8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D. C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 21, 2005

ONYX PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of incorporation)

0-28298
(Commission File No.) 94-3154463
(IRS Employer Identification No.)

2100 Powell Street
Emeryville, California 94608
(Address of principal executive offices and zip code)

Registrant’s telephone number, including area code: (510) 957-6500

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 8.01 OTHER EVENTS

     On March 21, 2005, Onyx Pharmaceuticals, Inc., or Onyx, and Bayer Pharmaceuticals Corporation, or Bayer, announced that an independent data monitoring committee, or DMC, has reviewed the safety and efficacy data from the companies’ pivotal Phase III trial in patients with advanced kidney cancer. Based on its analysis, the DMC has concluded that the trial met its surrogate endpoint — resulting in statistically significant longer progression-free survival in those patients administered BAY 43-9006 versus those patients administered placebo. As a result, Bayer and Onyx plan to prepare a New Drug Application for possible accelerated approval of BAY 43-9006 in the United States. As previously agreed with the U.S. Food and Drug Administration, the two companies will continue the Phase III study as originally planned to its primary endpoint of overall survival. The press release dated March 21, 2005, titled “BAY 43-9006 Shown to Delay Disease Progression in Phase III Study in Advanced Kidney Cancer Patients — Study met surrogate endpoint,” is attached hereto as Exhibit 99.1 and is incorporated by reference herein.

     Neither the filing of any press release as an exhibit to this Current Report on Form 8-K nor the inclusion in that press release of a reference to Onyx’s Internet address or Bayer’s Internet address shall, under any circumstances, be deemed to incorporate the information available at such Internet addresses into this Current Report on Form 8-K. The information available at such Internet addresses is not part of this Current Report on Form 8-K or any other report filed by Onyx with the Securities and Exchange Commission.

     This Current Report and exhibit incorporated herein contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities and Exchange Act, as amended, regarding the timing, progress and results of the clinical development, regulatory processes and commercialization efforts of BAY 43-9006. The forward-looking statements involve risks and uncertainties that could cause actual results to differ materially from those referred to in the forward-looking statements. These risks include, but are not limited to, those associated with the timeline for clinical activity, results of pending or future clinical trials, changes in the status of Onyx’s collaborative relationships and Onyx’s expectations or beliefs of the commercial potential of BAY 43-9006. More information about Onyx Pharmaceuticals and these and other risks related to Onyx is detailed in Onyx’s most recent annual report on Form 10-K for the fiscal year ended December 31, 2004 as filed with the U.S. Securities and Exchange Commission. Onyx cannot guarantee any future results, levels of achievement or performance. Onyx does not undertake an obligation to update forward-looking statements.

ITEM 9.01 FINANCIAL STATEMENTS AND EXHIBITS

(c) Exhibits

Exhibit Number	Description
99.1	Press Release titled “BAY 43-9006 Shown to Delay Disease Progression in Phase III Study in Advanced Kidney Cancer Patients — Study met surrogate endpoint” dated March 21, 2005.

SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

ONYX PHARMACEUTICALS, INC. Dated: March 21, 2005
By:	/s/ Marilyn E. Wortzman
	Marilyn E. Wortzman
	Vice President, Finance and Administration

EXHIBIT INDEX

Number	Description
99.1	Press Release titled “BAY 43-9006 Shown to Delay Disease Progression in Phase III Study in Advanced Kidney Cancer Patients — Study met surrogate endpoint” dated March 21, 2005.

EX-99.1

Exhibit 99.1

BAY 43-9006 Shown to Delay Disease Progression
in Phase III Study in Advanced Kidney Cancer Patients
Study met surrogate endpoint

West Haven, CT and Emeryville, CA — March 21, 2005 – Bayer Pharmaceuticals Corporation (NYSE: BAY) and Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) today announced that an independent data monitoring committee (DMC) has reviewed the safety and efficacy data from the companies’ pivotal Phase III trial in patients with advanced kidney cancer. Based on its analysis, the DMC has concluded that the trial met its surrogate endpoint — resulting in statistically significant longer progression-free survival in those patients administered BAY 43-9006 versus those patients administered placebo. As a result of this favorable outcome, Bayer and Onyx plan to prepare a New Drug Application for possible accelerated approval in the United States.

As previously agreed with the U.S. Food and Drug Administration (FDA), the two companies will continue the Phase III study as originally planned to its primary endpoint of overall survival. Bayer and Onyx also intend to submit data from the Phase III study for the upcoming American Society of Clinical Oncology meeting, May 13-17, in Orlando, Florida.

Phase III Summary
The multi-national, placebo-controlled Phase III study recently finished enrolling over 800 patients with advanced kidney cancer. The primary endpoint of the study is overall survival, with disease progression, overall response rate, and safety also being assessed. The pivotal trial was initiated in the fourth quarter of 2003 after a Special Protocol Assessment (SPA) was completed by the FDA.

About BAY 43-9006
BAY 43-9006, a novel investigational drug candidate, has demonstrated both anti-proliferative and anti-angiogenic properties – two important anticancer activities. In preclinical models, BAY 43-9006 inhibited tumor cell proliferation by targeting the RAF/MEK/ERK signaling pathway at the level of RAF kinase. BAY 43-9006 also exerted an antiangiogenic effect by targeting the receptor tyrosine kinases VEGFR-2 and PDGFR and their associated signaling cascades. In addition, BAY 43-9006 also inhibited other tyrosine kinases, including FLT-3 and c-KIT.

About Onyx Pharmaceuticals, Inc.
Onyx Pharmaceuticals, Inc. is engaged in the development of novel cancer therapies that target the molecular basis of cancer. With its collaborators, the company is developing small molecule drugs, including BAY 43-9006 with Bayer Pharmaceuticals Corporation. For more information about Onyx’s pipeline and activities, visit the company’s web site at: www.onyx-pharm.com.

BAY 43-9006 SHOWN TO DELAY DISEASE PROGRESSION IN PHASE III STUDY IN ADVANCED KIDNEY CANCER PATIENTS
MARCH 21, 2005
PAGE 2 OF 2

About Bayer Pharmaceuticals Corporation
Bayer Pharmaceuticals Corporation (www.bayerpharma.com) is part of the worldwide operations of Bayer HealthCare AG, a subgroup of Bayer AG.

Bayer HealthCare, with sales of approximately 8.5 billion Euro in 2004, is one of the world’s leading, innovative companies in the health care and medical products industry. The company combines the global activities of the divisions Animal Health, Biological Products, Consumer Care, Diagnostics and Pharmaceuticals. Bayer HealthCare employed 35,300 people worldwide in 2004.

Our aim is to discover and manufacture innovative products that will improve human and animal health worldwide. Our products enhance well-being and quality of life by diagnosing, preventing and treating disease.

Forward Looking Statements
This news release contains forward-looking statements based on current assumptions and forecasts made by Bayer Group management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Bayer’s public reports filed with the Frankfurt Stock Exchange and with the U.S. Securities and Exchange Commission (including its Form 20-F). Bayer assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

This news release also contains “forward-looking statements” of Onyx within the meaning of the federal securities laws. These forward-looking statements include without limitation, statements regarding the timing, progress and results of the clinical development, regulatory processes and commercialization efforts of BAY 43-9006. These statements are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated. Reference should be made to Onyx’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 16, 2005 under the heading “Additional Business Risks” and Onyx’s Quarterly Reports on Form 10-Q for a more detailed description of such factors. Readers are cautioned not to place undue reliance on these forward-looking statements that speak only as of the date of this release. Onyx undertakes no obligation to update publicly any forward-looking statements to reflect new information, events or circumstances after the date of this release except as required by law.

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Media Contacts:

Mark Bennett	Helmut Schaefers
Bayer Pharmaceuticals Corporation	Bayer HealthCare Communications
+1 203-812-2160	+49 214 30 58308
+1 203-314-5556
Julie Wood
Onyx Pharmaceuticals, Inc.
+ 1 510-597-6505