Onyx Pharmaceuticals Announces Conference Call to Discuss Phase 3 DECISION Data at 2013 ASCO Annual Meeting

  Onyx Pharmaceuticals, Inc. (NASDAQ: ONXX) today announced that it will hold a conference call to discuss data presented at an ASCO plenary session from the DECISION study, a Phase 3 trial investigating the use of Nexavar® (sorafenib) tablets in patients with locally advanced or metastatic radioactive iodine-refractory (RAI) differentiated thyroid cancer. The call will feature the principal investigator, Marcia Brose, M.D., Ph.D., Assistant Professor in the Abramson Cancer Center and the Perelman School of Medicine at the University of Pennsylvania, and will include members of Onyx's management.

Date: Monday, June 3, 2013 Time: 10:15 - 11:00 a.m. Central Time

To access a live audio webcast of the conference call, log onto the company's website at: http://www.onyx.com/investors/event-calendar

To access the live conference call, dial 847-585-4405 and use the passcode 34979134 #. A replay of the call will be available on the Onyx website or by dialing 630-652-3042 and using the passcode 34979134 # approximately one hour after the conference call concludes through June 17, 2013.

About Nexavar® (sorafenib) Tablets Nexavar is approved in the U.S. for the treatment of patients with unresectable hepatocellular carcinoma and for the treatment of patients with advanced renal cell carcinoma. Nexavar is thought to inhibit both the tumor cell and tumor vasculature. In in vitro studies, Nexavar has been shown to inhibit multiple kinases thought to be involved in both cell proliferation (growth) and angiogenesis (blood supply) - two important processes that enable cancer growth. These kinases include Raf kinase, VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-B, KIT, FLT-3 and RET.

Nexavar is currently approved in more than 100 countries. Nexavar is also being evaluated by Bayer and Onyx, international study groups, government agencies and individual investigators in a range of cancers.

Important Safety Considerations For Nexavar® (sorafenib) Tablets Nexavar in combination with carboplatin and paclitaxel is contraindicated in patients with squamous cell lung cancer.

Cardiac ischemia and/or myocardial infarction may occur. Temporary or permanent discontinuation of Nexavar should be considered in patients who develop cardiac ischemia and/or myocardial infarction.

An increased risk of bleeding may occur following Nexavar administration. If bleeding necessitates medical intervention, consider permanent discontinuation of Nexavar.

Hypertension may occur early in the course of treatment. Monitor blood pressure weekly during the first 6 weeks and periodically thereafter and treat, if required.

Hand-foot skin reaction and rash are common and management may include topical therapies for symptomatic relief. In cases of any severe or persistent adverse reactions, temporary treatment interruption, dose modification, or permanent discontinuation of Nexavar should be considered. Nexavar should be discontinued if Stevens-Johnson Syndrome or toxic epidermal necrolysis are suspected as these may be life threatening.

Gastrointestinal perforation was an uncommon adverse reaction and has been reported in less than 1% of patients taking Nexavar. Discontinue Nexavar in the event of a gastrointestinal perforation.

Patients taking concomitant warfarin should be monitored regularly for changes in prothrombin time (PT), International Normalized Ratio (INR) or clinical bleeding episodes.

Temporary interruption of Nexavar therapy is recommended in patients undergoing major surgical procedures.

Nexavar in combination with gemcitabine/cisplatin is not recommended in patients with squamous cell lung cancer. The safety and effectiveness of Nexavar has not been established in patients with non-small cell lung cancer.

Nexavar can prolong the QT/QTc interval and increase the risk for ventricular arrhythmias. Avoid use in patients with congenital long QT syndrome and monitor patients with congestive heart failure, bradyarrhythmias, drugs known to prolong the QT interval, and electrolyte abnormalities.

Drug-induced hepatitis with Nexavar may result in hepatic failure and death. Liver function tests should be monitored regularly and in cases of increased transaminases without alternative explanation Nexavar should be discontinued.

Nexavar may cause fetal harm when administered to a pregnant woman. Women of childbearing potential should be advised to avoid becoming pregnant while on Nexavar and female patients should also be advised against breastfeeding while receiving Nexavar.

Elevations in serum lipase and reductions in serum phosphate of unknown etiology have been associated with Nexavar.

Avoid concomitant use of strong CYP3A4 inducers, when possible, because inducers can decrease the systemic exposure of Nexavar. Nexavar exposure decreases when coadministered with oral neomycin. Effects of other antibiotics on Nexavar pharmacokinetics have not been studied.

Most common adverse reactions reported for Nexavar-treated patients vs. placebo-treated patients in unresectable HCC, respectively, were: diarrhea (55% vs. 25%), fatigue (46% vs. 45%), abdominal pain (31% vs. 26%), weight loss (30% vs. 10%), anorexia (29% vs. 18%), nausea (24% vs. 20%), and hand-foot skin reaction (21% vs. 3%). Grade 3/4 adverse reactions were 45% vs. 32%.

Most common adverse reactions reported for Nexavar-treated patients vs. placebo-treated patients in advanced RCC, respectively, were: diarrhea (43% vs. 13%), rash/desquamation (40% vs. 16%), fatigue (37% vs. 28%), hand-foot skin reaction (30% vs. 7%), alopecia (27% vs. 3%), and nausea (23% vs. 19%). Grade 3/4 adverse reactions were 38% vs. 28%.

For information about Nexavar including U.S. Nexavar prescribing information, visit www.nexavar-us.com or call 1.866.NEXAVAR (1.866.639.2827).

About Onyx Pharmaceuticals, Inc. Based in South San Francisco, California, Onyx Pharmaceuticals, Inc. is a global biopharmaceutical company engaged in the development and commercialization of innovative therapies for improving the lives of people with cancer. The company is focused on developing novel medicines that target key molecular pathways. For more information about Onyx, visit the company's website at www.onyx.com. Onyx Pharmaceuticals is on Twitter. Sign up to follow our Twitter feed @OnyxPharm at http://twitter.com/OnyxPharm.

Contact: Nicole Keith 650-266-2123