defa14a

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934
(Amendment No.__)


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Filed by a Party other than the Registrant		o

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o    Preliminary Proxy Statement
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o    Definitive Proxy Statement
þ    Definitive Additional Materials
o    Soliciting Material Pursuant to § 240.14a-12

ONYX PHARMACEUTICALS, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if Other Than the Registrant)

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ONYX PHARMACEUTICALS, INC.

** IMPORTANT NOTICE **

Regarding the Availability of Proxy Materials

You are receiving this communication because you hold shares in the above company, and the materials you should review before you cast your vote are now available.

This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting.

2100 POWELL STREET
EMERYVILLE, CA 94608

Shareholder Meeting to be held on 5/26/09

Proxy Materials Available

•      Notice and Proxy Statement
•     Annual Report
•     Form 10-K

PROXY MATERIALS - VIEW OR RECEIVE

You can choose to view the materials online or receive a paper or e-mail copy. There is NO charge for requesting a copy. Requests, instructions and other inquiries will NOT be forwarded to your investment advisor.

To facilitate timely delivery please make the request as instructed below on or before 5/12/09.

HOW TO VIEW MATERIALS VIA THE INTERNET

Have the 12 Digit Control Number available and visit: www.proxyvote.com

HOW TO REQUEST A COPY OF MATERIALS


1) BY INTERNET		- www.proxyvote.com
2) BY TELEPHONE		- 1-800-579-1639
3) BY E-MAIL*		- sendmaterial@proxyvote.com

*If requesting materials by e-mail, please send a blank e-mail with the 12 Digit Control Number (located on the following page) in the subject line.

See the Reverse Side for Meeting Information and Instructions on How to Vote

Meeting Information


Meeting Type:		Annual
Meeting Date:		5/26/09
Meeting Time:		10:00 A.M. local time
For holders as of:		3/30/09

Meeting Location:

Hilton Garden Inn
1800 Powell Street
Emeryville, CA 94608

How To Vote


		Vote In Person

		Many shareholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the Meeting, you will need to request a ballot to vote these shares.


		Vote By Internet

		To vote *now* by Internet, go to WWW.PROXYVOTE.COM. Use the Internet to transmit your voting instructions and for electronic delivery of information up until 11:59 P.M. Eastern Time, May 25, 2009. Have your notice in hand when you access the web site and follow the instructions.


				Voting items



		The Board of Directors recommends a vote FOR items 1, 2 and 3.

		1.		ELECTION OF DIRECTORS

				Nominees:

				1a. Paul Goddard, Ph.D.

				1b. Antonio J. Grillo-López, M.D.

				1c. Wendell Wierenga, Ph.D.

		2.		TO APPROVE AN AMENDMENT TO THE COMPANY’S 2005 EQUITY INCENTIVE PLAN TO, AMONG OTHER THINGS, INCREASE THE AGGREGATE NUMBER OF SHARES OF COMMON STOCK AUTHORIZED FOR ISSUANCE UNDER THE PLAN BY 2,000,000 SHARES.

		3.		TO RATIFY THE SELECTION BY THE AUDIT COMMITTEE OF THE BOARD OF DIRECTORS OF ERNST & YOUNG LLP AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THE FISCAL YEAR ENDING DECEMBER 31, 2009.