Onyx Pharmaceuticals Presents Interim Results of Phase 1b Carfilzomib Combination Trial

EMERYVILLE, Calif., June 4 /PRNewswire-FirstCall/ -- Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) today announced updated interim results of the Phase 1b dose-escalation trial, known as the 006 study, evaluating carfilzomib in combination with lenalidomide (Revlimid®) and low dose dexamethasone in patients with relapsed and/or refractory myeloma.  These data are being presented today at the 46th American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago by William Bensinger, M.D., Professor of Medicine of the Division of Oncology, Fred Hutchinson Cancer Research Center at the University of Washington School of Medicine.  

The overall response rate in the cohorts of patients receiving full doses of the combination was 75 percent in 48 evaluable patients.  Median duration of response has not yet been reached.  No dose-limiting toxicities were observed, and the maximum tolerated dose was not reached.  The maximum per-protocol doses of 27mg/m2 carfilzomib, 25mg lenalidomide, and low dose (40mg) dexamethasone were safely administered.  Overall response is measured as a partial response or greater.(i)

"Nearly all patients with multiple myeloma who receive initial treatment will eventually relapse and require further therapy," said Dr. Bensinger.  "Although new agents have been developed over the past several years, we require additional treatment options that improve progression-free survival and extend overall response rates with a tolerability profile that is mild and manageable.  The interim results from this Phase 1b study show an encouraging efficacy profile in this heavily pretreated group of patients with myeloma, with no overlapping toxicities with the treatment triplet.  We look forward to further study of this important carfilzomib-based combination regimen in the upcoming international Phase 3 trial."

Additional Phase 1b Trial Results

The study was designed to evaluate the safety, maximum tolerated or maximum per-protocol doses, and efficacy of carfilzomib in combination with lenalidomide and low-dose dexamethasone.  Forty patients were enrolled in the dose-escalation portion of this study (cohorts 1-6).  Doses were escalated from 15mg/m2 carfilzomib and 10mg lenalidomide to the maximum per-protocol doses of 27 mg/m2 carfilzomib and 25mg lenalidomide.  A total of fifty-two patients received the maximum per-protocol doses, including eight patients in cohort 6 and forty-four patients in the expansion cohort.  All patients enrolled in the study received 40mg low dose dexamethasone.

Of the 84 patients in the trial, 79 percent had received more than two prior treatment regimens for myeloma with 74 percent of the patients having received prior bortezomib, 87 percent prior immunomodulatory drug therapy (67 percent prior lenalidomide and 44 percent prior thalidomide), and 98 percent prior steroids.

Side effects were clinically manageable and generally consistent with those typically seen with the agents that were combined with carfilzomib.  Grade 3/4 adverse events included neutropenia (23 percent), thrombocytopenia (18 percent), anemia (12 percent), and hyperglycemia (5 percent).  The triple combination regimen was well tolerated and prolonged administration (14-23 months) without interruption was possible, allowing for durable disease control. Initial responses typically occurred within the first cycle, with many patients showing even greater improvement over the subsequent months while remaining on the initial doses of each agent.

"Based on promising results from this trial, we are planning to enroll patients in a Phase 3 trial to further evaluate this three-drug combination therapy in patients with relapsed myeloma," said Michael Kauffman, M.D., Ph.D., Chief Medical Officer at Onyx.  "Later this year, we expect to submit a U.S. New Drug Application filing for carfilzomib as a single agent for relapsed/refractory myeloma under the accelerated approval mechanism, pending the top-line results from our Phase 2b trial, known as the 003-A1 study."  

About the Carfilzomib Development Program

Carfilzomib is a selective, next-generation proteasome inhibitor that is being investigated in a broad clinical trial program in multiple myeloma.

The pivotal Phase 2b monotherapy study, also known as 003-A1, enrolled patients with relapsed/refractory multiple myeloma.  Top-line results, expected mid-year, may support the filing of a U.S. New Drug Application (NDA) by year-end 2010.  

A European Phase 3 clinical trial of carfilzomib is planned in relapsed/refractory myeloma and is designed to support a registrational filing with the EMA. Carfilzomib is also being evaluated in advanced solid tumors.

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 U.S., more than 50,000 people are living with multiple myeloma and approximately 20,000 new cases are diagnosed annually.(ii)  According to estimates by the European Network of Cancer Registries, there are 21,420 new cases of multiple myeloma in Europe each year and around 15,000 deaths from this illness. It is estimated that 60,000 people in Europe are currently living with this disease.

Worldwide, more than 180,000 people are living with MM and approximately 86,000 new cases are diagnosed annually.(iii)

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, a targeted alpha-folate inhibitor, and ONX 0912, an oral proteasome inhibitor, are 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.

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 efforts or commercial potential of 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, 2009, filed with the Securities and Exchange Commission under the heading "Risk Factors" 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.  

(i)   Partial response is defined by > 50% reduction of serum M-protein and reduction in 24 hour urinary M-protein by > 90% or to < 200 mg per 24 hours, International Uniform Response Criteria for Multiple Myeloma Published in Leukemia (2006) 20:1467-1473) with an Erratum in Leukemia (2007)21:1134-1135

(ii)  National Cancer Institute, Surveillance Epidemiology and End Results, 2007 Facts and Figures

(iii) International Agency for Research on Cancer, GLOBOCAN 2002 database

SOURCE Onyx Pharmaceuticals, Inc.