships with India-based companies to expand access to generic versions of our HIV medications in the least-developed countries of the world (see below).

We work closely with the World Health Organization and with non-governmental organizations to provide AmBisome for the treatment of leishmaniasis 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 is being used to treat more than 50,000 patients in resource-limited countries.

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 HIV prevention strategy called PrEP. With FDA approval for PrEP in 2012, Truvada became the first agent indicated for uninfected individuals to reduce the risk of acquiring HIV through sex.

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

•

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.

•

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.

•

Licenses with Generic Manufacturers. We have entered into non-exclusive license agreements with Indian generic manufacturers, granting them 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 and quality 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 cobicistat and elvitegravir, including generic versions of our combination product containing the four active ingredients of cobicistat, elvitegravir, tenofovir disoproxil fumarate and emtricitabine. 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 HBV in the same countries where they are authorized to sell generic versions of tenofovir disoproxil fumarate for HIV. In August 2012, we announced new collaborations with Indian partners to produce and distribute generic emtricitabine in the developing world, including single tablet regimens containing emtricitabine and fixed-dose combinations of emtricitabine co-formulated with other Gilead HIV medicines.

•

Merck & Co., Inc. (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. In 2008, we also entered into an agreement with Merck to commercialize Atripla in over 30 low-middle income countries, including Brazil, Egypt and Mexico.

•

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.

•

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 granted 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 generic versions of the single tablet regimen consisting of elvitegravir, cobicistat, tenofovir disoproxil fumarate and emtricitabine and to our product candidates, elvitegravir and cobicistat, to those same generic pharmaceutical manufacturers in India for distribution in the developing world.


•	Janssen. In 2011, we expanded our agreement with Janssen 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 marketed 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:


•	efficacy;


•	safety;


•	tolerability;


•	acceptance by doctors;


•	ease of patient compliance;


•	patent protection;


•	ease of use;


•	price;


•	insurance and other reimbursement coverage;


•	distribution; and


•	marketing.

Our HIV Products

The HIV landscape is becoming more competitive and complex as treatment trends continue to evolve. A growing number of 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 37 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 Healthcare (ViiV), established by GSK and Pfizer and focused on HIV therapies. These products compete with Stribild, Complera/Eviplera, Atripla and Truvada. For Tybost, we compete with ritonavir, marketed by AbbVie Inc. (AbbVie). Our HIV products also compete broadly with HIV products from AbbVie, Boehringer Ingelheim GmbH, Merck, Roche and Janssen. In addition, Tivicay (dolutegravir), an integrase inhibitor, launched in the fourth quarter of 2013 by ViiV, could adversely impact sales of our HIV products.

We also face competition from generic HIV products. BMS's Videx EC (didanosine, ddI) became the first generic HIV product in the United States in 2004. GSK's Retrovir (zidovudine) faces competition in the United States as a result of the launch of generic zidovudine in 2005. BMS's Zerit (stavudine) faces competition in the United States as a result of the launch of generic stavudine in 2008. Epivir (lamivudine), marketed by ViiV, is competitive with emtricitabine, the active pharmaceutical ingredient of Emtriva and a component of Atripla, Truvada, Complera/Eviplera and Stribild. 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, Portugal and 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, which resulted in an increase in the rebate for Viread in Turkey. Generic efavirenz, the active pharmaceutical

ingredient in Sustiva and a component of our Atripla, is now available in Canada and Europe and we expect competition from generic efavirenz in the United States in 2015. This may put pricing pressure on our HIV products.

Our Liver Diseases Products

Our HCV product, Sovaldi, competes with Janssen's Olysio (simeprevir) in the United States and to a lesser extent with direct-acting antivirals, Victrelis (boceprevir), marketed by Merck and Incivek (telaprevir) marketed by Vertex Pharmaceuticals Incorporated.

Our HBV products, Viread and Hepsera, face significant competition from existing and expected therapies for treating patients with HBV, 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 Europe in 2011, 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 plc and is sold in major countries throughout North and South America, Europe and Asia.

Viread and Hepsera for the treatment of HBV also compete with established immunomodulatory therapies, including Intron-A (interferon alfa-2b), which is sold by Merck 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 HBV.

Our Cardiovascular Products

Letairis competes directly with Tracleer (bosentan) and Opsumit (macitentan). Both drugs are sold by Actelion Pharmaceuticals US, Inc.. Letairis also competes with Adcirca (tadalafil) 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, which 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.

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, a bacterial infection.

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 approved in Japan and South Korea.

Our Other Products

AmBisome faces strong competition from several current and expected competitors. 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 three lipid formulations that claim similarity to AmBisome becoming available outside of the United States, including the possible entry of such formulations in Taiwan. 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 generic fomivirsen.

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. For more information regarding certain of these relationships, including their ongoing financial and accounting impact on our business, see Item 8, Note 9 Collaborative Arrangements in 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 for 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.

•

BMS. In 2004, we entered into a collaboration arrangement with BMS to develop and commercialize the single tablet regimen of our Truvada and BMS's Sustiva (efavirenz) 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 that operates as a limited liability company named Bristol-Myers Squibb & Gilead Sciences, LLC, which we consolidate. 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. In 2006, we and BMS amended the joint venture's collaboration agreement to allow the joint venture to sell Atripla in Canada.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 efavirenz and Truvada. Since the net selling price for Truvada may change over time relative to the net selling price of efavirenz, both our and BMS's respective economic interests in the joint venture may vary annually. Starting in 2011, except for a limited number of activities that are jointly managed, the parties no longer coordinate detailing and promotional activities in the United States, and the parties have reduced their joint promotional efforts since we launched Complera in August 2011 and Stribild in August 2012. 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 terminating party then has the right to continue to sell Atripla and become the continuing party, but will be obligated to pay the terminated party certain royalties for a three-year period following the effective date of the termination.

In 2007, Gilead Sciences Limited, a wholly-owned subsidiary in Ireland, and BMS entered into a collaboration agreement under which we and BMS commercialize and distribute Atripla in the European Union, Iceland, Liechtenstein, Norway and Switzerland (collectively, the European Territory). The parties formed a limited liability company which we consolidate, to manufacture Atripla for distribution in the European Territory using

efavirenz that it purchases from BMS at BMS's estimated net selling price of efavirenz in the European Territory. Starting in 2012, except for a limited number of activities that are jointly managed, the parties no longer coordinate detailing and promotional activities in the region. As of December 31, 2013 and 2012, efavirenz purchased from BMS at BMS's estimated net selling price of efavirenz in the European Territory is included in inventories on our Consolidated Balance Sheets. 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 Territory. In addition, either party may terminate the agreement for any reason and such termination will be effective two calendar quarters after notice of termination. The non-terminating party has the right to continue to sell Atripla and become the continuing party, 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 continuing 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.

•

Janssen. In 2009, we entered into a collaboration agreement with Janssen to develop and commercialize a fixed-dose combination of our Truvada and Janssen'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, Janssen 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 drug products.

We recorded €71.5 million (approximately $100.0 million) in reimbursable research and development (R&D) expenses incurred by Janssen in the development of rilpivirine through December 31, 2011. This was 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. Janssen has exercised a right to co-detail the combination product in some of the countries where Gilead is the selling party.

In 2011 and 2013, we amended the collaboration agreement to include distribution of Complera/Eviplera to the rest of the world. We have the right to distribute the product in North America, Europe, Latin America (except Mexico), Australia and New Zealand, while Janssen has the right to distribute the product in the other regions, including Japan and Russia.

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 Janssen for Complera/Eviplera is approximately the market price of rilpivirine, less a specified percentage of up to 30% in major markets.

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. Janssen 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.

•

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 elvitegravir for the treatment of HIV infection. We 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, 2013, we have made total milestone payments of $60.0 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 Collaborations

We also have a number of collaborations with partners for the R&D of certain compounds and drug candidates. None of our research collaborations rose to a level that is significant to us from a financial statement perspective and where significant ongoing collaboration activity exists.

Research and Development

Our R&D philosophy and strategy is to develop best-in-class drugs that improve safety or efficacy for unmet medical needs. We intend to continue committing significant resources to R&D opportunities and business development activity.

Our product development efforts cover a wide range of medical conditions, including HIV/AIDS and liver diseases such as HBV and HCV, inflammation/oncology and serious cardiovascular and respiratory conditions. We have research scientists in Foster City, Fremont, San Dimas and Oceanside, California; Branford, Connecticut; Seattle, Washington; and Alberta, Canada engaged in the discovery and development of new molecules and technologies that we hope will lead to the approval of new medicines addressing unmet needs.

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
Cobicistat		Cobicistat is a pharmacokinetic enhancer dosed once a day that boosts blood levels of certain HIV medicines. It was approved as a component of Stribild. In September 2013, the European Commission approved cobicistat, marketed as Tybost, as a stand- alone boosting agent for the HIV protease inhibitors atazanavir and darunavir as part of antiretroviral combination therapy in adults with HIV-1 infection.
Elvitegravir		Elvitegravir is an oral integrase inhibitor dosed once a day as part of combination therapy to treat HIV infection in adults. It was approved as a component of Stribild. In November 2013, the European Commission approved elvitegravir, marketed as Vitekta for the treatment of HIV infection in adults without known mutations associated with resistance to elvitegravir. Vitekta is indicated for use as part of HIV treatment regimens that include a ritonavir-boosted protease inhibitor.
Product in Phase 3
Single tablet regimen of TAF, elvitegravir, cobicistat and emtricitabine		A single tablet regimen of TAF, an NRTI, elvitegravir, cobicistat and emtricitabine is being evaluated for the treatment of HIV infection in treatment-naïve adults.
Product in Phase 2
Single tablet regimen of TAF, darunavir, cobicistat and emtricitabine		Under an agreement with Janssen, a single tablet regimen of TAF, darunavir, cobicistat and emtricitabine is being evaluated for the treatment of HIV infection.

Product Candidates for the Treatment of Liver Diseases



Product Candidates		Description
Marketing Application Pending
Fixed-dose combination of LDV/SOF		A fixed-dose combination of ledipasvir, an oral NS5A inhibitor, and sofosbuvir taken with and without RBV is under evaluation in Phase 3 trials for the treatment of HCV.
Products in Phase 3
TAF		TAF is an NRTI under evaluation for the treatment of HBV.
Products in Phase 2
Fixed-dose combination of sofosbuvir and GS-5816		A fixed-dose combination of sofosbuvir and GS-5816, a nucleotide NS5B inhibitor/pan-genotypic NS5A inhibitor, being evaluated for the treatment of HCV.
GS-4774		GS-4774 is a Tarmogen T cell immunity stimulator under evaluation for the treatment of HBV.
GS-9451		GS-9451 is an oral NS3 protease inhibitor being evaluated for the treatment of HCV.
GS-9669		GS-9669 is a non-nucleoside NS5B site 2 polymerase inhibitor under evaluation for the treatment of HCV.
Simtuzumab (GS-6624)		Simtuzumab is a monoclonal antibody being evaluated for the treatment of liver fibrosis, nonalcoholic steatohepatitis and primary sclerosing cholangitis.
Products in Phase 1
GS-5745		GS-5745 is a MMP9 mAb inhibitor being evaluated for the treatment of ulcerative colitis.
GS-9620		GS-9620 is an oral TLR-7 agonist being evaluated for the treatment of HBV and HCV.

Product Candidates for the Treatment of Oncology/Inflammation



Product Candidates		Description
Marketing Application Pending
Idelalisib		Idelalisib is a PI3K delta inhibitor antibody for the treatment of iNHL and CLL. In September 2013, we submitted an NDA to the FDA for approval of idelalisib for the treatment of iNHL. The FDA has set a target review date under the PDUFA of September 11, 2014. In December 2013, we submitted an NDA to the FDA for approval of idelalisib for the treatment of CLL. The PDUFA date for the filing is August 6, 2014. Our marketing authorization application for idelalisib for iNHL and CLL was validated by the EMA in November 2013.
Products in Phase 3
Momelotinib (GS-0387/CYT387)		Momelotinib or GS-0387, formerly known as CYT387, is a JAK inhibitor being evaluated for the treatment of myelofibrosis.
Products in Phase 2
GS-9820		GS-9820 is a PI3K delta inhibitor being evaluated for the potential treatment of lymphoid malignancies.
GS-9973		GS-9973 is a spleen tyrosine kinase (Syk) inhibitor being evaluated with hematological malignancies.
Simtuzumab		Simtuzumab is a monoclonal antibody being evaluated for the treatment of myelofibrosis, colorectal and pancreatic cancer.
Products in Phase 1
GS-5745		GS-5745 is a MMP9 maB inhibitor being evaluated for the treatment of solid tumors.

Product Candidates for the Treatment of Cardiovascular Diseases



Product Candidates		Description
Product in Phase 3
Ranolazine		Ranolazine is a late sodium current inhibitor approved for the treatment of chronic angina, which is being evaluated for the treatment of incomplete revascularization post-percutaneous coronary intervention and the treatment of type II diabetes.
Product in Phase 2
Ranolazine		Ranolazine is also being evaluated for the treatment of paroxysmal atrial fibrillation.
Product in Phase 1
GS-4997		GS-4977 is an ASK-1 inhibitor being evaluated for the treatment of diabetic nephropathy.
GS-6615		GS-6615 is a late sodium current inhibitor being evaluated for the treatment of LQT-3 Syndrome, hypertrophic cardiomyopathy and ventricular tachycardia/ventricular fibrillation.

Product Candidates for the Treatment of Respiratory Diseases



Product Candidates		Description
Product in Phase 2
GS-5806		GS-5806 is an inhalable small molecule antiviral fusion inhibitor being evaluated for the treatment of respiratory syncytial virus.
Simtuzumab		Simtuzumab is a monoclonal antibody being evaluated for the treatment of idiopathic pulmonary fibrosis.

In total, our R&D expenses for 2013 were $2.12 billion compared with $1.76 billion for 2012 and $1.23 billion for 2011. In addition to our internal discovery and clinical development programs, we seek to add to our portfolio of products through product acquisitions, licenses and collaborations. The following table shows some of our recent acquisitions:



Year	Company	Therapeutic area
2011	Arresto Biosciences, Inc.	Fibrotic diseases and cancer
2011	Calistoga Pharmaceuticals, Inc.	Cancer and inflammatory diseases
2012	Pharmasset, Inc.	Chronic HCV
2013	YM Biosciences Inc.	Hematological and immune cell disorders and inflammatory diseases and cancers

Our largest transaction was the acquisition of Pharmasset in 2012 for $11.05 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. We received FDA and EMA approval of Sovaldi (sofosbuvir) and we filed an NDA for the fixed-dose combination of LDV/SOF for the treatment of HCV-infected patients in February 2014.

Patents and Proprietary Rights

U.S. and European Patent Expiration

The following table shows the estimated expiration dates (including Patent Term Extension, Supplementary Protection Certificates and/or Pediatric exclusivity where granted) in the United States and Europe for the primary (typically compound) patents for our Phase 3 product candidates. 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. For our product candidates that are single tablet regimens, the estimated patent expiration date provided corresponds to the latest expiring compound patent for one of the active ingredients in the single tablet regimen.



Phase 3 Product Candidates	Patent Expiration
Product Candidates for the Treatment of HIV	U.S.	E.U.
Single tablet regimen of TAF, elvitegravir, cobicistat and emtricitabine	2029	(2027)
Single tablet regimen of TAF and emtricitabine	2022	(2021)

Product Candidate for the Treatment of Liver Diseases
Single tablet regimen of LDV/SOF for the treatment of HCV	2030	(2030)
Single agent TAF for the treatment of HBV	2022	(2021)

Product Candidate for the Treatment of Oncology/Inflammation
Idelalisib for the treatment of CLL and iNHL	2025	(2025)
Momelotinib for the treatment of myelofibrosis	2030	(2028)
Product Candidate for the Treatment of Cardiovascular Diseases
Ranolazine for the treatment of incomplete revascularization post-percutaneous coronary intervention and the treatment of type II diabetes	2019	2019

Dates in parentheses reflect the estimated expiration date of patents which may issue from currently pending applications. The estimated expiration dates do not include any potential additional exclusivity (e.g., patent term extension, supplementary protection certificates or pediatric exclusivity) that is not yet granted.

The following table shows the actual or estimated expiration dates (including Patent Term Extension, Supplementary Protection Certificates and/or Pediatric exclusivity where granted) in the United States and Europe for the primary (typically compound) patents for our marketed products. 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. For our product that are single tablet regimens (e.g., Truvada, Atripla, Complera/Eviplera and Stribild), the estimated patent expiration dates provided correspond to the latest expiring compound patent for one of the active ingredients in the single tablet regimen.



Products	Patent Expiration
	U.S.	E.U.
Vistide	2010	2012
Hepsera	2014	2016
AmBisome	2016	2008
Macugen	2017	2017
Tamiflu	2017	2016
Letairis	2018	2020
Viread	2018*	2018
Ranexa	2019**	2023
Atripla	2021	2018
Cayston	2021	2021
Emtriva	2021	2016
Truvada	2021	2018
Lexiscan	2022	2025
Complera/Eviplera	2023	2022
Vitekta	***	2023
Sovaldi	2029	(2028)
Stribild	2029	(2027)
Tybost	***	(2027)

Dates in parentheses reflect the estimated expiration date of patents which may issue from currently pending applications. The estimated expiration dates do not include any potential additional exclusivity (e.g., patent term extension, supplementary protection certificates or pediatric exclusivity) that is not yet granted.

In 2013, Gilead and Teva Pharmaceuticals (Teva) reached an agreement in principle to settle the ongoing patent litigation concerning the four patents that protect tenofovir disoproxil fumarate in our Viread, Truvada and Atripla products. Under the agreement, Teva will be allowed to launch a generic version of Viread on December 15, 2017. The settlement agreement was filed with the Federal Trade Commission and Department of Justice as required by law.


**	In 2013, Gilead and Lupin Limited (Lupin) reached an agreement to settle the patent litigation prior to issuance of the court’s decision. Under the agreement, Lupin would be allowed to launch a generic version of Ranexa on February 27, 2019. The settlement agreement was filed with the Federal Trade Commission and Department of Justice as required by law.

*** This product is not yet approved in the U.S.

Patent Protection and Certain Challenges

Patents and other proprietary rights are very important to our business. 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 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 certain of the active pharmaceutical ingredients of Stribild, Complera/Eviplera, Atripla, Truvada, Emtriva, Hepsera, Letairis, Vistide and Vitekta are held by third parties. We acquired exclusive rights to these patents in the agreements we have with these parties. 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 HBV, 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 or supplementary protection certificates in some countries. For example, extensions for the patents or supplementary protection certificates 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 in some countries.

It is also very important that we do not infringe the valid patents of third parties. If we infringe the valid patents of third parties, 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 Letairis Education and Access Program (LEAP), our restricted distribution program designed to support Letairis.

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 or first to file an application directed toward 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/derivation proceedings or litigation to determine the right to a patent. Litigation and interference/derivation proceedings are unpredictable and expensive, such that, even if we are ultimately successful, our results of operations may be adversely affected by 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 other proceedings regarding the enforcement or validity of our existing patents or any future patents could result in the invalidation of our patents or substantially reduce their protection. From time to time, certain individuals or entities may challenge our patents.

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.

Litigation Regarding Sofosbuvir

In January 2012, we acquired Pharmasset. Through the acquisition, we acquired sofosbuvir (formerly known as GS-7977), a nucleotide analog that acts to inhibit the replication of HCV. In December 2013, we received FDA approval of sofosbuvir, brand-named Sovaldi. We have received a number of contractual and intellectual property claims regarding sofosbuvir. We have carefully considered these claims both prior to and following the acquisition and believe they are without merit.

We own patents that claim sofosbuvir as a chemical entity and its metabolites. However, the existence of patents does not necessarily guarantee our right to practice the patented technology or commercialize the patented product. Third parties may have, or obtain rights to, patents that allegedly could be used to prevent or attempt to prevent us from commercializing sofosbuvir. For example, we are aware of patents and patent applications owned by other parties that may be alleged by such parties to cover the use of sofosbuvir. If these parties successfully obtain valid and enforceable patents, and successfully prove infringement of those patents by sofosbuvir, we could be prevented from selling sofosbuvir unless we were able to obtain a license under such patents. Such a license may not be available on commercially reasonable terms or at all. Further, if any party is successful in establishing exclusive rights to sofosbuvir, our expected revenues and earnings from the sale of sofosbuvir would be adversely affected.

Contract Arbitration with Jeremy Clark

outcome of an arbitration proceeding required by Mr. Clark's employment agreement. Instead of proceeding with arbitration, Mr. Clark filed two additional lawsuits in September 2009 and June 2010, both of which the court subsequently dismissed. In September 2010, Mr. Clark filed a motion seeking reconsideration of the court's December 2008 order which the court denied. In December 2011, Mr. Clark filed a motion to appoint a special prosecutor. In February 2012, the court issued an order requiring Mr. Clark to enter arbitration or risk dismissal of his case. Mr. Clark filed a demand for arbitration in March 2012. The arbitration panel held a hearing in April 2013. In June 2013, the arbitration panel issued its decision in favor of Pharmasset (now Gilead) and Dr. Schinazi. In August 2013, Gilead and Dr. Schinazi filed a motion in the U.S. District Court for the Northern District of Alabama seeking to have the court confirm the arbitration decision and Mr. Clark filed a motion seeking to vacate the arbitration decision. The court has not yet ruled on these motions.

Arbitration with F. Hoffman-La Roche Ltd and Hoffman-La Roche Inc. (collectively, Roche)

Gilead (as successor to Pharmasset) is a party to an October 29, 2004 collaboration agreement with Roche. The agreement granted Roche rights to develop PSI-6130, a cytidine analog, and its prodrugs, for the treatment of HCV infection. The collaborative research efforts under the agreement ended on December 31, 2006. Roche later asked Pharmasset to consider whether Roche may have contributed to the inventorship of sofosbuvir 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. In March 2013, Roche initiated an arbitration against us and Pharmasset, predecessor to Gilead Pharmasset LLC, regarding the collaboration agreement. In the arbitration demand, Roche asserts that it has an exclusive license to sofosbuvir pursuant to the collaboration agreement because sofosbuvir, a prodrug of a uridine monophosphate analog, is allegedly a prodrug of PSI-6130, a cytidine analog. Roche further claims that, because it has exclusive rights to sofosbuvir, it also has an exclusive license to a patent covering sofosbuvir, and that we will infringe that patent by selling and offering for sale products containing sofosbuvir. Gilead and Gilead Pharmasset LLC filed their response to Roche's arbitration demand in April 2013.

Interference Proceedings and Litigation with Idenix Pharmaceuticals, Inc.

In February 2012, we received notice that the U.S. Patent and Trademark Office (USPTO) had declared Interference No. 105,871 (First Idenix Interference) between our U.S. Patent No. 7,429,572 patent and Idenix Pharmaceuticals, Inc.'s (Idenix) pending U.S. Patent Application No. 12/131,868. An interference is an administrative proceeding before the USPTO designed to determine who was the first to invent the subject matter claimed by both parties. Our patent covers metabolites of sofosbuvir and RG7128, a prodrug of a cytidine nucleoside analog that Pharmasset licensed to Roche. Idenix is attempting to patent a class of compounds, including these metabolites. The purpose of the First Idenix Interference was to determine who was first to invent these compounds and therefore who is entitled to the patent claiming these compounds. In March 2013, the USPTO Patent Trials and Appeal Board (the Board) determined that Idenix is not entitled to the benefit of any of its early application filing dates because none of those patent applications, including the application that led to Idenix’s U.S. Patent No. 7,608,600 patent (the ‘600 patent), taught how to make the compounds in dispute. The Board also determined that because we are entitled to the filing date of our earliest application, we were first to file the patent application on the compounds in dispute, and we were therefore the “senior party” in the First Idenix Interference. On January 29, 2014, the Board determined that Pharmasset and not Idenix was the first to invent the compounds in dispute and accordingly Gilead prevailed. In its decision, the Board held that Idenix failed to prove that it was first to conceive of any of the compounds in dispute. Specifically, Idenix failed to prove that the Idenix inventors had identified the structure, a method of making and a use for any of the disputed compounds. The Board went on to conclude that Idenix failed to work diligently toward making and testing the compounds in dispute during the relevant time period. Idenix has appealed the Board’s decisions to the U.S. District Court for the District of Delaware. If either or both of the Board’s decisions are reversed on appeal and the court determines that Idenix is entitled to their patent claims, and it is determined that we have infringed those claims, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir and RG7128 in the United States. A decision by the District Court can be appealed by either party to the U.S. Court of Appeals for the Federal Circuit (CAFC).We believe that the claims in the Idenix application involved in the First Idenix Interference, and similar U.S. and foreign patents claiming the same compounds and metabolites, are invalid. As a result, we filed an Impeachment Action in the Federal Court of Canada to invalidate Idenix Canadian Patent No. 2,490,191, which is the Canadian patent that corresponds to the ’600 patent and the Idenix patent application that is the subject of the First Idenix Interference. Idenix has now asserted that our Canadian Patent No. 2,527,657, corresponding to our U.S. Patent No. 7,429,572 patent in the First Idenix Interference, is invalid. We filed a similar legal action in Norway in the Oslo District Court seeking to invalidate Idenix's corresponding Norwegian patent. In September 2013, Idenix filed an invalidation action in the Norwegian proceedings against our Norwegian Patent No. 333700 patent, which corresponds to our U.S. Patent No. 7,429,572 patent. The trial was held in November 2013. The court has not yet issued a decision. In August 2013, Idenix also filed a request for invalidation with the Chinese Patent Office of our Chinese Patent CN ZL200480019148.4, which corresponds to our U.S. Patent No. 7,429,572 patent. We filed a legal action in the Federal Court of Australia seeking to invalidate Idenix’s Australian p

atent corresponding to the ‘600 patent. In April 2013, Idenix asserted that the commercialization of sofosbuvir will infringe the Australian patent corresponding to the ‘600 patent. We may bring similar action in other countries in the future. Idenix has not been awarded patents on these compounds from the European Patent Office, Japan or China. In the event such patents issue, we expect to challenge them in proceedings similar to those we invoked in Canada, Norway and Australia. If the courts hearing these proceedings determine that Idenix is entitled to their patent claims and it is determined that we have infringed those claims, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir and RG7128 in that country.

In December 2013, after receiving Gilead’s request to do so, the USPTO declared Interference No. 105,981 (Second Idenix Interference) between our pending U.S. Patent Application No. 11/854,218 and the ‘600 patent. The ‘600 patent includes claims directed to methods of treating HCV with nucleoside compounds similar to those which were involved in the First Idenix Interference. The Second Idenix Interference will determine who was first to invent the claimed methods of treating HCV. In the declaration of the Second Idenix Interference, the USPTO has initially designated Gilead as the junior party based upon the patent application filing dates appearing on the face of the ‘600 patent. On February 5, 2014, the USPTO issued an Order to Show Cause against Idenix in the Second Idenix Interference. The Order requires Idenix to explain why judgment should not be entered against it in the Second Idenix Interference in favor of Gilead based upon the outcome of the First Idenix Interference. The Order indicates that the claims in the ‘600 patent which are involved in the Second Idenix Interference are unpatentable due to Gilead prevailing in the First Idenix Interference and that Idenix will not be allowed to claim the benefit of the filing date of its earlier filed patent applications. We believe the Board’s determination in the First Idenix Interference that Idenix is not entitled the benefit of any of its earlier application filing dates, including the filing date of the ‘600 patent, will be equally applicable to the Second Idenix Interference. If we are correct, the Board may conclude that Gilead is the senior party in the Second Idenix Interference, consistent with the determination in the First Idenix Interference. In light of the Board’s conclusion in the First Idenix Interference that the application that led to the ‘600 patent does not teach how to make the claimed compounds, it is possible that the Board will make the same determination in the Second Idenix Interference and eliminate the need for the Board to address who was the first to invent the claimed methods of treating HCV. However, if the Board does consider who was the first to invent the claimed methods of treating HCV and ultimately concludes that Gilead was first, the claims in the '600 patent may be revoked. If the Board determines that Idenix was first to invent and is entitled to these patent claims, and it is determined in other proceedings that we have infringed those claims, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir and RG7128. Any determination by the Board can be appealed by either party to U.S. federal court. In December 2013, Idenix, Universita Degli Studi di Cagliari (UDSG), Centre National de la Recherche Scientifique and L’Université Montpellier II sued us in U.S. District Court for the District of Delaware alleging that the commercialization of sofosbuvir will infringe the ‘600 patent and that an interference exists between the ‘600 patent and our U.S. Patent No. 8,415,322 patent. We believe that the claims in the ‘600 patent are invalid and that we have the sole right to commercialize sofosbuvir. However, if the court disagrees with our view and further determines that the ‘600 patent is infringed, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir. A decision by the District Court can be appealed by either party to the CAFC.

Also in December 2013, Idenix and UDSG sued us in U.S. District Court for the District of Massachusetts alleging that the commercialization of sofosbuvir will infringe U.S. Patent Nos. 6,914,054 and 7,608,597 patents. We believe that Idenix’s patents are invalid and would not be infringed by our commercialization of sofosbuvir and that we have the sole right to commercialize sofosbuvir. However, if the court disagrees with our view and determines that these patents are infringed, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir. A decision by the District Court can be appealed by either party to the CAFC.

We have an expansive patent portfolio covering NS5A inhibitors for the treatment of HCV. Following the recent disclosure of the structure of Idenix’s NS5A inhibitor, samatasvir (also known as IDX-719), we are evaluating the compound in light of the pending claims of our U.S. Patent Application No. 13/491,446.

Litigation with Merck & Co., Inc.

In August 2013, Merck & Co., Inc. (Merck) contacted us requesting that we pay royalties on the sales of sofosbuvir and take a license to U.S. Patent No. 7,105,499 patent and U.S. Patent No. 8,481,712 patent, which it co-owns with Isis Pharmaceuticals, Inc. We believe that Merck’s patents are invalid and would not be infringed by our commercialization of sofosbuvir and that we have the sole right to commercialize sofosbuvir. Accordingly, in August 2013, we filed a lawsuit in the U.S. District Court for the Northern District of California seeking declaratory judgment that the Merck patents are invalid and not infringed. Merck’s U.S. Patent Nos. 7,105,499 and 8,481,712 patents cover compounds which do not include, but may relate to, sofosbuvir. During patent prosecution, Merck amended its patent application in an attempt to cover compounds related to sofosbuvir and ultimately extract royalty payments for sofosbuvir’s commercialization, or to exclude it from the market. If the court determines that Merck’s patents are valid and that we have infringed those claims, we may be required to

obtain a license from and pay royalties to Merck to commercialize sofosbuvir. Either party can appeal a decision by the District Court to the CAFC.

Litigation with AbbVie, Inc. (AbbVie)

AbbVie recently obtained U.S. Patent Nos. 8,466,159 and 8,492,386 patents, which purport to claim the use of a combination of LDV/SOF for the treatment of HCV. We own published and pending patent applications directed to the use of combinations for the treatment of HCV, and, specifically, to combinations of ledipasvir and sofosbuvir. Certain of those applications were filed before AbbVie's recently issued patents. For this reason and others, we believe AbbVie's patents are invalid.

Accordingly, in December 2013, we filed a lawsuit in the U.S. District Court for the District of Delaware seeking declaratory judgment that the AbbVie patents are invalid and unenforceable, as well as other relief. We believe that Abbott Laboratories, Inc. and AbbVie conspired to eliminate competition in the HCV market by falsely representing to the PTO that they, and not Gilead, invented methods of treating HCV using a combination of LDV/SOF. In February 2014, AbbVie responded to our lawsuit by filing a lawsuit also in the U.S. District Court for the District of Delaware alleging that our LDV/SOF product will infringe their patents. We do not expect AbbVie's patents to block or delay the commercialization of our combination products. If the court determines that AbbVie’s patents are valid and that we have infringed those claims, we may be required to obtain a license from and pay royalties to AbbVie to commercialize sofosbuvir combination products. Either party can appeal a decision by the District Court to the CAFC.

Litigation with Generic Manufacturers

As part of the approval process for some of our products, the FDA granted a New Chemical Entity (NCE) exclusivity period during which other manufacturers' applications for approval of generic versions of our product will not be approved. Generic manufacturers may challenge the patents protecting products that have been granted NCE exclusivity one year prior to the end of the NCE exclusivity period. Generic manufacturers have sought and may continue to seek FDA approval for a similar or identical drugs through an abbreviated new drug application (ANDA), the application form typically used by manufacturers seeking approval of a generic drug.

Tenofovir Disoproxil Fumarate, Emtricitabine and Fixed-dose Combination of Emtricitabine, Tenofovir Disoproxil Fumarate and Efavirenz

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, 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 fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate. In December 2008, we filed a lawsuit in U.S. District Court for the Southern District of 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 fixed-dose combination of emtricitabine, tenofovir disoproxil fumarate and efavirenz. In the notice, Teva challenged the same two emtricitabine patents. In May 2009, we filed another lawsuit in U.S. District Court for the Southern District of 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 generic versions of our Atripla and Truvada products. In the notice related to Teva's ANDA for a generic version of 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 Teva's ANDA for a generic version of Truvada, Teva challenged four patents related to tenofovir disoproxil fumarate and two additional patents related to emtricitabine. In March 2010, we filed lawsuits against Teva for infringement of the four Viread patents and two additional emtricitabine patents. In March 2010, Bristol-Myers Squibb Company and Merck filed a lawsuit against Teva for infringement of the patents related to efavirenz. Because we filed our lawsuits within the requisite 45-day period provided in the Hatch Waxman Act, there were stays preventing FDA approval of Teva's ANDAs for 30 months or until a district court decision adverse to the patents. The 30-month stay for all three Teva ANDAs expired in July 2012. In April 2013, we and Teva reached an agreement to settle the ongoing patent litigation concerning the four patents that protect tenofovir disoproxil fumarate in Atripla, Truvada and Viread. Under the agreement, Teva will be allowed to launch a generic version of Viread on December 15, 2017. The settlement agreement was filed with the Federal Trade Commission and Department of Justice as required by law. On October 1, 2013, the court’s dismissal of the case pursuant to the settlement agreement between the parties became final. A trial in the lawsuit against Teva related to the U.S. patents protecting emtricitabine in Atripla and Truvada was held in October 2013. In February 2014, we and Teva reached an agreement in principle to settle the ongoing patent litigation concerning the emtricitabine patents that protect Atripla and Truvada. The

terms of the settlement agreement are confidential. The settlement agreement will be filed with the Federal Trade Commission and Department of Justice as required by law.

In November 2011, we received notice that Teva submitted an abbreviated new drug submission (ANDS) to the Canadian Minister of Health requesting permission to manufacture and market a generic fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate. 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 in the Federal Court of Canada seeking an order of prohibition against approval of this ANDS.

In December 2011, we received notice that Teva submitted an ANDS to the Canadian Minister of Health requesting permission to manufacture and market a generic fixed-dose combination of emtricitabine, tenofovir disoproxil fumarate and efavirenz. 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 fixed-dose combination of emtricitabine, tenofovir disoproxil fumarate and efavirenz. In February 2012, we filed a lawsuit against Teva in the Federal Court of Canada seeking an order of prohibition against approval of this ANDS. In August 2012, we received notice that Teva submitted an ANDS to the Canadian Minister of Health requesting permission to manufacture and market a generic version of Viread. In the notice, Teva alleges that two patents associated with tenofovir disoproxil fumarate are invalid, unenforceable and/or will not be infringed by Teva's manufacture, use or sale of a generic version of Viread, Truvada, and Atripla. In September 2012, we filed a lawsuit against Teva in the Federal Court of Canada seeking an order of prohibition against approval of this ANDS. Also in August 2012, Teva filed an Impeachment Action in the Federal Court of Canada seeking invalidation of our two Canadian patents associated with Viread. We are currently defending that Impeachment Action. The requests for orders of prohibition in connection with all three of Teva’s ANDS filings (for Teva’s generic versions of Viread, Truvada and Atripla) were consolidated and a hearing on the consolidated requests for the orders of prohibition took place in September 2013. In December 2013, the court issued our requested order prohibiting the Canadian Minister of Health from issuing a Notice of Compliance for Teva’s generic versions of our Viread, Truvada and Atripla products until expiry of our patent in July 2017. Teva has appealed this decision and this decision does not ultimately resolve the validity challenges raised by Teva in the Impeachment Action. If Teva is successful in invalidating our patents, Teva may be able to launch generic versions of our Viread, Truvada and Atripla products prior to the expiry of our patents. A trial in the Impeachment Action is scheduled for January 2015.

In July 2012, we received notice that Lupin Limited (Lupin) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Truvada. In the notice, Lupin alleges that four patents associated with emtricitabine and four patents associated with tenofovir disoproxil fumarate are invalid, unenforceable and/or will not be infringed by Lupin's manufacture, use or sale of a generic version of a fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate. In August 2012, we filed a lawsuit against Lupin in U.S. District Court for the Southern District of New York for infringement of our patents. We anticipate a trial in this case in the fourth quarter of 2014. Either party can appeal a decision by the District Court to the CAFC. If Lupin is successful in invalidating our patents, Lupin may be able to launch generic version of our Truvada product prior to the expiry of our patents.

In July 2012, we received notice that Cipla Ltd. (Cipla) submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Emtriva and a generic version of Viread. In the notice, Cipla alleges that two patents associated with emtricitabine are invalid, unenforceable and/or will not be infringed by Cipla's manufacture, use or sale of a generic version of emtricitabine and four patents associated with tenofovir disoproxil fumarate are invalid, unenforceable and/or will not be infringed by Cipla's manufacture, use or sale of a generic version of tenofovir disoproxil fumarate. In August 2012, we filed lawsuits against Cipla in U.S. District Court for the Southern District of New York for infringement of our patents. We anticipate a trial in this case in the fourth quarter of 2014. Either party can appeal a decision by the District Court to the CAFC. If Cipla is successful in invalidating our patents, Cipla may be able to launch generic versions of our Viread and/or Emtriva products prior to the expiry of our patents.

In October 2012, we received notice that Lupin submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of Viread. In the notice, Lupin alleges that four patents associated tenofovir disoproxil fumarate are invalid, unenforceable and/or will not be infringed by Lupin's manufacture, use or sale of a generic version of tenofovir disoproxil fumarate. In October 2012, we filed a lawsuit against Lupin in U.S. District Court for the Southern District of New York for infringement of our patents. We anticipate a trial in this case in the fourth quarter of 2014. Either party can appeal a decision by the District Court to the CAFC. If Lupin is successful in invalidating our patents, Lupin may be able to launch generic version of our Viread product prior to the expiry of our patents.

Ranolazine

In June 2010, we received notice that Lupin submitted an ANDA to the FDA requesting permission to manufacture and market a generic version of sustained release ranolazine. In the notice, Lupin alleged 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 in U.S. District Court for the District of New Jersey for infringement of our patents for Ranexa. The trial took place in April and May 2013. In August 2013, the parties reached agreement to settle the patent litigation prior to issuance of the court’s decision. Under the agreement, Lupin would be allowed to launch a generic version of Ranexa on February 27, 2019. The settlement agreement was filed with the Federal Trade Commission and Department of Justice as required by law.

Tamiflu

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 oseltamivir phosphate 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 in U.S. District Court for the District of New Jersey for infringement of one of the patents associated with Tamiflu. In December 2012, the court issued a ruling in favor of Gilead and Roche, that our patent is not invalid for the reasons stated in Natco's notice letter. Natco has appealed this decision to the CAFC. A hearing on Natco’s appeal took place in January 2014. The court has not yet issued a decision in this appeal. If Natco is successful in the appeal, the case will be remanded to the U.S. District Court for the District of New Jersey for a full trial on the merits.

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 claims in the patents may be narrowed or invalidated and the patent protection for Atripla, Truvada, Viread, Emtriva and Tamiflu in the United States and Atripla, Truvada and Viread in Canada could be substantially shortened. Further, if all of the patents covering one or more products are invalidated, the FDA or Canadian Minister of Health could approve the requests to manufacture a generic version of such products in the United States or Canada, respectively, prior to the expiration date of those patents. The sale of generic versions of these products earlier than their patent expiration would have a significant negative effect on our revenues and results of operations.

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 and Oceanside, California; Edmonton, Alberta, Canada and Cork, Ireland, 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 Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Hepsera, Emtriva, Tybost, Vitekta, Sovaldi, Ranexa, AmBisome, Cayston and Vistide. We generally use multiple third-party contract manufacturers to manufacture the active pharmaceutical ingredients in our products. We are the exclusive manufacturer of ambrisentan, the active pharmaceutical ingredient of Letairis, although another supplier is qualified to make the active pharmaceutical ingredient in Letairis.

We also rely on third-party contract manufacturers to manufacture our tablet or capsule products. For example, we use multiple third-party contract manufacturers to tablet Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Tybost, Vitekta, Sovaldi, Letairis, Hepsera and Ranexa. Emtriva encapsulation is also completed by third-party contract manufacturers.

We also have manufacturing agreements with many of our corporate partners. Roche, by itself and through third parties, is responsible for manufacturing Tamiflu. Under our agreement with Roche, through a joint manufacturing committee composed of representatives from Roche and Gilead, 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.

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, California manufacturing facility, we manufacture, package and label solid dosage oral form products. We also fill and package solid dosage form products, including Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Emtriva, Sovaldi and Ranexa, in their finished forms and label Hepsera at our facilities in San Dimas. We manufacture Cayston and AmBisome at our San Dimas facility. We depend on a single supplier for the active pharmaceutical ingredient in Cayston and for the high quality cholesterol and the active pharmaceutical ingredient used in the manufacture of AmBisome. Because we are the exclusive supplier of AmBisome, 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 to meet market needs.

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 fill and package drug product for Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Tybost, Tiveka and Sovaldi and label Hepsera and Emtriva at our facilities in Cork, Ireland. We also perform quality control testing, final labeling and secondary packaging of both Cayston and 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, Alberta facility in Canada, 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, California facility 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 simtuzumab, an investigational monoclonal antibody candidate in development for treatment of certain cancers and for fibrotic diseases, and another antibody which is currently in Phase 2 clinical trials.

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. For example, in 2012, due to unexpected delays both in qualifying two new external sites and with expanding Cayston manufacturing in San Dimas, we were unable to supply enough Cayston to fulfill our projected demand. During February through September 2012, we suspended access for patients with new prescriptions for Cayston, subject to certain exceptions where specific medical need exists. As a result of our inability to manufacture sufficient Cayston to meet demand, the amount of revenues we received from the sale of Cayston was reduced.

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 EMA. Similar regulations are in effect in other countries.

Our manufacturing operations are subject to routine inspections by regulatory agencies. For example, in April 2013, the FDA conducted an inspection of our Foster City facility and issued Form 483 Inspectional Observations, which noted deficiencies in documentation and validation of certain quality testing procedures and methods. As a result of the observations, the FDA delivered Complete Response Letters notifying us that it was unable to approve our NDAs for elvitegravir and cobicistat as standalone agents. In mid-October 2013, the FDA completed its sofosbuvir pre-approval inspection of our Foster City facility. Following that inspection, the FDA issued additional Form 483 Inspectional Observations citing deficiencies related to testing and reconciliation of stability samples, testing protocols, testing of shipping samples, and procedures for calibrating test equipment. We recently completed and filed our responses to these observations with the FDA. If we are unable to remedy the deficiencies cited by the FDA in these inspections, our currently marketed products and the timing of regulatory approval of products in development could be adversely affected. Further, there is risk that regulatory agencies in other countries where marketing applications are pending will undertake similar additional reviews or apply a heightened standard of review, which could delay the regulatory approvals for products in those countries. If approval of any of our product candidates, including idelalisib and the fixed-dose combination of LDV/SOF, were delayed or if production of our marketed products was interrupted, our anticipated revenues and our stock price would be adversely affected.

Access to Supplies and Materials

We need access to certain supplies and products 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. For example, a significant portion of the raw materials and intermediates used to manufacture our HIV and liver disease products (Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Emtriva, Tybost, Vitekta and Sovaldi) 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 2013 and included 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 IND, 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:


•	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.


•	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.

•

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 an 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 Oceanside and 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, Complera and Sovaldi 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. The European Union also has requirements for approval of manufacturing facilities for all products that are approved for sale by the European regulatory authorities.

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 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. Effective March 1, 2013, an automatic reduction in federal spending or “sequestration” is in effect. Under sequestration, across-the-board cuts have been implemented which could reduce the amount of federal and state funds to support ADAPs. 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. In prior quarters, because of the insufficiency of federal and state funds and as many states reduced eligibility criteria, we saw an increase in the number of patients on state ADAP wait lists, and we may see similar increases in future periods as a result of any reduction in federal and state ADAP support resulting from the sequestration. 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.

with certain 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, tenders 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 and froze the price of prescription pharmaceuticals. As generic drugs come to market, we may face price decreases for our products in some countries in the European Union. Further, cost containment pressures in the European Union, especially in Southern Europe, could lead to delays in the treatment of patients and also delay pricing approval, which could negatively impact the commercialization of new products.

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

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 ADAPs. As a result of the 2010 legislation, the discounts, rebates and fees that impacted us include:


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


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


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

We, along with other pharmaceutical manufacturers of branded drug products, were required to pay a portion of a new industry fee (also known as the pharmaceutical excise tax) of $2.8 billion for 2013, calculated based on select government sales during the 2011 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 from $2.8 billion in 2013 to $3.0 billion in 2014, 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 of other companies, we expect our portion of the pharmaceutical excise tax to increase as well. We estimate our portion of the pharmaceutical excise tax to be approximately $150 - $170 million in 2014, compared to approximately $110 million in 2013 and approximately $85 million in 2012. The pharmaceutical 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 generally prohibit anyone from knowingly presenting, or causing to be presented, a false or fraudulent claim for payment by federal and certain state payers (including Medicare and Medicaid), or knowingly making, using or causing to be made or used, a false record or statement material to a false or fraudulent claim. Our sales, marketing and medical 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 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. 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 local custom. 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). Violations can also lead to the imposition of a Corporate Integrity Agreement or similar government oversight program. 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 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.

Employees

As of January 31, 2014, we had approximately 6,100 full-time employees. We believe we have good relations with our employees.

Environment, Health and Safety

We have evaluated our current level of environmental impact and have identified ways to reduce our energy consumption. Some factors that contribute to our environmental impact include greenhouse gas emissions produced by employee commutes, the energy and water consumed by our facilities, and the use of hazardous materials such as chemicals, viruses and radioactive compounds in our R&D facilities. Pursuant to our evaluation, we have taken some initial measures to

address these impacts. For example, we have established employee commuter programs, evaluated the energy efficiency of our buildings, and installed low-flow water fixtures. We have also implemented proactive programs to minimize the occurrence of hazardous materials incidents and to reduce the risk of accidental environmental contamination and worker injury.

We are subject to a number of laws and regulations that require compliance with federal, state, and local regulations regarding workplace safety and protection of the environment. We anticipate additional regulations in the near future. Laws and regulations are implemented and under consideration to mitigate the effects of climate change mainly caused by greenhouse gas emissions. Our business is not energy intensive. Therefore, we do not anticipate being subject to a cap and trade system or other mitigation measure that would materially impact our capital expenditures, operations, or competitive position. Based on current information, and subject to the finalization of proposed regulations, we believe that our primary risk related to climate change is increased energy costs. 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. Misuse or accidents involving hazardous materials could lead to significant litigation, fines, and penalties.

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.

Transactions with Iran

We did not have any transactions with Iran during 2013 that would require disclosure in this Form 10-K.


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.

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

We currently depend on sales of our products for the treatment of human immunodeficiency virus (HIV) infection, particularly Atripla, Truvada, Stribild and Complera/Eviplera to support our existing operations. Most of 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, 2013, Atripla, Truvada, Stribild and Complera/Eviplera product sales together were $8.13 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 Stribild, Complera/Eviplera, Atripla, Truvada and Tybost, for any number of reasons including, but not limited to, the following:

•

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.


•	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.


•	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.

•

As generic HIV products are introduced into major markets, our ability to maintain pricing and market share may be affected. For example, generic versions of Sustiva (efavirenz), a component of our Atripla, are now available in Canada and Europe and we expect competition from generic efavirenz in the United States in 2015. This may increase pricing pressure on our HIV products. Tivicay (dolutegravir), an integrase inhibitor, launched in the fourth quarter by ViiV Healthcare (ViiV) could impact sales of our HIV products.

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 April 2013, we announced our decision to terminate our Phase 3 clinical trial of aztreonam for inhalation solution for the treatment of bronchiectasis.

In February 2014, we filed a new drug application (NDA) with the U.S. Food and Drug Administration (FDA) for approval of the fixed-dose combination of ledipasvir/sofosbuvir (LDV/SOF) for genotype 1 patients, who represent a majority of patients infected with chronic hepatitis C virus (HCV) infection in the United States and Europe. If approved, LDV/SOF will likely only require genotype 1 HCV patients to take one pill, once per day for eight or 12 weeks without ribavirin (RBV) or pegylated interferon (peg-IFN) peg-IFN. We expect to file for approval of LDV/SOF in Europe in the first quarter of 2014. We have also filed marketing applications for idelalisib for the treatment of patients with indolent non-Hodgkin’s lymphoma (iNHL) and chronic lymphocytic leukemia (CLL).

These marking applications may not be approved by the FDA, European Medicines Agency (EMA) or other foreign regulatory authorities on a timely basis, or at all. Even if marketing approval is granted for these products, there may be significant limitations on their use. Further, we may be unable to file our marketing applications for new products.

Our inability to accurately estimate demand for our products, the uptake of new products or the timing of fluctuations in the inventories maintained by customers makes it difficult for us to accurately forecast sales and may cause our revenues and earnings to fluctuate, which could adversely affect our financial results and our stock price.

We are unable to accurately estimate demand for our products, including uptake from new products as demand is dependent on a number of factors. For example, our HCV products, Sovaldi and LDV/SOF, if approved, represent a significant change in the treatment paradigm for HCV- infected patients due to the shortened duration of treatment and the reduction or elimination of the need for peg-IFN injection and RBV. Because these products are in a new therapeutic area for us and patient demand is dependent on a number of factors, revenues from these products in 2014 and beyond are difficult for us and investors to estimate. Since Sovaldi was recently approved and it is not clear when, or if, LDV/SOF will ultimately be approved, demand for these products will depend in part on the amount of their coverage under private and public insurance programs in the United States and our ability to obtain and maintain government reimbursement in countries outside the United States. In addition, doctors may choose to wait to treat their genotype 1 HCV- infected patients until later in 2014 or 2015 when they anticipate the approval and availability of LDV/SOF and another competitor’s all-oral regimen for the treatment of genotype 1 HCV-infected patients. Also, because our HCV products represent a significant change in the treatment paradigm of HCV infection and are highly anticipated by the medical and patient community, sales levels or prescription growth rates early in the launch may not be indicative of future results. Because HCV-related revenues are difficult to predict, investors may have widely varying expectations that may be materially higher or lower than our actual revenues. To the extent Sovaldi revenues exceed or fall short of these expectations, our stock price may experience significant volatility.

In 2013, approximately 80% 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-wholesaler 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 2013, strong wholesaler and sub-wholesaler purchases may result in inventory draw-down by wholesalers and sub-wholesalers in the first quarter of 2014. 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 AIDS Drug Assistance Programs (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. Federal and state budget pressures, including sequestration, as well as the annual grant cycles for federal and state ADAP funds, may cause ADAP purchasing patterns to not reflect patient demand. For example, in the first quarters of certain prior years, we observed large non-retail purchases by a number of state ADAPs that exceeded patient demand. We believe such purchases were driven by the grant cycle for federal ADAP funds. 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 government agencies and other purchasers to reduce inventory of our products in the distribution channels, which has decreased our revenues and caused fluctuations in our product sales and earnings. We may continue to see this trend in the future.

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


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


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


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


•	we, along with other pharmaceutical manufacturers of branded drug products, were required to pay a portion of a new industry fee (also known as the pharmaceutical excise tax) of $2.8 billion for 2013, calculated based on select government sales during the 2011 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 from $2.8 billion in 2013 to $3.0 billion in 2014, 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 of other companies, we expect our portion of the pharmaceutical excise tax to increase as well. We estimate our portion of the pharmaceutical excise tax to be approximately $150 - $170 million in 2014 compared to approximately $110 million in 2013 and approximately $85 million in 2012. The pharmaceutical 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.

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

In countries outside the United States, 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 countries patients are unlikely to use prescription drugs that are not reimbursed by their governments. In addition, negotiating prices with certain 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, tenders and profit control, and they expect prices of prescription pharmaceuticals to decline over the life of the product or as volumes increase.

Approximately 40% 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.

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 a joint venture established by GlaxoSmithKline Inc.(GSK) and Pfizer Inc. (Pfizer), ViiV Healthcare (ViiV), which markets fixed-dose combination products that compete with Stribild, Complera/Eviplera, Atripla and Truvada. For example, lamivudine, marketed by this joint venture, is competitive with emtricitabine, the active pharmaceutical ingredient of Emtriva and a component of Complera/Eviplera, Atripla and Truvada. For Tybost, we compete with ritonavir marketed by AbbVie Inc. (AbbVie). In addition, Tivicay (dolutegravir), an integrase inhibitor, launched in the fourth quarter of 2013 by ViiV, could adversely impact sales of our HIV products.

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, Portugal and 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, which resulted in an increase in the rebate for Viread in Turkey. Generic versions of Sustiva (efavirenz), a component of our Atripla, are now available in Canada and Europe and we expect competition from generic efavirenz to be in the United States in 2015. This may increase pricing pressure on our HIV products.

Our HCV product, Sovaldi competes with Janssen R&D Ireland Olysio (simeprevir) in the United States and to a lesser extent with direct-acting antivirals, Victrelis (boceprevir) marketed by Merck & Co., Inc. (Merck) and Incivek (telaprevir) marketed by Vertex Pharmaceuticals Incorporated.

For Viread and Hepsera for treatment of chronic hepatitis B virus (HBV) infection, 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 and Pfizer. In addition, we are aware of at least three lipid formulations that claim similarity to AmBisome becoming available outside of the United States, including the possible entry of such formulations and Taiwan. 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 products 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 any of these competitors gain market share on our products, it could adversely affect our results of operations and stock price.

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 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.

Regulatory authorities have been moving towards more active and transparent pharmacovigilance and are making greater amounts of stand-alone safety information directly available to the public through websites and other means, e.g. periodic safety update report summaries, risk management plan summaries and various adverse event data. Safety information, without the appropriate context and expertise, may be misinterpreted and lead to misperception or legal action which may potentially cause our product sales or stock price to decline.

Further, 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 EMA and comparable regulatory agencies in other countries. We are continuing clinical trials for Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Emtriva, Tybost, Vitekta, Sovaldi, Hepsera, Letairis, Ranexa, AmBisome 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.

For example, under FDA rules, we are often required to conduct post-approval clinical studies to assess a known serious risk, signals of serious risk or to identify an unexpected serious risk and implement a Risk Evaluation and Mitigation Strategy for our products, 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 April 2013, we announced our decision to terminate our Phase 3 clinical trial of aztreonam for inhalation solution for the treatment of bronchiectasis. 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 ranolazine for the treatment of incomplete revascularization post-percutaneous coronary intervention and type II diabetes and our single tablet regimen of tenofovir alafenamide/elvitegravir/cobicistat/emtricitabine, 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.

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, including on the clinical trials that will be necessary to advance our other product candidates, may cause our operating results to fluctuate from quarter to quarter and volatility in our stock price.

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:


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


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


•	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;


•	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;


•	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;


•	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


•	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.

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 HBV 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 HBV 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 HBV. Consequently, GSK's marketing strategy for Hepsera and Viread for the treatment of chronic HBV 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 HBV 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 HBV 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:


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


•	not effectively sell or support Cayston or Letairis;


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


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


•	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.

Our success will depend to a significant degree on our ability to defend 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:


•	obtain patents and licenses to patent rights;


•	preserve trade secrets;


•	defend against infringement and efforts to invalidate our patents; and


•	operate without infringing on the intellectual property 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 or first to file an application directed toward 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 litigation, interference or other proceedings to determine the right to a patent. Litigation, interference or other proceedings are unpredictable and expensive, such that, even if we are ultimately successful, our results of operations may be adversely affected by such events.

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 HBV, the indication for which Hepsera has been developed.

Generic manufacturers have sought, and may continue to seek, FDA approval to market generic versions of our products through an abbreviated new drug application (ANDA), the application form typically used by manufacturers seeking approval of a generic drug. See a description of our ANDA litigation in "Legal Proceedings" beginning on page 47 and risk factor entitled "Litigation with generic manufacturers has reduced and may continue to reduce our earnings. If we are unsuccessful in all or some of these lawsuits, some or all of our claims in the patents may be narrowed or invalidated and generic versions of our products could be launched prior to our patent expiry." beginning on page 43.

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 valid patents of third parties, 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 patents that may relate to our operation of LEAP, our restricted distribution program designed to support Letairis and we are aware of patents and patent applications owned by other parties that may claim to cover the use of sofosbuvir. See a description of our litigation regarding sofosbuvir in the risk factor entitled "If any party is successful in establishing exclusive rights to sofosbuvir, our expected revenues and earnings from the sale of sofosbuvir could be adversely affected" beginning on page 39.

Furthermore, 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. If our trade secrets or confidential information become known or independently discovered by competitors or if we enter into disputes over ownership of inventions, our business and results of operations could be adversely affected.

If any party is successful in establishing exclusive rights to sofosbuvir, our expected revenues and earnings from the sale of sofosbuvir could be adversely affected.

Contract Arbitration with Jeremy Clark

In December 2011, Mr. Clark filed a motion to appoint a special prosecutor. In February 2012, the court issued an order requiring Mr. Clark to enter arbitration or risk dismissal of his case. Mr. Clark filed a demand for arbitration in March 2012. The arbitration panel held a hearing in April 2013. In June 2013, the arbitration panel issued its decision in favor of Pharmasset (now Gilead) and Dr. Schinazi. In August 2013, Gilead and Dr. Schinazi filed a motion in the U.S. District Court for the Northern District of Alabama seeking to have the court confirm the arbitration decision and Mr. Clark filed a motion seeking to vacate the arbitration decision. The court has not yet ruled on these motions.

Arbitration with F. Hoffman-La Roche Ltd and Hoffman-La Roche Inc. (collectively, Roche)

Interference Proceedings and Litigation with Idenix Pharmaceuticals, Inc.

milar to those we invoked in Canada, Norway and Australia. If the courts hearing these proceedings determine that Idenix is entitled to their patent claims and it is determined that we have infringed those claims, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir and RG7128 in that country.

In December 2013, Idenix, Universita Degli Studi di Cagliari (UDSG), Centre National de la Recherche Scientifique and L’Université Montpellier II sued us in U.S. District Court for the District of Delaware alleging that the commercialization of sofosbuvir will infringe the ‘600 patent and that an interference exists between the ‘600 patent and our U.S. Patent No. 8,415,322 patent. We believe that the claims in the ‘600 patent are invalid and that we have the sole right to commercialize sofosbuvir. However, if the court disagrees with our view and further determines that the ‘600 patent is infringed, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir. A decision by the District Court can be appealed by either party to the CAFC.

Litigation with Merck & Co., Inc.

Litigation with AbbVie, Inc. (AbbVie)

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 EMA. 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, in 2012, due to unexpected delays both in qualifying two new external sites and with expanding Cayston manufacturing in San Dimas, we were unable to supply enough Cayston to fulfill our projected demand. From February through September 2012, we suspended access for patients with new prescriptions for Cayston, subject to certain exceptions where specific medical need existed. As a result of our inability to manufacture sufficient Cayston to meet demand, the amount of revenues we received from the sale of Cayston was reduced.

Our manufacturing operations are subject to routine inspections by regulatory agencies. For example, in April 2013, the FDA conducted an inspection of our Foster City facility and issued Form 483 Inspectional Observations, which noted deficiencies in documentation and validation of certain quality testing procedures and methods. As a result of the observations, the FDA delivered Complete Response Letters notifying us that it was unable to approve our NDAs for elvitegravir and cobicistat as standalone agents. In mid-October 2013, the FDA completed its sofosbuvir pre-approval inspection of our Foster City facility. Following that inspection, the FDA issued additional Form 483 Inspectional Observations citing deficiencies related to testing and reconciliation of stability samples, testing protocols, testing of shipping samples, and procedures for calibrating test equipment. We recently completed and filed our responses to these observations with the FDA. If we are unable to remedy the deficiencies cited by the FDA in these inspections, our currently marketed products and the timing of regulatory approval of products in development could be adversely affected. Further, there is risk that regulatory agencies in other countries where marketing applications are pending will undertake similar additional reviews or apply a heightened standard of review, which could delay the regulatory approvals for products in those countries. If approval of any of our product candidates, including idelalisib and LDV/SOF were delayed or if production of our marketed products was interrupted, our anticipated revenues and our stock price would be adversely affected.

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 processes. 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 certain drug product intermediates utilized in AmBisome 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 to meet market needs.

In addition, we depend on a single supplier for high-quality cholesterol and active pharmaceutical ingredient, which is used in the manufacture of AmBisome. We also rely on a single source for the active pharmaceutical ingredient 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 (Sovaldi, Stribild, Complera/Eviplera, Atripla, Truvada, Viread, Emtriva and Tybost) 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.

Litigation with generic manufacturers has reduced and may continue to reduce our earnings. If we are unsuccessful in all or some of these lawsuits, some or all of our claims in the patents may be narrowed or invalidated and generic versions of our products could be launched prior to our patent expiry.

As part of the approval process for some of our products, the FDA granted a New Chemical Entity (NCE) exclusivity period during which other manufacturers' applications for approval of generic versions of our product will not be approved. Generic manufacturers may challenge the patents protecting products that have been granted NCE exclusivity one year prior to the end of the NCE exclusivity period. Generic manufacturers have sought and may continue to seek FDA approval for a similar or identical drugs through an ANDA, the application form typically used by manufacturers seeking approval of a generic drug.

We received notices that generic manufacturers have submitted ANDAs to manufacture a generic version of Atripla, Truvada, Viread, Emtriva, Ranexa and Tamiflu in the United States and Atripla, Truvada and Viread in Canada. In April 2013, we and Teva Pharmaceuticals (Teva) reached an agreement to settle the ongoing patent litigation concerning the four patents that protect tenofovir disoproxil fumarate in our Atripla, Truvada and Viread products. Under the agreement, Teva will be allowed to launch a generic version of Viread on December 15, 2017.

In August 2013, we and Lupin Limited (Lupin) reached an agreement to settle the patent litigation concerning ten of the patents that protect Ranexa. Under the agreement, Lupin would be allowed to launch a generic version of Ranexa on February 27, 2019.

In February 2013, we and Teva reached an agreement in principle to settle the ongoing patent litigation concerning the emtricitabine patents that protect Atripla and Truvada. The terms of the settlement agreement are confidential. The settlement agreement will be filed with the Federal Trade Commission and Department of Justice as required by law.

Also in August 2012, Teva filed an Impeachment Action in the Federal Court of Canada seeking invalidation of our two Canadian patents associated with Viread. In September 2013, a hearing on the consolidated requests for orders of prohibition in connection with all three of Teva’s ANDS filings (for Teva’s generic versions of Viread, Truvada, and Atripla) took place. In December 2013, the court issued our requested order prohibiting the Canadian Minister of Health from issuing a Notice of Compliance for Teva’s generic versions of our Viread, Truvada, and Atripla products until expiry of our patent in July 2017. Teva appealed this decision and this decision of the court does not ultimately resolve the validity challenges raised by Teva in the Impeachment Action. If Teva is successful in invalidating our patents, Teva may be able to launch generic versions of our Viread, Truvada and Atripla products prior to the expiry of our patents. A trial in the Impeachment Action is scheduled for January 2015.

We anticipate trials related to Lupin's ANDAs requesting permission to make a generic version of Truvada and Viread and an ANDA filed by Cipla Ltd. requesting permission to make generic versions of Emtriva and Viread to take place in the fourth quarter of 2014.

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, Emtriva, Ranexa and Tamiflu in the United States and Atripla, Truvada and Viread in Canada could be substantially shortened. Further, if all of the patents covering one or more products are invalidated, the FDA or Canadian Minister of Health could approve the requests to manufacture a generic version of such products in the United States or Canada, respectively, prior to the expiration date of those patents. The sale of generic versions of these products earlier than their patent expiration would have a significant negative effect on our revenues and results of operations.

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, 2013, our accounts receivable in these countries totaled approximately $845.7 million of which, $402.4 million were past due greater than 120 days and $175.7 million were past due greater than 365 days as follows (in thousands):



	December 31, 2013
	Greater than 120 days past due		Greater than 365 days past due
Spain	$	286,477	$	136,712
Portugal	55,920		12,231
Italy	53,983		25,971
Greece	6,015		745
Total	$	402,395	$	175,659

Historically, receivable balances with certain publicly-owned hospitals accumulate over a period of time and are then subsequently settled as large lump sum payments. This pattern is also experienced by other pharmaceutical companies that sell directly to hospitals. 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.

In 2012, we collected $533.4 million in past due accounts receivable from customers based in Spain and Portugal. This included $349.7 million in proceeds from a one-time factoring arrangement where we sold receivables in Spain.

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. In March 2012, the Greek government restructured its sovereign debt which impacted all holders of Greek bonds. As a result, we recorded a $40.1 million loss.

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 more than 125 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 Indian generic manufacturers to distribute high-quality, low-cost generic versions of tenofovir disoproxil fumarate to 112 developing world countries, including India. We expanded these agreements to include rights to Stribild, Tybost and Vitekta. We also entered into collaborations with certain Indian generic manufacturers to produce and distribute generic emtricitabine in the developing world, including single tablet regimens containing emtricitabine and fixed-dose combinations of emtricitabine co-formulated with our other HIV medicines. 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.

We are involved in a number of litigation, investigation and other dispute-related matters that require us to expend substantial internal and financial resources. We expect these matters will continue to require a high level of internal and financial resources for the foreseeable future. These matters have reduced and will continue to reduce our earnings. Please see a description of our Litigation Regarding Sofosbuvir, Litigation with Generic Manufacturers and the Department of Justice investigation; in "Legal Proceedings" beginning on page 47. 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 our patents may not be enforced.

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 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. If we are required to grant compulsory licenses for our products, it could reduce our earnings and cash flows and harm our business.

In addition, 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. For example, 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, the Brazilian government now purchases its supply of tenofovir disoproxil fumarate from generic manufacturers. 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, Roche's Tamiflu sales have unpredictable variability due to their strong relationship with seasonal influenza and global pandemic planning efforts. During periods when our royalty revenue from Tamiflu increase, we will see a disproportionate increase in our pre-tax income, earnings per share and gross margins. Similarly, during periods when our royalty from Tamiflu decrease, we will see a disproportionate decrease in our pre-tax income, earnings per share and gross margins.

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 Fremont locations, which together house a majority of our R&D 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-tax deductible pharmaceutical excise tax, the accounting for stock options and other share-based payments, mergers and acquisitions, the ability to manufacture product in our Cork, Ireland facility, the amortization of certain acquisition related intangibles for which we receive no tax benefit, expiration of the federal research tax credit, 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 2010, 2011 and 2012 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

Our corporate headquarters is located in Foster City, California, where we house our administrative, manufacturing and R&D activities. We also have R&D facilities in Oceanside and Fremont, California; Seattle, Washington; Branford, Connecticut; and Alberta, Canada and manufacturing facilities in San Dimas, California and Cork, Ireland. Our global commercial operations include 20 offices throughout Europe, seven in Asia, one in South America and one in North America.

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

Litigation Regarding Sofosbuvir

In January 2012, we acquired Pharmasset, Inc. (Pharmasset). Through the acquisition, we acquired sofosbuvir (formerly known as GS-7977), a nucleotide analog that acts to inhibit the replication of HCV. In December 2013, we received U.S. Food and Drug Administration (FDA) approval of sofosbuvir, brand-named Sovaldi. We have received a number of contractual and intellectual property claims regarding sofosbuvir. We have carefully considered these claims both prior to and following the acquisition and believe they are without merit.

Contract Arbitration with Jeremy Clark

In March 2012, Jeremy Clark, a former employee of Pharmasset and inventor of U.S. Patent No. 7,429,572 patent, filed a demand for arbitration in his lawsuit against Pharmasset and Dr. Raymond Schinazi. Mr. Clark initially filed the lawsuit against Pharmasset and Dr. Schinazi in the U.S. District Court for the Northern District of Alabama in February 2008 seeking to void the assignment provision in his employment agreement and assert ownership of U.S. Patent No. 7,429,572 patent, which claims metabolites of sofosbuvir and RG7128. In December 2008, the court ordered a stay of the litigation pending the outcome of an arbitration proceeding required by Mr. Clark's employment agreement. Instead of proceeding with arbitration, Mr. Clark filed two additional lawsuits in September 2009 and June 2010, both of which the court subsequently dismissed. In September 2010, Mr. Clark filed a motion seeking reconsideration of the court's December 2008 order which the court denied. In December 2011, Mr. Clark filed a motion to appoint a special prosecutor. In February 2012, the court issued an order requiring Mr. Clark to enter arbitration or risk dismissal of his case. Mr. Clark filed a demand for arbitration in March 2012. The arbitration panel held a hearing in April 2013. In June 2013, the arbitration panel issued its decision in favor of Pharmasset (now Gilead) and Dr. Schinazi. In August 2013, Gilead and Dr. Schinazi filed a motion in the U.S. District Court for the Northern District of Alabama seeking to have the court confirm the arbitration decision and Mr. Clark filed a motion seeking to vacate the arbitration decision. The court has not yet ruled on these motions.

Arbitration with F. Hoffman-La Roche Ltd and Hoffman-La Roche Inc. (collectively, Roche)

raised by Roche and that it believed any such issues are without merit. We have also considered these issues and reached the same conclusion. In March 2013, Roche initiated an arbitration against us and Pharmasset, predecessor to Gilead Pharmasset LLC, regarding the collaboration agreement. In the arbitration demand, Roche asserts that it has an exclusive license to sofosbuvir pursuant to the collaboration agreement because sofosbuvir, a prodrug of a uridine monophosphate analog, is allegedly a prodrug of PSI-6130, a cytidine analog. Roche further claims that, because it has exclusive rights to sofosbuvir, it also has an exclusive license to a patent covering sofosbuvir, and that we will infringe that patent by selling and offering for sale products containing sofosbuvir. Gilead and Gilead Pharmasset LLC filed their response to Roche's arbitration demand in April 2013.

Interference Proceedings and Litigation with Idenix Pharmaceuticals, Inc.

claim the benefit of the filing date of its earlier filed patent applications. We believe the Board’s determination in the First Idenix Interference that Idenix is not entitled the benefit of any of its earlier application filing dates, including the filing date of the ‘600 patent, will be equally applicable to the Second Idenix Interference. If we are correct, the Board may conclude that Gilead is the senior party in the Second Idenix Interference, consistent with the determination in the First Idenix Interference. In light of the Board’s conclusion in the First Idenix Interference that the application that led to the ‘600 patent does not teach how to make the claimed compounds, it is possible that the Board will make the same determination in the Second Idenix Interference and eliminate the need for the Board to address who was the first to invent the claimed methods of treating HCV. However, if the Board does consider who was the first to invent the claimed methods of treating HCV and ultimately concludes that Gilead was first, the claims in the '600 patent may be revoked. If the Board determines that Idenix was first to invent and is entitled to these patent claims, and it is determined in other proceedings that we have infringed those claims, we may be required to obtain a license from and pay royalties to Idenix to commercialize sofosbuvir and RG7128. Any determination by the Board can be appealed by either party to U.S. federal court.

Litigation with Merck & Co., Inc.

Litigation with AbbVie, Inc. (AbbVie)

be required to obtain a license from and pay royalties to AbbVie to commercialize sofosbuvir combination products. Either party can appeal a decision by the District Court to the CAFC.

Litigation with Generic Manufacturers

As part of the approval process for some of our products, the FDA granted a New Chemical Entity (NCE) exclusivity period during which other manufacturers' applications for approval of generic versions of our product will not be approved. Generic manufacturers may challenge the patents protecting products that have been granted NCE exclusivity one year prior to the end of the NCE exclusivity period. Generic manufacturers have sought and may continue to seek FDA approval for a similar or identical drugs through an ANDA, the application form typically used by manufacturers seeking approval of a generic drug.

Tenofovir Disoproxil Fumarate, Emtricitabine and Fixed-dose Combination of Emtricitabine, Tenofovir Disoproxil Fumarate and Efavirenz

In November 2008, we received notice that Teva Pharmaceuticals (Teva) submitted an abbreviated new drug application (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, 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 fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate. In December 2008, we filed a lawsuit in U.S. District Court for the Southern District of 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 fixed-dose combination of emtricitabine, tenofovir disoproxil fumarate and efavirenz. In the notice, Teva challenged the same two emtricitabine patents. In May 2009, we filed another lawsuit in U.S. District Court for the Southern District of 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 generic versions of our Atripla and Truvada products. In the notice related to Teva's ANDA for a generic version of 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 Teva's ANDA for a generic version of Truvada, Teva challenged four patents related to tenofovir disoproxil fumarate and two additional patents related to emtricitabine. In March 2010, we filed lawsuits against Teva for infringement of the four Viread patents and two additional emtricitabine patents. In March 2010, Bristol-Myers Squibb Company and Merck filed a lawsuit against Teva for infringement of the patents related to efavirenz. Because we filed our lawsuits within the requisite 45-day period provided in the Hatch Waxman Act, there were stays preventing FDA approval of Teva's ANDAs for 30 months or until a district court decision adverse to the patents. The 30-month stay for all three Teva ANDAs expired in July 2012. In April 2013, we and Teva reached an agreement to settle the ongoing patent litigation concerning the four patents that protect tenofovir disoproxil fumarate in Atripla, Truvada and Viread. Under the agreement, Teva will be allowed to launch a generic version of Viread on December 15, 2017. The settlement agreement was filed with the Federal Trade Commission and Department of Justice as required by law. On October 1, 2013, the court’s dismissal of the case pursuant to the settlement agreement between the parties became final. A trial in the lawsuit against Teva related to the U.S. patents protecting emtricitabine in Atripla and Truvada was held in October 2013. In February 2014, we and Teva reached an agreement in principle to settle the ongoing patent litigation concerning the emtricitabine patents that protect Atripla and Truvada. The terms of the settlement agreement are confidential. The settlement agreement will be filed with the Federal Trade Commission and Department of Justice as required by law.

generic version of Viread. In the notice, Teva alleges that two patents associated with tenofovir disoproxil fumarate are invalid, unenforceable and/or will not be infringed by Teva's manufacture, use or sale of a generic version of Viread, Truvada, and Atripla. In September 2012, we filed a lawsuit against Teva in the Federal Court of Canada seeking an order of prohibition against approval of this ANDS. Also in August 2012, Teva filed an Impeachment Action in the Federal Court of Canada seeking invalidation of our two Canadian patents associated with Viread. We are currently defending that Impeachment Action. The requests for orders of prohibition in connection with all three of Teva’s ANDS filings (for Teva’s generic versions of Viread, Truvada and Atripla) were consolidated and a hearing on the consolidated requests for the orders of prohibition took place in September 2013. In December 2013, the court issued our requested order prohibiting the Canadian Ministry of Health from issuing a Notice of Compliance for Teva’s generic versions of our Viread, Truvada and Atripla products until expiry of our patent in July 2017. Teva has appealed this decision and this decision does not ultimately resolve the validity challenges raised by Teva in the Impeachment Action. If Teva is successful in invalidating our patents, Teva may be able to launch generic versions of our Viread, Truvada and Atripla products prior to the expiry of our patents. A trial in the Impeachment Action is scheduled for January 2015.

Ranolazine

Tamiflu

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 oseltamivir phosphate 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. (Roche) filed a lawsuit against Natco in U.S. District Court for the District of New Jersey for infringement of one of the patents associated with Tamiflu. In December 2012, the court issued a ruling in favor of Gilead and Roche, that our patent is not invalid for the reasons stated in

Natco's notice letter. Natco has appealed this decision to the CAFC. A hearing on Natco’s appeal took place in January 2014. The court has not yet issued a decision in this appeal. If Natco is successful in the appeal, the case will be remanded to the U.S. District Court for the District of New Jersey for a full trial on the merits.

Department of Justice Investigation

In June 2011, we received a subpoena from the U.S. Attorney's Office for the Northern District of California requesting documents related to the manufacture, and related quality and distribution practices, of Complera, Atripla, Truvada, Viread, Emtriva, Hepsera and Letairis. We have been cooperating and will continue to cooperate with this governmental inquiry.

Other Matters

We are a party to various legal actions that arose in the ordinary course of our business. We do not believe that these other 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
2013
First Quarter	$49.48	$36.94
Second Quarter	$58.07	$46.53
Third Quarter	$64.74	$51.42
Fourth Quarter	$76.11	$58.81
2012
First Quarter	$28.02	$20.93
Second Quarter	$26.36	$22.71
Third Quarter	$33.88	$25.33
Fourth Quarter	$38.17	$32.43

As of February 14, 2014, we had 1,538,252,914 shares of common stock outstanding held by approximately 381 stockholders of record, which include shares held by a broker, bank or other nominee.

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.

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&P 500 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&P 500 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&P 500 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⁾


⁽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&P 500 Index on December 31, 2008.

Issuer Purchases of Equity Securities

As of December 31, 2013, we have repurchased $1.65 billion of our common stock under our January 2011, three-year, $5.00 billion stock repurchase program, which will expire in September 2014. During 2013, we spent a total of $582.2 million to repurchase and retire approximately 9.6 million shares of our common stock at an average purchase price of $60.78 per share. See Item 8, Note 12, Stockholders' Equity in 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, 2013 (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 Program	⁽¹⁾	Maximum Fair Value of Shares that May Yet Be Purchased Under the Program		⁽¹⁾
October 1 - October 31, 2013	2,561		$	65.28	2,511		$	3,583,884
November 1 - November 30, 2013	2,212		$	69.86	1,938		$	3,447,902
December 1 - December 31, 2013	1,403		$	72.44	1,381		$	3,347,876
Total	6,176	⁽²⁾	$	68.55	5,830	⁽²⁾


⁽¹⁾	In January 2011, we announced that our Board authorized a three-year, $5.00 billion stock repurchase program, which will expire in September 2014.


⁽²⁾	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,
	2013		2012		2011		2010		2009
CONSOLIDATED STATEMENT OF INCOME DATA:
Total revenues	$	11,201,688	$	9,702,517	$	8,385,385	$	7,949,420	$	7,011,383
Total costs and expenses ⁽¹⁾	$	6,677,689	$	5,692,342	$	4,595,544	$	3,987,198	$	3,482,162
Income from operations	$	4,523,999	$	4,010,175	$	3,789,841	$	3,962,222	$	3,529,221
Provision for income taxes	$	1,150,933	$	1,038,381	$	861,945	$	1,023,799	$	876,364
Net income attributable to Gilead	$	3,074,808	$	2,591,566	$	2,803,637	$	2,901,257	$	2,635,755
Net income per share attributable to Gilead common stockholders-basic	$	2.01	$	1.71	$	1.81	$	1.69	$	1.46
Shares used in per share calculation-basic	1,528,620		1,514,621		1,549,806		1,712,120		1,809,208
Net income per share attributable to Gilead common stockholders-diluted	$	1.81	$	1.64	$	1.77	$	1.66	$	1.41
Shares used in per share calculation-diluted	1,694,747		1,582,549		1,580,236		1,746,792		1,868,218



	December 31,
	2013		2012		2011		2010		2009
CONSOLIDATED BALANCE SHEET DATA:
Cash, cash equivalents and marketable securities	$	2,570,590	$	2,582,086	$	9,963,972	$	5,318,071	$	3,904,846
Working capital ⁽²⁾	$	948,332	$	1,918,450	$	11,431,584	$	3,271,267	$	2,963,066
Total assets ⁽³⁾	$	22,496,785	$	21,239,838	$	17,303,134	$	11,592,630	$	9,698,559
Other long-term obligations ⁽²⁾	$	156,647	$	249,973	$	175,325	$	55,536	$	58,057
Convertible senior notes, senior unsecured notes and credit facility ⁽⁴⁾	$	6,635,678	$	8,223,988	$	7,605,734	$	3,477,564	$	1,155,443
Retained earnings	$	6,105,244	$	3,704,744	$	1,776,760	$	1,183,730	$	1,995,272
Total stockholders' equity ⁽²⁾	$	11,744,501	$	9,543,722	$	6,867,349	$	6,121,837	$	6,505,158



⁽¹⁾		During 2012, we recorded $100.1 million and $93.8 million of stock-based compensation in research and development (R&D) expenses and selling, general and administrative expenses, respectively, related to the acquisition of Pharmasset, Inc. (Pharmasset).
		During 2011, we recorded $26.6 million of impairment charges in R&D expenses related to certain in-process research and development (IPR&D) assets acquired from CGI Pharmaceuticals, Inc.
		During 2010, we recorded $136.0 million of impairment charges in R&D expenses related to certain IPR&D assets acquired from CV Therapeutics, Inc. (CV Therapeutics).
⁽²⁾		Certain prior period amounts have been reclassified to conform to the current presentation.
⁽³⁾		During 2012, we completed the acquisition of Pharmasset and we recognized consideration transferred of $11.05 billion which was primarily recorded in intangible assets. We financed the transaction with approximately $5.20 billion in cash on hand, $2.15 billion in bank debt issued in January 2012 and $3.70 billion in senior unsecured notes issued in December 2011.
		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.
⁽⁴⁾		During 2013, we repaid $1.52 billion of principal balance of convertible senior notes and repaid $150.0 million under the five-year revolving credit facility credit agreement (the Five-Year Revolving Credit Agreement).
		During 2012, we borrowed $750.0 million under our Five-Year Revolving Credit Agreement.
		During 2011, we issued $4.70 billion principal amount of senior unsecured notes in registered offerings.
		During 2010, we issued $2.50 billion principal amount of convertible senior notes in a private placement.


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 strive to transform and simplify care for people with life-threatening illnesses around the world. Gilead's primary areas of focus include human immunodeficiency virus (HIV), liver diseases such as hepatitis B virus (HBV) infection and hepatitis C virus (HCV) infection, oncology/inflammation and serious cardiovascular and respiratory conditions. Headquartered in Foster City, California, we have operations in North and South America, Europe and Asia-Pacific. We continue 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 Stribild^®, Complera^®/Eviplera^®, Atripla^®, Truvada^®, Viread^®, Emtriva^®, Tybost^®, Sovaldi^®, Hepsera^®, Vitekta^®, Letairis^®, Ranexa^®, Cayston^®, AmBisome^® and Vistide^®.

Business Highlights

During 2013, we continued to advance our product pipeline across all therapeutic areas. We made significant progress, particularly in our Phase 3 studies in oncology, liver diseases and HIV. The combination of our existing internal research programs, acquisitions and partnerships will allow us to continue bringing innovative therapies to individuals who are living with unmet medical needs. Below is a summary of our key accomplishments:


•	expanded our single tablet regimen (STR) products with the European launch of Stribild in 14 countries;


•	received U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) approval of Complera/Eviplera for use among certain adult patients switching from another stable antiretroviral regimen;


•	received EMA approval for once-daily Tybost, a pharmacokinetic enhancer that boosts blood levels of certain HIV medicines;


•	received EMA approval for Vitekta, an integrase inhibitor for the treatment of HIV-1 infection in adults without known mutations associated with resistance to elvitegravir;


•	advanced the clinical development of tenofovir alafenamide (TAF) as a once-daily single tablet regimen for the treatment of HIV-1 infection to Phase 3 clinical trials;


•	received approval from the FDA and Health Canada in December 2013 for Sovaldi (sofosbuvir), a once daily oral regimen for the treatment of HCV as a component of a combination of antiviral treatment regimens; received approval from the EMA for Sovaldi in January 2014;


•	announced positive interim results from three Phase 3 clinical studies (ION-1, ION-2 and ION-3) evaluating the once-daily fixed-dose combination of ledipasvir/sofosbuvir (LDV/SOF), with and without ribavirin (RBV), for the treatment of genotype 1 HCV infection; filed a new drug application (NDA) for the fixed-dose combination of LDV/SOF in February 2014;

•

submitted an NDA to the FDA for approval of idelalisib for the treatment of patients with indolent non-Hodgkin's lymphoma (iNHL) and chronic lymphocytic leukemia (CLL). We also filed for approval of idelalisib for treatment of iNHL and CLL with the EMA on October 28, 2013. In January 2014, the FDA accepted our NDA for iNHL and set a target review date of September 11, 2014 under the Prescription Drug User Fee Act (PDUFA). In February 2014, the FDA, which previously granted Breakthrough Therapy designation for idelalisib in CLL, accepted our NDA and set a target review date of August 6, 2014 under the PDUFA; and


•	completed the acquisition of YM Biosciences Inc. (YM), through which we acquired momelotinib, an orally administered, once-daily candidate for hematologic cancers and advanced the clinical development of momelotinib to Phase 3 clinical trials.

Outlook 2014

In 2014, we will continue to focus on our key operating objectives which include continued progression of our product pipeline and continued uptake of our commercial products. From a research and development (R&D) perspective, we will continue to invest in our various ongoing clinical studies, which support both our existing products and pipeline of new drug candidates. We expect to move forward on a number of late-stage clinical studies for new product candidates and plan to file

marketing applications for various therapeutic areas.

From a commercial perspective, during 2013, we began to build-out our commercial organization to support the launch of Sovaldi in the United States and Canada in December 2013. In January 2014, we received approval from the EMA for Sovaldi in all 28 countries of the European Union. Sovaldi represents a significant shift in the treatment paradigm for certain HCV patients around the world. During 2014, we plan to further the build-out and expansion of our international commercial infrastructure particularly in Europe and Asia to support the Sovaldi launches and increase marketing and sales efforts related to the anticipated launch of our first oncology product, idelalisib.

We continue to monitor conditions in the macroeconomic environment that could affect our ability to achieve our goals, such as changes in the reimbursement and payor landscape as well as legislation that may delay or impact funding for AIDS Drug Assistance Programs (ADAPs) in the United States, a worsening of economic conditions in certain key markets, particularly in Europe, patent expirations of competitive products and the launch of generic competitors, government pricing pressures internationally and the potential volatility in foreign currency exchange rates. We will adjust our business processes, as appropriate, to attempt to mitigate these risks to our business.

We expect that our product pipeline investments and expanding commercial infrastructure will enable us to execute on our 2014 operating objectives.

2013 Financial Highlights

During 2013, we delivered strong financial performance and continued to invest in our product pipeline. Total revenues grew 15% to $11.20 billion and total product sales grew 15% to $10.80 billion, compared to 2012 driven primarily by an increase in antiviral product sales.

R&D expenses increased 20% to $2.12 billion for 2013 compared to 2012 due to progression of our clinical studies, particularly Phase 3 studies in oncology, liver diseases and HIV. Selling, general and administrative (SG&A) expenses increased 16% to $1.70 billion for 2013 compared to 2012 due to the ongoing growth and expansion of our business, including commercial expansion related to the launch of Sovaldi.

Net income attributable to Gilead for 2013 was $3.07 billion or $1.81 per diluted share, compared to $2.59 billion or $1.64 per diluted share in 2012, due to the increase in total revenues, partially offset by an increase in R&D and SG&A expenses.

During 2013, we generated $3.10 billion in operating cash flows, paid $1.04 billion for the warrants related to our May 2013 Notes that settled in August 2013, repaid $1.67 billion in debt net of proceeds from convertible note hedges and utilized $378.6 million for the acquisition of YM, net of cash acquired.

Results of Operations

Total Revenues

Total revenues include product sales, royalty revenues, and contract and other revenues. Total revenues increased 15% to $11.20 billion in 2013, compared to 2012 and increased 16% to $9.70 billion in 2012 compared to $8.39 billion in 2011. Product sales represented 96% of total revenues in 2013 and 97% of total revenues in 2012 and 2011. Royalty revenues represented 3% of total revenues during 2013, 2012 and 2011.

Product Sales

Total product sales were $10.80 billion in 2013, an increase of 15% over total product sales of $9.40 billion in 2012, driven primarily by the continued uptake of our STR products, primarily Stribild and Complera/Eviplera. Cardiovascular product sales consisting of Letairis and Ranexa, increased 24% to $968.6 million in 2013 compared to $783.0 million in 2012. Total product sales were $9.40 billion in 2012, an increase of 16% over total product sales of $8.10 billion in 2011, driven primarily by continued growth in sales of our antiviral products, including Atripla, Truvada and Complera/Eviplera.

Product sales in the United States increased 20% for 2013 to $6.65 billion compared to $5.54 billion in 2012, driven by sales growth of our STR products, specifically Stribild and Complera as well as the launch of our newest product, Sovaldi.

During the fourth quarters of 2013 and 2012, we noted strong wholesaler and sub-wholesaler purchases in anticipation of price increases effective January 1. We estimate that during the fourth quarter of 2013, sales exceeded demand by approximately $130 - $150 million and $80 - $100 million during the same period in 2012. Based on our observations during the first quarter of 2013, this may result in inventory draw-downs during the first quarter of 2014.

Approximately 40% of our product sales are generated outside the United States and as a result, we face exposure to adverse movements in foreign currency exchange rates, primarily in the Euro. We used foreign currency exchange forward contracts to hedge a percentage of our foreign currency exposure. Foreign currency exchange, net of hedges, had an unfavorable impact of $64.8 million on our 2013 revenues compared to 2012 and an unfavorable impact of $57.1 million on our 2012 revenues compared to 2011.

Product sales in Europe increased 6% in 2013 to $3.33 billion compared to $3.14 billion in 2012, driven primarily by higher underlying demand for our antiviral products, specifically Eviplera, partially offset by decreases in the average net selling price. Product sales in Europe increased 6% in 2012 to $3.14 billion compared to $2.96 billion in 2011, driven primarily by higher underlying demand in our antiviral franchise. Antiviral product sales in Europe totaled $2.87 billion in 2012, an increase of 6% compared to $2.71 billion in 2011, driven primarily by the sales of Atripla and Truvada. Foreign currency exchange, net of hedges, had an unfavorable impact of $55.3 million on our European product sales in 2013 compared to 2012 and an unfavorable impact of $68.9 million on our European product sales in 2012 compared to 2011.

In light of the fiscal and debt crises experienced by several countries in the European Union, several governments have announced or implemented measures to manage healthcare expenditures. Although to date, we have paid rebates in countries outside the United States, payments made to foreign governments do not represent a significant portion of our government rebates and chargebacks or percentage of total product sales in foreign locations. However, we continue to experience pricing pressure, such as increases in the amount of discounts required on our products and delayed reimbursement which could negatively impact our future product sales and results of operations.

We expect our total product sales to grow in 2014, as we realize the full year impact of sales of Sovaldi and continued uptake of our commercial products, primarily our single tablet regimens. We believe this growth could be tempered by pricing pressures in certain European territories, the impact of generic efavirenz, now available in Canada and Europe, potential volatility in foreign currency exchange rates and changes in the macroeconomic environment.

Government Rebates and Chargebacks

U.S. government rebates and chargebacks deducted from gross product sales increased 19% to $3.08 billion in 2013 from $2.59 billion in 2012 and increased 39% from $1.86 billion in 2011, representing 21% of total gross product sales in both 2013 and 2012 and 17% of total gross product sales in 2011. In March 2010, healthcare reform legislation was adopted in the United States that required further rebates or discounts on products reimbursed or paid for by various public payers, such as Medicaid and other entities eligible to purchase discounted products. As a result of this legislation and the impact of the economic downturn, our total rebates and chargebacks have increased as we have experienced changes in our payer mix. Specifically, we believe that certain patients previously covered by private insurance have moved to public reimbursement programs. As a result, we expect government rebates and chargebacks as a percentage of total gross product sales will continue to increase.

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



(In thousands, except percentages)	2013		Change		2012		Change		2011
Antiviral products:
Atripla	$	3,648,496	2	%	$	3,574,483	11	%	$	3,224,518
Truvada	3,135,771		(1	)%	3,181,110		11	%	2,875,141
Viread	958,969		13	%	848,697		15	%	737,867
Complera/Eviplera	809,452		137	%	342,200		783	%	38,747
Stribild	539,256		837	%	57,536		—	%	—
Sovaldi	139,435		—	%	—		—	%	—
Hepsera	81,095		(25	)%	108,315		(25	)%	144,679
Emtriva	27,405		(7	)%	29,449		2	%	28,764
Total antiviral products	9,339,879		15	%	8,141,790		15	%	7,049,716
Letairis	519,966		27	%	410,054		40	%	293,426
Ranexa	448,624		20	%	372,949		17	%	320,004
AmBisome	351,827		1	%	346,646		5	%	330,156
Other products	143,399		13	%	126,932		16	%	109,057
Total product sales	$	10,803,695	15	%	$	9,398,371	16	%	$	8,102,359

Antiviral Products

Antiviral product sales increased by 15% in 2013 compared to 2012 and 2012 compared to 2011.


•	Atripla

In 2013, increases in Atripla sales were driven primarily by an increase in the average net selling price. In 2012, Atripla sales were driven primarily by sales volume growth in the United States. Atripla sales accounted for 39%, 44% and 46% of our total antiviral product sales for 2013, 2012 and 2011, respectively. The efavirenz component of Atripla, which has a gross margin of zero, comprised $1.40 billion, $1.34 billion and $1.21 billion of our Atripla sales in 2013, 2012 and 2011, respectively.

A generic version of Bristol-Myers Squibb Company's Sustiva (efavirenz), a component of our Atripla, was made available in Canada and Europe in 2013 and will be made available in the United States in 2015. As a result, we expect increased competitive pricing pressure on our future Atripla sales.


•	Truvada

In 2013, decreases in Truvada sales were due to a decrease in sales volume, partially offset by an increase in average net selling price. In 2012, Truvada sales were driven primarily by sales volume growth in the United States. Truvada sales accounted for 34%, 39% and 41% of our total antiviral product sales for 2013, 2012 and 2011, respectively. Future sales of Truvada could be impacted by patients switching to a different STR regimen.


•	Complera/Eviplera

In 2013, increases in Complera/Eviplera sales were driven primarily by sales volume growth in Europe and the United States. In 2012, Complera/Eviplera sales increased due primarily to sales volume growth in the United States. Complera was approved in the United States in August 2011, and Eviplera was approved in the European Union in November 2011. During 2013, we estimate that Complera became the number two most-prescribed regimen in treatment naïve HIV patients in the United States and the number one most-prescribed regimen in treatment naïve HIV patients in Europe's Big 5 markets, the United Kingdom, France, Germany, Italy and Spain.


•	Stribild

In 2013 and 2012, increases in sales of Stribild were driven primarily by sales volume growth in the United States. Stribild was approved in the United States in August 2012 and in Europe in May 2013. During 2013, we estimate that Stribild became the number one most-prescribed regimen in treatment naïve HIV patients in the United States.


•	Sovaldi

In December 2013, the FDA approved Sovaldi for the treatment of HCV. Sovaldi sales totaled $139.4 million in 2013, of which we estimate that approximately half related to initial inventory stocking by wholesalers and sub-wholesalers.

Cardiovascular Products

Our cardiovascular products, which include Letairis and Ranexa increased due primarily to sales volume growth.

Royalty Revenues

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



(In thousands, except percentages)	2013		Change		2012		Change		2011
Royalty revenues	$	383,849	32	%	$	290,523	8	%	$	268,827

Royalty revenues increased 32% for 2013 compared to 2012, due to higher royalty revenues from F. Hoffmann-La Roche Ltd (Roche) as a result of an increase in the number of patients treated for influenza with Tamiflu. Royalty revenues increased 8% for 2012 compared to 2011, driven primarily by higher royalty revenues from GlaxoSmithKline, Inc., Japan Tobacco Inc. and Astellas US LLC partially offset by lower Tamiflu royalties from Roche. Tamiflu royalties from Roche contributed $134.7 million, $43.7 million and $75.5 million to total royalty revenues in 2013, 2012 and 2011 respectively. We recognize royalties on Tamiflu sales by Roche in the quarter following the quarter in which the corresponding sales occur.

Cost of Goods Sold and Product Gross Margin

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



(In thousands, except percentages)	2013			Change		2012			Change		2011
Total product sales	$	10,803,695		15	%	$	9,398,371		16	%	$	8,102,359
Cost of goods sold	$	2,858,502		16	%	$	2,471,363		16	%	$	2,124,410
Product gross margin	74		%			74		%			74		%

Our product gross margin for 2013 was consistent with our product gross margin for 2012 and 2011. Our product gross margin for the fourth quarter of 2013 was 71.8% and included $58.3 million in amortization expense related to the transition of the in-process research and development (IPR&D) asset, from an indefinite-lived to finite-lived intangible asset upon the FDA approval and commercial launch of Sovaldi. In 2014, we expect to recognize the full year impact of amortization of approximately $700.0 million related to Sovaldi.

Research and Development Expenses

The following table summarizes the period over period changes in R&D expenses:



(In thousands, except percentages)	2013		Change		2012		Change		2011
Research and development	$	2,119,756	20	%	$	1,759,945	43	%	$	1,229,151

We do not track total R&D expenses by product candidate, therapeutic area or development phase. However, we manage our R&D expenses by identifying the R&D 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 considerations. We continually review our R&D pipeline and the status of development and, as necessary, reallocate resources among the R&D product portfolio that we believe will best support the future growth of our business.

R&D expenses summarized above consist primarily of clinical studies performed by contract research organizations (CROs), materials and supplies, licenses and fees, milestone payments under collaboration arrangements, personnel costs, including salaries, benefits and stock-based compensation 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, except percentages)	2013		2012		2011
Clinical studies and outside services	$	1,147,169	$	828,278	$	570,302
Personnel and infrastructure expenses	714,027		686,091		412,463
Facilities, IT and other costs	258,560		245,576		219,756
In-process research and development impairment charges	—		—		26,630
Total	$	2,119,756	$	1,759,945	$	1,229,151

In 2013, R&D expenses increased $359.8 million or 20% compared to 2012, due primarily to a $318.9 million increase in clinical studies and a $27.9 million increase in personnel and infrastructure expenses to support the continued progression of our clinical studies, particularly Phase 3 studies in oncology, liver diseases and HIV. These increases were partially offset by a $100.1 million decrease in stock-based compensation expense due to the acceleration of vested stock options related to our acquisition of Pharmasset, Inc. (Pharmasset) in January 2012.

In 2012, clinical studies and outside services increased $258.0 million compared to 2011 due to progression and expansion of our Phase 3 studies, particularly in liver diseases and oncology. Additionally, personnel expenses increased $273.6 million due to higher headcount to support our product pipeline and study progression.

During 2011, we recorded $26.6 million of impairment charges related to certain IPR&D assets acquired from CGI Pharmaceuticals, Inc.. These impairment charges were a result of changes in the anticipated market share related to the spleen tyrosine kinase (Syk) compound.

In 2014, we expect R&D expenses to increase over 2013 due primarily to continued investment in advancing our product pipeline, driven primarily by the progression of our clinical studies in oncology, liver diseases and HIV.

Selling, General and Administrative Expenses

The following table summarizes the period over period changes in SG&A expenses:



(In thousands, except percentages)	2013		Change		2012		Change		2011
Selling, general and administrative	$	1,699,431	16	%	$	1,461,034	18	%	$	1,241,983

SG&A expenses relate to sales and marketing, finance, human resources, legal and other administrative activities. Expenses are primarily comprised of facilities and overhead costs, outside marketing, advertising and legal expenses and other general and administrative costs.

In 2013, SG&A expenses increased $238.4 million or 16% compared to 2012. The increase was due primarily to a $308.0 million increase in headcount-related and other expenses to support the ongoing growth of our business, legal expenses and pharmaceutical excise tax resulting from U.S. healthcare reform. This increase was partially offset by a $98.0 million decrease in stock-based compensation due to the acceleration of vested stock options related to our acquisition of Pharmasset in January 2012. Sequentially, SG&A expenses in the fourth quarter of 2013 increased $106.4 million or 26% compared to the third quarter of 2013 due primarily to increased marketing activities related to the launch of Sovaldi.

In 2012, SG&A expenses increased $219.1 million or 18% compared to 2011. The increase was due primarily to a $100.5 million increase in costs associated with the growth of our business which include personnel and headcount-related expenses, a $98.0 million increase in stock-based compensation expenses primarily resulting from the acquisition of Pharmasset and an increase of $38.2 million in the pharmaceutical excise tax resulting from U.S. healthcare reform. This increase was partially offset by a reduction in bad debt provisions of $34.3 million, which included a gain of $29.9 million related to the sale of our accounts receivables balances in Spain in the second quarter of 2012.

In 2014, we expect SG&A expenses to increase over 2013 to support our continued build-out and expansion of our commercial infrastructure in Europe and Asia to support our Sovaldi launches, increased sales and marketing efforts related to the anticipated launch of our first oncology product, idelalisib and an increase in the pharmaceutical excise tax. We estimate our portion of the pharmaceutical excise tax to be approximately $150 - $170 million in 2014, compared to approximately $110 million in 2013 and approximately $85 million in 2012.

Interest Expense

In 2013, interest expense decreased to $306.9 million compared to $360.9 million in 2012. The decrease was due primarily to the repayment of our May 2013 Notes, conversions of our convertible senior notes due in May 2014 and May 2016 (May 2014 Notes and May 2016 Notes), and the repayment of revolving credit facilities. In 2012, interest expense increased to $360.9 million compared to $205.4 million in 2011. The increase was due primarily to the additional debt we issued in connection with our acquisition of Pharmasset, which included $3.70 billion in senior unsecured notes issued in December 2011 and $2.15 billion in bank debt issued in January 2012.

Other Income (Expense), Net

For 2013, other income (expense), net was a net expense of $(8.9) million compared to a net expense of $(37.3) million in 2012 and net income of $66.6 million in 2011. The changes in other income (expense), net were due primarily to a $40.1 million loss on Greek bonds related to Greece's restructuring of its sovereign debt in the first quarter of 2012.

Provision for Income Taxes

Our provision for income taxes was $1.15 billion, $1.04 billion and $861.9 million in 2013, 2012 and 2011, respectively. The 2013 effective tax rate of 27.3% differed from the U.S. federal statutory rate of 35% due primarily to the retroactive extension of the 2012 federal research tax credit in January 2013, the 2013 federal research tax credit and certain operating earnings from non-U.S. subsidiaries that are considered indefinitely reinvested, partially offset by state taxes, our portion of the non-tax deductible pharmaceutical excise tax and amortization expense related to the Pharmasset acquisition and contingent consideration expense related to certain acquisitions for which we receive no tax benefit. We do not provide for U.S. income taxes on undistributed earnings of our foreign operations that are intended to be indefinitely reinvested in our foreign subsidiaries.

The 2012 effective tax rate of 28.7% 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 reinvested, partially offset by state taxes, the stock-based compensation expense related to the Pharmasset acquisition and contingent consideration expense related to certain acquisitions for which we receive no tax benefit.

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 reinvested, partially offset by state taxes and the non-tax deductible pharmaceutical excise tax.

Our future effective tax rate may be impacted by various factors, including the amortization of certain acquisition-related intangibles for which we receive no tax benefit.

Acquisitions

YM Biosciences Inc.

We completed the acquisition of YM BioSciences Inc. (YM), based in Canada, for total consideration transferred of $487.6 million on February 8, 2013, at which time YM became a wholly-owned subsidiary of Gilead. YM was a drug development company primarily focused on advancing momelotinib (formerly known as CYT387), an orally administered, once-daily candidate for hematologic cancers.

The fair values of acquired assets and assumed liabilities include primarily IPR&D of $362.7 million, goodwill of $127.2 million, deferred tax assets of $53.0 million with a full unrecognized tax benefit, deferred tax liabilities of $108.8 million and cash acquired of $108.9 million. Pro forma results of operations for the acquisition of YM have not been presented because this acquisition is not material to our consolidated results of operations. See Note 8, Intangible Assets and Goodwill for a description of the IPR&D acquired.

Pharmasset, Inc.

In January 2012, we completed the acquisition of Pharmasset, a publicly-held clinical-stage pharmaceutical company 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. Pharmasset's lead compound sofosbuvir (formerly known as GS-7977), is a nucleotide analog which, in December 2013, was approved by the FDA and Health Canada under the name Sovaldi, as a once-daily oral regimen for the treatment of HCV in patients with genotypes 1, 2, 3 or 4 infection, including those with hepatocellular carcinoma meeting Milan criteria (awaiting liver transplantation) and those with HCV/HIV-1 co-infection. In January 2014, the European Commission granted marketing authorization for Sovaldi in all 28 countries in the European Union. The acquisition of Pharmasset has allowed us to advance our effort to develop all-oral regimens for the treatment of HCV.

We acquired all of the outstanding shares of common stock of Pharmasset for $137 per share in cash through a tender offer and subsequent merger under the terms of an agreement and plan of merger entered into in November 2011. The aggregate cash payment to acquire all of the outstanding shares of common stock was $11.05 billion. We financed the transaction with approximately $5.20 billion in cash on hand, $3.70 billion in senior unsecured notes issued in December 2011 and $2.15 billion in bank debt issued in January 2012.

The Pharmasset acquisition was accounted for as a business combination. The results of operations of Pharmasset have been included in our Consolidated Statement of Income since January 13, 2012, the date on which we acquired approximately 88% of the outstanding shares of common stock of Pharmasset, cash consideration was transferred, and as a result, we obtained effective control of Pharmasset. The acquisition was completed on January 17, 2012, at which time Pharmasset became a wholly-owned subsidiary of Gilead and was integrated into our operations. As we do not track earnings results by product candidate or therapeutic area, we do not maintain separate earnings results for the acquired Pharmasset business.

The following table summarizes the components of the cash paid to acquire Pharmasset (in thousands):



Total consideration transferred	$	10,858,372
Stock-based compensation expense	193,937
Total cash paid	$	11,052,309

The $11.05 billion cash payment consisted of a $10.38 billion cash payment to the outstanding common stockholders as well as a $668.3 million cash payment to option holders under the Pharmasset stock option plans. The $10.38 billion cash payment to the outstanding common stockholders and $474.3 million of the cash payment to vested option holders under the Pharmasset stock option plans were accounted for as consideration transferred. The remaining $193.9 million of cash payment was accounted for as stock-based compensation expense resulting from the accelerated vesting of Pharmasset employee options immediately prior to the acquisition.

The following table summarizes the acquisition date fair values of assets acquired and liabilities assumed, and the consideration transferred (in thousands):



Identifiable intangible assets	$	10,738,000
Cash and cash equivalents	106,737
Other assets acquired (liabilities assumed), net	(43,182		)
Total identifiable net assets	10,801,555
Goodwill	56,817
Total consideration transferred	$	10,858,372

Identifiable Intangible Assets

We acquired intangible assets, primarily comprised of the sofosbuvir IPR&D compound, which had an estimated fair value of $10.72 billion as of the date of acquisition. The fair value was determined using a probability-weighted income approach that discounts expected future cash flows to present value. The estimated net cash flows were discounted using a discount rate of 12%, which is based on the estimated weighted-average cost of capital for companies with profiles similar to that of Pharmasset. This rate is comparable to the estimated internal rate of return for the acquisition and represents the rate that market participants would use to value the intangible asset. The projected cash flows were based on key assumptions such as: estimates of revenues and operating profits related to each project considering its stage of development on the acquisition date; the time and resources needed to complete the development and approval of the product candidate; the life of the potential commercialized product and associated risks, including the inherent difficulties and uncertainties in developing a product candidate such as obtaining marketing approval from the FDA and other regulatory agencies; and risks related to the viability of and potential alternative treatments in any future target markets. Intangible assets related to IPR&D projects are considered to be indefinite-lived assets and are not amortized until the completion or abandonment of the associated R&D efforts. In December 2013, following the approval by the FDA and commercialization of sofosbuvir as Sovaldi, we reclassified the $10.72 billion purchased IPR&D project for sofosbuvir from an indefinite-lived to finite-lived intangible asset. We are amortizing this asset over its estimated useful life, utilizing the straight-line method.

Goodwill

The $56.8 million of goodwill represents the excess of the consideration transferred over the fair values of assets acquired and liabilities assumed and is attributable to the synergies expected from combining our R&D operations with Pharmasset's. None of the goodwill is expected to be deductible for income tax purposes.

Stock-Based Compensation Expense

The stock-based compensation expense recognized for the accelerated vesting of employee options immediately prior to the acquisition was reported in our Consolidated Statement of Income as follows (in thousands):



	Year Ended
	December 31, 2012
Research and development expense	$	100,149
Selling, general and administrative expense	93,788
Total stock-based compensation expense	$	193,937

Other Costs

Other costs incurred in connection with the acquisition include (in thousands):



	Year Ended December 31,
	2012		2011
Transaction costs (e.g. investment advisory, legal and accounting fees)	$	10,635	$	28,461
Bridge financing costs	7,333		23,817
Restructuring costs	15,125		—
Total other costs	$	33,093	$	52,278

The following table summarizes these costs by the line item in the Consolidated Statement of Income in which these costs were recognized (in thousands):



	Year Ended December 31,
	2012		2011
Research and development expense	$	7,906	$	—
Selling, general and administrative expense	17,854		28,461
Interest expense	7,333		23,817
Total other costs	$	33,093	$	52,278

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 and working capital decreased significantly in 2012 compared to 2011 as we completed our acquisition of Pharmasset in January 2012. The following table summarizes our cash, cash equivalents and marketable securities, working capital and cash flow activities as of the end of, and for each of, the periods presented:



(In thousands)	2013			2012			2011
As of December 31:
Cash, cash equivalents and marketable securities	$	2,570,590		$	2,582,086		$	9,963,972
Working capital ⁽¹⁾	$	948,332		$	1,918,450		$	11,431,584
Year Ended December 31:
Cash provided by (used in):
Operating activities	$	3,104,988		$	3,194,716		$	3,639,010
Investing activities	$	(254,355	)	$	(11,846,054	)	$	3,589,845
Financing activities	$	(2,543,941	)	$	563,346		$	1,763,569


⁽¹⁾	Certain prior period amounts have been reclassified to conform to the current presentation.

Cash, Cash Equivalents and Marketable Securities

Cash, cash equivalents and marketable securities remained relatively flat at $2.57 billion at December 31, 2013, when compared to $2.58 billion at December 31, 2012. During 2013, we generated $3.10 billion in operating cash flows, paid $1.04 billion for the warrants related to our May 2013 Notes that settled in August 2013, repaid $1.67 billion in debt net of proceeds from convertible note hedges and utilized $378.6 million for the acquisition of YM, net of cash acquired.

Cash, cash equivalents and marketable securities totaled $2.58 billion at December 31, 2012, a decrease of $7.38 billion or 74% from December 31, 2011 primarily due to our acquisition of Pharmasset for $11.05 billion in January 2012.

Of the total cash, cash equivalents and marketable securities at December 31, 2013, approximately $1.55 billion was generated from operations in foreign jurisdictions and is intended for use in our foreign operations. We do not rely on unrepatriated earnings as a source of funds for our domestic business as we expect to have sufficient cash flow and borrowing capacity in the United States to fund our domestic operational and strategic needs.

Working Capital

Working capital was $948.3 million at December 31, 2013. The decrease of $970.1 million from working capital as of December 31, 2012 was due to an increase in the current portion of long-term debt and other accrued liabilities, partially offset by increases in accounts receivable, inventories and cash and cash equivalents.

Working capital was $1.92 billion at December 31, 2012. The decrease of $9.51 billion from working capital as of December 31, 2011 was primarily attributable to $11.05 billion in cash used for the Pharmasset acquisition and an increase in short-term debt of $1.17 billion related to the current portion of the bank debt issued to finance the Pharmasset acquisition and the current portion of our May 2013 Notes.

Cash Provided by Operating Activities

Cash provided by operating activities of $3.10 billion in 2013 primarily related to net income of $3.06 billion, adjusted for non-cash items such as $344.7 million of depreciation and amortization expenses and $252.0 million of stock-based compensation expenses. This was partially offset by $562.7 million of net cash outflow related to changes in operating assets and liabilities. In February 2014, we collected approximately $250.0 million in past due accounts receivable from customers based in Spain.

Cash provided by operating activities of $3.19 billion in 2012 primarily related to net income of $2.57 billion, adjusted for non-cash items such as $278.2 million of depreciation and amortization expenses, $208.7 million of stock-based compensation expenses, $107.6 million of net cash inflow related to changes in operating assets and liabilities and $112.6 million of tax benefits from employee stock plans.

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, $211.9 million of net cash inflow related to changes in operating assets and liabilities and $192.4 million of stock-based compensation expenses.

Cash Provided by (Used in) Investing Activities

Cash used in investing activities in 2013 was $254.4 million, consisting primarily of $378.6 million used in our acquisition of YM, net of cash acquired and $190.8 million of capital expenditures primarily related to construction in progress associated with new facilities at our headquarters to support the ongoing growth of our business. This was partially offset by $315.1 million of net proceeds from sales of marketable securities.

Cash used in investing activities in 2012 was $11.85 billion, consisting primarily of $10.75 billion used for our acquisition of Pharmasset, net of the stock-based compensation expense and cash acquired, $672.4 million of net purchases of marketable securities and $397.0 million of capital expenditures, related primarily to the purchase of an office building for $180.0 million and a $155.7 million increase in construction in progress associated with new facilities at our headquarters to support the ongoing growth of our business.

Cash provided by investing activities in 2011 was $3.59 billion, consisting of $4.31 billion of net proceeds 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 Biosciences, Inc. and Calistoga Pharmaceuticals, Inc. and $131.9 million of capital expenditures.

Cash Provided by (Used in) Financing Activities

Cash used in financing activities in 2013 was $2.54 billion, consisting primarily of $4.44 billion used to repay debt financing which includes the maturity of our May 2013 Notes and conversions of our May 2014 Notes and May 2016 Notes, $1.04 billion for the warrants related to our May 2013 Notes that settled in August 2013 and $582.4 million used to repurchase common stock under our stock repurchase program. This cash outflow was partially offset by proceeds of $2.77 billion related to our convertible note hedges.

Cash provided by financing activities in 2012 was $563.3 million, driven primarily by net proceeds of $2.14 billion from the issuance of bank debt in conjunction with the Pharmasset acquisition, proceeds of $466.3 million from issuances of common stock under our employee stock plans and $213.9 million from proceeds received related to our convertible note hedges. The cash proceeds were partially offset by the $1.84 billion used to repay debt financing during the year and $667.0 million used to repurchase common stock under our stock repurchase programs.

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 and $650.0 million used to repay our convertible senior notes due in May 2011.

Debt and Credit Facility

Bank Debt

In January 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 $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.

In 2012, we fully repaid the $1.40 billion in outstanding debt under the Term Loan Credit Agreement and the Short-Term Revolving Credit Agreement, at which time both agreements terminated. In 2013, we repaid $150.0 million under the Five-Year Revolving Credit Agreement.

The Five-Year Revolving Credit Agreement contains customary representations, warranties, affirmative, negative and financial maintenance covenants and events of default. The loan bears 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 credit agreement. We may reduce the commitments and may prepay the loan in whole or in part at any time without premium or penalty. We are required to comply with certain covenants under the credit agreement and note indentures and as of December 31, 2013, we were in compliance with all such covenants.

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. As of December 31, 2013, we had $4.7 million in letters of credit outstanding under the Five-Year Revolving Credit Agreement. The Five-Year Revolving Credit Agreement will terminate and all amounts owed under the agreement shall be due and payable in January 2017.

Maturity of May 2013 Convertible Senior Notes

In 2013, a portion of the May 2013 Notes was converted and on May 1, 2013, the remainder of the notes matured. We repaid an aggregate principal balance of $426.3 million. We also paid $714.0 million in cash related to the conversion spread of the notes, which represents the conversion value in excess of the principal amount, and received $714.0 million in cash from the convertible note hedges related to these notes. The warrants related to the May 2013 Notes expired in August 2013. We paid $1.04 billion to settle the warrants as the average market price of our common stock exceeded the warrants' exercise price.

Convertible Senior Notes and Senior Unsecured Notes

In 2013, a portion of our May 2014 Notes and May 2016 Notes was converted and we repaid $1.09 billion of the principal balance, primarily comprised of May 2014 Notes. We also paid $2.06 billion in cash related to the conversion spread on these notes, which represents the conversion value in excess of the principal amount, and received $2.06 billion in cash from our convertible note hedges related to these notes.

In 2014, our May 2014 Notes will mature and we will settle the related warrants. As our stock price currently exceeds the conversion and warrants’ exercise prices, we expect based on the stock price as of the filing of this form, to pay approximately $3.10 to $3.40 billion to settle the aggregate principal of our May 2014 Notes and the related warrants.

The following is a summary of our borrowings under various financing arrangements (in thousands, except percentages):



				Interest	December 31,
Type of Borrowing	Description	Issue Date	Due Date	Rate	2013		2012
Convertible Senior	May 2013 Notes	April 2006	May 2013	0.625%	$	—	$	419,433
Convertible Senior	May 2014 Notes	July 2010	May 2014	1.00%	234,217		1,210,213
Convertible Senior	May 2016 Notes	July 2010	May 2016	1.625%	1,113,043		1,157,692
Senior Unsecured	April 2021 Notes	March 2011	April 2021	4.50%	993,781		992,923
Senior Unsecured	December 2014 Notes	December 2011	December 2014	2.40%	749,710		749,394
Senior Unsecured	December 2016 Notes	December 2011	December 2016	3.05%	699,326		699,095
Senior Unsecured	December 2021 Notes	December 2011	December 2021	4.40%	1,247,716		1,247,428
Senior Unsecured	December 2041 Notes	December 2011	December 2041	5.65%	997,885		997,810
Credit Facility	Five-Year Revolver	January 2012	January 2017	Variable	600,000		750,000
Total debt, net					6,635,678		8,223,988
Less current portion					2,696,970		1,169,433
Total long-term debt, net					$	3,938,708	$	7,054,555

We believe our existing capital resources, supplemented by cash flows generated from our operations, will be adequate to satisfy our capital needs for the foreseeable future. During 2014, we will consider financing opportunities to better position us for further growth. The amount and terms of any potential financing opportunities, as well as other factors, could affect our liquidity and financial condition. 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;


•	costs associated with the settlement and conversion of our convertible senior notes and related warrants;


•	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 guarantee that it will be available to us on favorable terms, if at all.

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, allowance for doubtful accounts, valuation of intangible assets and contingent consideration liabilities resulting from business combinations and our tax provision. 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. Estimates are assessed each period and updated to reflect current information such as actual experience.

Accrued Government Rebates and Allowance for Government Chargebacks

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 if invoiced directly, or through charge-backs from our wholesalers. 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. 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. Our estimate of government rebates that will be invoiced directly to us are recorded in accrued government rebates on our Consolidated Balance Sheets. Our estimate of government rebates that will be charged back through our wholesalers are recorded as allowances against accounts receivable. Our cons