2009 Press Releases

Onyx Pharmaceuticals to Host American Society of Hematology (ASH) Investor Teleconference

Emeryville, CA. — Dec. 04, 2009

Onyx Pharmaceuticals, Inc. (NASDAQ: ONXX) today announced that it will host an investor teleconference and webcast. Principal investigators will discuss the data presentations surrounding carfilzomib in relapsed and/or refractory multiple myeloma, as featured at the 51st American Society of Hematology (ASH) Annual Meeting.

The teleconference will begin at 9:00 a.m. CT/10:00 a.m. ET on Monday, December 7, 2009. The live webcast will be available at:

http://www.onyx-pharm.com/view.cfm/32/Event-Calendar

or by dialing 847-413-3362 and using the passcode 25914947. A replay of the presentation will be available on the Onyx website or by dialing 630-652-3044 and using the passcode 25914947 later in the day. The replay will be available on the Onyx website through January 7, 2010.

About Onyx Pharmaceuticals, Inc.
Onyx Pharmaceuticals, Inc. is a biopharmaceutical company committed to improving the lives of people with cancer. The company, in collaboration with Bayer HealthCare Pharmaceuticals, Inc., is developing and marketing Nexavar® (sorafenib) tablets a small molecule drug that is currently approved for the treatment of liver cancer and advanced kidney cancer. Additionally, Nexavar is being investigated in several ongoing trials in a variety of tumor types. Beyond Nexavar, Onyx has established a development pipeline of anticancer compounds at various stages of clinical testing, including carfilzomib, a next-generation proteasome inhibitor, that is currently being evaluated in multiple clinical trials for the treatment of patients with relapsed or relapsed/refractory multiple myeloma and solid tumors. ONX 0801 is a targeted alpha-folate inhibitor currently in Phase 1 testing. For more information about Onyx, visit the company's website at www.onyx-pharm.com.

Nexavar® (sorafenib) tablets is a registered trademark of Bayer HealthCare Pharmaceuticals.