UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

(Rule 14d-100)

TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)

OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 7)

Cambridge Antibody Technology Group plc

(Name of Subject Company (Issuer))

AstraZeneca PLC

AstraZeneca UK Limited

(Names of Filing Persons (Offerors))

Ordinary Shares

American Depositary Shares

(Title of Class of Securities)

Ordinary Shares (GB0001662252)

American Depositary Shares (US1321481079)

(CUSIP Number of Class of Securities)

Graeme Musker

AstraZeneca PLC

15 Stanhope Gate

London W1K 1LN

Tel: 011 44 20 7304 5000

with a copy to

Thomas B. Shropshire, Jr.

Linklaters

One Silk Street

London EC2Y 8HQ

Tel: 011 44 20 7456 2000

(Name, Address, and Telephone Number of Person

Authorized to Receive Notices and Communications on Behalf of Filing Persons)

CALCULATION OF FILING FEE

Check the appropriate boxes below to designate any transactions to which the statement relates:

Check the following box if the filing is a final amendment reporting the results of the tender offer: o

+ Incorporated by reference to the Schedule 13D filed by AstraZeneca PLC dated December 27, 2004.

ITEM 13.     INFORMATION REQUIRED BY SCHEDULE 13E-3.

Item 8. Fairness of the Transaction

This Amendment amends and supplements Item 8 under Item 13 hereof as follows:

Fairness determinations to unaffiliated holders of CAT Securities

In the context of the Offer Document and related materials, any statements about the determination of fairness of the Offer to the holders of CAT Securities by either the AstraZeneca Entities or CAT should be read and understood to relate to a determination of the fairness of the Offer to the unaffiliated holders of CAT Securities (i.e., holders other than the AstraZeneca Entities).

Further information on the fairness determinations by AstraZeneca Entities

In the context of the Offer, the primary focus of AstraZeneca’s financial analysis was on the value of intellectual property rights and other intangible assets of CAT. That fact, when coupled with the fact that neither net book value nor liquidation value were deemed to be material considerations for the AstraZeneca Entities, means that CAT’s “going concern value” was a factor in its fairness determinations and is reflected in the discussions in the paragraph entitled “Offer price” on page 35 of the Offer Document.

AstraZeneca did not request or obtain a fairness opinion from Goldman Sachs International because the financial and operational analyses were conducted by AstraZeneca and it was not considered necessary or market practice in the United Kingdom to obtain such an opinion.

Further information on the fairness determinations by the CAT Board

For the avoidance of doubt, the CAT Board believes the Offer to be substantively and procedurally fair to all unaffiliated holders of CAT Securities.

As stated in paragraph 3 of the Part III of the Offer Document, the CAT Board considered a number of factors in making its fairness determination, including CAT’s current and anticipated business, financial condition, results of operations and prospects, short and medium-term expectations of profitability and related forward-looking issues. Those considerations, when coupled with the fact that neither net book value nor liquidation value were deemed to be material considerations for the CAT Board’s determinations, means that CAT’s “going concern value” was a factor in its fairness determinations.

The CAT Board did not, and does not, consider valuations based on net book value or liquidation value to be generally considered appropriate for companies such as CAT and, as a result, were not considered relevant to the CAT Board’s fairness determination. For example, although the Offer price is 1,320 pence per CAT Share, the net book value per CAT Share, which is disclosed in paragraph 11.13 of Appendix V on page 147 of the Offer Document, was 341 pence, significantly below the Offer price.

The CAT Board did not consider it necessary to retain a separate unaffiliated representative for the non-executive directors on the CAT Board because none of the directors of CAT is an affiliate of AstraZeneca for U.S. federal securities law purposes and, in addition, a majority of CAT’s directors are non-executive directors, all of whom voted to recommend the Offer as stated in paragraph 5 of Part III of the Offer Document. Furthermore, CAT is an English public limited company and, while certain U.S. companies may consider retaining such a representative in connection with state law conflicts of interest provisions, there is no requirement under English company law to do so nor is it usual for an English company to do so in circumstances such as the Offer.

The CAT Board did not believe that the payments to Morgan Stanley had a material impact on the CAT Board’s determination of fairness of the Offer. The CAT Board appointed Morgan Stanley because it wished to retain the advice of financial experts in these matters and was required to obtain competent independent advice in connection with the Offer under the City Code. CAT believes that is customary in the United Kingdom for payments to the financial adviser to be staggered, as was done with Morgan Stanley, and the amounts payable to Morgan Stanley are what may customarily have been expected in these circumstances.

Role of CAT Offer Committee

For the avoidance of doubt, the CAT Offer Committee of the Board was appointed to deal solely with administrative matters related to the execution of the Offer. This committee was not formed to consider the fairness of the Offer and made no such determination.

Item 16. Exhibits

SIGNATURE

      After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

EXHIBIT INDEX