Phase 3 Data on Regorafenib Met Primary Endpoint Showing Significant Improvement in Progression-Free Survival in Patients with GIST

SOUTH SAN FRANCISCO, Calif., June 4, 2012 /PRNewswire/ -- Onyx Pharmaceuticals (Nasdaq: ONXX) today announced data from the Phase 3 GRID (GIST – Regorafenib In Progressive Disease) trial evaluating the investigational drug regorafenib, a Bayer compound, in patients with metastatic and/or unresectable gastrointestinal stromal tumors (GIST) whose disease had progressed despite prior treatment with imatinib and sunitinib. The GRID study met its primary endpoint of progression-free survival (PFS) (HR=0.27, p<0.0001).(1) The median PFS was 4.8 months in the regorafenib arm vs. 0.9 months in the placebo arm.(1) These data will be presented as a late-breaking abstract in an oral abstract session at the 48th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago, IL (USA) (LBA No. 10008).

"GIST continues to represent an area of unmet patient need, given the aggressive nature of the disease and our limited therapeutic options," said George Demetri, MD, Director, Center for Sarcoma and Bone Oncology, Dana-Farber Cancer Institute, and Chair of the Steering Committee for the GRID trial. "These data from the GRID study indicate that regorafenib may be a potential treatment option for patients who have relapsed after standard therapies."

The most common drug-related, treatment-emergent adverse events (occurring in at least 10% of patients during double-blind treatment) included hand-foot skin reaction (56.1% vs.15.2%), hypertension (48.5% vs. 16.7%), diarrhea (40.9% vs.7.6%), fatigue (38.6% vs. 27.3%), oral mucositis (37.9% vs. 9.1%), alopecia (23.5% vs. 3.0%), hoarseness (22.0% vs. 4.5%), anorexia (20.5% vs. 7.6%), rash, maculopapular (18.2% vs. 3.0%), nausea (15.9% vs. 9.1%), constipation (15.2% vs. 7.6%), myalgia (13.6% vs. 9.1%), and voice alteration (11.4% vs. 3.0%) for patients receiving regorafenib as compared to placebo.(1)

Bayer has submitted a New Drug Application to the U.S. Food and Drug Administration (FDA) for the oral multi-kinase inhibitor regorafenib for the treatment of patients with metastatic colorectal cancer (mCRC). Bayer plans to submit a New Drug Application for regorafenib in GIST in the second half of 2012.

About the GRID Trial

GRID was a randomized, double-blind, placebo-controlled, multi-center, cross-over Phase 3 study of regorafenib for the treatment of GIST.(1)  It enrolled 199 patients whose disease had progressed despite prior treatment with imatinib and sunitinib.(1)  Patients were randomized in a 2:1 ratio to receive either regorafenib (160 mg once daily, three weeks on/ one week off) plus BSC or placebo plus BSC to evaluate efficacy and safety.(1) The primary endpoint of this trial was PFS, and secondary endpoints included overall survival, time to progression, disease control rate, tumor response rate, and duration of response.(2)

About Regorafenib

Regorafenib is an investigational oral multi-kinase inhibitor and is currently being investigated in clinical trials for its potential to treat patients with various tumor types.(2)

Regorafenib is an investigational agent and is not approved by the FDA, EMA or other health authorities.

Regorafenib is one of several cancer compounds in Bayer's development pipeline. In 2011, Bayer entered into an agreement with Onyx Pharmaceuticals, Inc., under which Onyx will receive a royalty on any future global net sales of regorafenib in oncology. Bayer and Onyx will jointly promote regorafenib in the U.S.

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.

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 potential expansion of Onyx's product portfolio, the possibility of royalty payments to Onyx from the sale of regorafenib, and the timing, progress and results of clinical development and the regulatory approval process. These statements are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated, including, but not limited to, risks and uncertainties related to: Nexavar being our only approved product; we may never receive marketing approval for Kyprolis (carfilzomib) or regorafenib; competition; failures or delays in our clinical trials or the regulatory process; dependence on our collaborative relationship with Bayer; if approved, we or Bayer, as the case may be, may be unsuccessful in launching, maintaining adequate supply of or obtaining reimbursement for Kyprolis or regorafenib; market acceptance and the rate of adoption of our products; pharmaceutical pricing and reimbursement pressures; serious adverse side effects, if they are associated with Nexavar, regorafenib or Kyprolis; government regulation; possible failure to realize the anticipated benefits of business acquisitions or strategic investments; protection of our intellectual property; the indebtedness incurred through the sale of our 4.0% convertible senior notes due 2016; and product liability risks. 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, as updated by Onyx's subsequent Quarterly Reports on Form 10-Q, under the heading "Risk Factors" for a more detailed description of these and other risks. 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.

References:

1. Demetri, et al. Randomized phase III trial of regorafenib in patients (pts) with metastatic and/or unresectable gastrointestinal stromal tumor (GIST) progressing despite prior treatment with at least imatinib (IM) and sunitinib (SU): GRID trial [Presentation]. 2012 American Society of Clinical Oncology; June 1-5, 2012. Chicago, IL.
2. Bayer Healthcare. A randomized, double-blind, placebo-controlled phase III study of regorafenib plus best supportive care versus placebo plus best supportive care for subjects with metastatic and/or unresectable gastrointestinal stromal tumors (GIST) whose disease has progressed despite prior treatments with at least imatinib and sunitinib [Integrated Clinical Study Protocol]. September 27 2011.

SOURCE Onyx Pharmaceuticals, Inc.