Onyx Pharmaceuticals Completes Enrollment in FOCUS Phase 3 Carfilzomib Trial in Patients with Relapsed and Refractory Multiple Myeloma

Onyx Pharmaceuticals Completes Enrollment in FOCUS Phase 3 Carfilzomib Trial in Patients with Relapsed and Refractory Multiple Myeloma

South San Francisco, CA. — Oct. 15, 2012

Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) today announced that the company completed enrollment in the FOCUS trial, an international Phase 3 clinical trial evaluating single-agent carfilzomib in patients with relapsed and refractory myeloma who have received three or more prior therapies. The FOCUS (CarFilzOmib for AdvanCed Refractory MUltiple Myeloma European Study) trial is designed to support regulatory approvals around the world.

"Completing enrollment for the Phase 3 FOCUS trial is a major milestone in the carfilzomib global development program," said Barbara Klencke, M.D., Senior Vice President of Clinical Development at Onyx Pharmaceuticals. "It brings us one step closer to having carfilzomib available to patients around the world who are in need of new treatment options for advanced myeloma."
Phase 3 Trial Design

The FOCUS trial is evaluating carfilzomib versus best supportive care of low-dose steroids plus optional cyclophosphamide in patients with relapsed and refractory multiple myeloma following treatment with at least three prior therapies. The primary endpoint of the trial is overall survival. Secondary endpoints include progression-free survival, overall response rate, clinical benefit response, duration of response and safety. Patients were randomized to receive carfilzomib (20mg/m2 on days 1 and 2 of cycle 1 only, then 27mg/m2 on days 8, 9, 15, 16 of cycle 1 and all doses in subsequent cycles) or best supportive care.

For more information about this study, please visit www.clinicaltrials.gov.
Important Indication and Safety Information Regarding Kyprolis™ (carfilzomib) for Injection

On July 20, 2012, the U.S. Food and Drug Administration (FDA) granted accelerated approval of Kyprolis™ (carfilzomib) for Injection for the treatment of patients with multiple myeloma who have received at least two prior therapies including bortezomib and an immunomodulatory agent (IMiD), and have demonstrated disease progression on or within 60 days of completion of the last therapy. Approval was based on response rate. Clinical benefit, such as improvement in survival or symptoms, has not been verified.

Safety data have been evaluated in 526 patients with relapsed and/or refractory multiple myeloma who received single-agent Kyprolis. There were 37 deaths in the phase 2 studies, or 7% of patients. The most common causes of death, other than disease progression, were cardiac (5 patients), end-organ failure (4 patients), and infection (4 patients). Important warnings and precautions include cardiac arrest, congestive heart failure, myocardial ischemia; pulmonary hypertension, pulmonary complications, infusion reactions, tumor lysis syndrome, thrombocytopenia, hepatic toxicity and embryo-fetal toxicity.

Death due to cardiac arrest has occurred within a day of Kyprolis administration. Patients with New York Heart Association Class III and IV heart failure, myocardial infarction in the preceding 6 months, and conduction abnormalities uncontrolled by medications were not eligible for the clinical trials. These patients may be at greater risk for cardiac complications.

Pulmonary arterial hypertension (PAH) was reported in 2% of patients treated with Kyprolis and was Grade 3 or greater in less than 1% of patients. Dyspnea was reported in 35% of patients enrolled in clinical trials. Grade 3 dyspnea occurred in 5%; no Grade 4 events, and 1 death (Grade 5) was reported.

Infusion reactions, characterized by a spectrum of systemic symptoms including fever, chills, arthralgia, myalgia, facial flushing, facial edema, vomiting, weakness, shortness of breath, hypotension, syncope, chest tightness, or angina can occur immediately following or up to 24 hours after administration of Kyprolis. Administration of dexamethasone prior to Kyprolis reduces the incidence and severity of reactions. Tumor lysis syndrome (TLS) occurred following Kyprolis administration in < 1% of patients. Patients with multiple myeloma and a high tumor burden should be considered to be at greater risk for TLS.

Thrombocytopenia following Kyprolis administration resulted in a dose reduction in 1% of patients and discontinuation of treatment with Kyprolis in < 1% of patients.

Cases of hepatic failure, including fatal cases, have been reported (< 1%). Kyprolis can cause elevations of serum transaminases and bilirubin.

There are no adequate and well-controlled studies in pregnant women using Kyprolis. Females of reproductive potential should be advised to avoid becoming pregnant while being treated with Kyprolis.

The most common serious adverse reactions were pneumonia, acute renal failure, pyrexia, and congestive heart failure. The most common adverse reactions (incidence of 30% or greater) observed in clinical trials of patients with multiple myeloma were fatigue, anemia, nausea, thrombocytopenia, dyspnea, diarrhea, and pyrexia. Serious adverse reactions were reported in 45% of patients.

Full prescribing information is available at http://www.onyx.com.
About Multiple Myeloma

Multiple myeloma is the second most common hematologic cancer and results from an abnormality of plasma cells, usually in the bone marrow. In the United States, more than 50,000 people are living with multiple myeloma and approximately 20,000 new cases are diagnosed annually.i Worldwide, more than 220,000 people are living with multiple myeloma and approximately 100,000 new cases are diagnosed annually.ii Worldwide, it is estimated that there are approximately 25,000 to 35,000 patients with relapsed and refractory multiple myeloma.
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.
Forward-Looking Statements

This news release contains "forward-looking statements" of Onyx within the meaning of the federal securities laws. These forward-looking statements include, without limitation, statements regarding the progress and results of the clinical development, safety, regulatory processes, commercialization capabilities or efforts or commercial potential of Kyprolis (carfilzomib). These statements are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated, including risks related to the development and commercialization of pharmaceutical products. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Reference should be made to Onyx's Annual Report on Form 10-K for the year ended December 31, 2011, filed with the Securities and Exchange Commission under the heading "Risk Factors" and Onyx's Quarterly Reports on Form 10-Q under the heading "Risk Factors" 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.

i American Cancer Society, Cancer Facts & Figures 2012
ii National Analysts & Kantar Health Market Research