AstraZeneca PLC — Director's Dealing 2012

May 1, 2012

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Ardea Biosciences, Inc./DE (RDEA)
CIK: 0001103390
Period of Report: 2012-04-21

Reporting Person: ASTRAZENECA PLC (10% Owner)

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	0	Indirect

Footnotes

F1: This form is a joint filing by (i) Zeneca Inc. ("Zeneca"); (ii) Zeneca Holdings Inc.; (iii) AstraZeneca Holdings BV; (iv) AstraZeneca Treasury Limited; (v) AstraZeneca UK Limited; (vi) AstraZeneca Intermediate Holdings Limited; and (vii) AstraZeneca PLC (all entities listed in (i) through (vii), the "AZ Entities"). AstraZeneca PLC is the direct parent of AstraZeneca Intermediate Holdings Limited and the indirect parent of the entities listed in (i) through (v). The address of each of the AZ Entities is listed in Exhibit 99.1.

F2: As an inducement to Zeneca entering into the Agreement and Plan of Merger, dated as of April 21, 2012 (the "Merger Agreement"), by and among Zeneca, QAM Corp. and Ardea Biosciences, Inc. ("Ardea"), and in consideration thereof, Zeneca and certain directors and executive officers of Ardea and certain of their respective affiliates (the "Key Stockholders") entered into Voting Agreements, dated as of April 21, 2012 (the "Voting Agreements"), (continued in Footnote 3)

F3: pursuant to which the Key Stockholders have agreed to vote, or cause to be voted, all shares of Ardea common stock ("Shares") beneficially owned by them (i) in favor of the adoption of the Merger Agreement and, without limitation of the preceding language, the approval of certain proposals to adjourn or postpone any meeting of Ardea stockholders to a later date if there are not sufficient votes for adoption of the Merger Agreement on the date on which such meeting is held, and (ii) against (a) any proposal made in opposition to, or in competition with, the transactions contemplated by the Merger Agreement and (b) any acquisition transaction and any other action or agreement that is intended to or would reasonably be expected to impede, prevent, delay or adversely affect the transactions contemplated by the Merger Agreement, in each case, on the terms and subject to the conditions set forth in the Voting Agreements.

F4: The AZ Entities, by reason of the execution and delivery by Zeneca of the Voting Agreements, may be deemed to have shared voting power with the Key Stockholders with respect to (and therefore beneficially own within the meaning of Rule 13d-3 under the Securities Exchange Act of 1934 (the "Exchange Act")) an aggregate of 10,886,949 Shares (representing approximately 29.6% of Ardea's issued and outstanding Shares (assuming 36,768,915 Shares issued and outstanding as of April 18, 2012, as represented by Ardea in the Merger Agreement)) and shared dispositive power with the Key Stockholders with respect to an aggregate of 12,181,075 Shares (comprised of (i) 10,886,949 issued and outstanding Shares and (ii) 1,294,126 Shares issuable upon exercise of outstanding options and warrants that are subject to the Voting Agreements.

F5: None of the AZ Entities have any pecuniary interest in the Shares and therefore do not have beneficial ownership of any Shares within the meaning of Rule 16a-1(a)(2) of the Exchange Act.

F6: Neither the filing of this Form 3 nor any of its contents shall be deemed to constitute an admission by any AZ Entity or any other person that he, she or it is the beneficial owner of any of the Shares referred to herein for purposes of Section 13(d) or Section 16 of the Exchange Act, or for any other purpose, and such beneficial ownership is expressly disclaimed.