Bayer and Onyx Begin Enrollment in STORM Trial Studying Nexavar as Adjuvant Therapy for Patients with Liver Cancer

Wayne, N.J. and Emeryville, Calif., August 21, 2008 -- Bayer HealthCare Pharmaceuticals, Inc. and Onyx Pharmaceuticals, Inc. today announced the companies have begun enrolling patients in the STORM Sorafenib as Adjuvant Treatment in the Prevention of Recurrence of Hepatocellular Carcinoma trial. The randomized, double-blind, placebo-controlled Phase 3 study is evaluating Nexavar (sorafenib) tablets as adjuvant treatment, which is treatment following surgery or local radiation, for patients with hepatocellular carcinoma (HCC), or primary liver cancer.

"Nexavar is the only systemic therapy with proven efficacy and tolerability in HCC across multiple patient populations," said Dimitris Voliotis, MD, vice president, Nexavar Clinical Development, Bayer HealthCare Pharmaceuticals. "Liver cancer is the third largest global cancer killer worldwide and there is a significant need for new therapies that can be used at all stages in the course of the disease to delay disease progression and prolong life."

In addition, the U.S. Food and Drug Administration (FDA) has completed a Special Protocol Assessment (SPA) for the STORM trial. An SPA is a written agreement on the design and size of a clinical trial intended to form the basis for a new drug application.

Phase 3 Trial Design

The international multicenter study is expected to enroll approximately 1,100 patients and will include patients who have received surgical resection or local ablation. The study will look at whether providing oral Nexavar in the adjuvant setting delays the time to recurrence and increases overall survival. The primary endpoint of the study is recurrence free survival. Secondary endpoints include overall survival, time to recurrence, patient-reported outcomes, plasma biomarkers, safety and tolerability.

The study is enrolling patients with all HCC histologies. Patients will be randomized to receive 400 mg of Nexavar twice daily or matching placebo for up to four years. The study will be conducted at more than 200 sites in North America, South America, Europe and the Asia-Pacific region, including Japan. For information about enrolling in the study, please visit www.clinicaltrials.gov.

Hepatocellular carcinoma is the most common form of liver cancer and is responsible for about 90 percent of the primary malignant liver tumors in adults. Liver cancer is the sixth most common cancer in the world and the third leading cause of cancer-related deaths globally. More than 600,000 cases of liver cancer are diagnosed worldwide each year (more than 400,000 in China, South Korea, Japan and Taiwan, 54,000 in the European Union, and 15,000 in the United States) and the incidence is increasing. In 2002, approximately 600,000 people died of liver cancer including approximately 370,000 in China, South Korea and Japan, 57,000 in the European Union, and 13,000 in the United States.(1,2)

Currently there are no adjuvant treatments with proven benefit in HCC and half of the patients who have undergone surgical resection or local ablation will see their tumors return within three years and 70 percent will see their tumors return within five years.(3)

Nexavar's Differentiated Mechanism

Nexavar targets both the tumor cell and tumor vasculature. In preclinical studies, Nexavar has been shown to target members of two classes of kinases known to be involved in both cell proliferation (growth) and angiogenesis (blood supply) -- two important processes that enable cancer growth. These kinases included Raf kinase, VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-B, KIT, FLT-3 and RET.

Nexavar is currently approved in more than 40 countries for liver cancer and in more than 70 countries for the treatment of patients with advanced kidney cancer. Nexavar is also being evaluated by the companies, international study groups, government agencies and individual investigators as a single agent or combination treatment in a wide range of cancers, including metastatic melanoma, lung cancer, breast cancer and as an adjuvant therapy for kidney cancer.

Important Safety Considerations for Patients Taking Nexavar

Based on the currently approved U.S. package insert for the treatment of patients with unresectable hepatocellular carcinoma, hypertension may occur early in the course of therapy and blood pressure should be monitored weekly during the first six weeks of therapy and treated as needed. Bleeding with a fatal outcome from any site was reported in 2.4% for Nexavar and 4% in placebo. The incidence of treatment-emergent cardiac ischemia/infarction was 2.7% for Nexavar vs. 1.3% for placebo. Most common adverse events reported with Nexavar in patients with unresectable HCC were diarrhea, fatigue, abdominal pain, weight loss, anorexia, nausea and hand-foot skin reaction. Grade 3/4 adverse events were 45% for Nexavar vs. 32% for placebo. Women of child-bearing potential should be advised to avoid becoming pregnant and advised against breast-feeding. In cases of any severe or persistent side effects, temporary treatment interruption, dose modification or permanent discontinuation should be considered.

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

(1) Ferlay J, et al., GLOBOCAN 2002. Cancer Incidence, Mortality and Prevalence Worldwide. IARC CancerBase No.5, Version 2.0. IARCPress, Lyon, 2004. Available at: http://www-dep.iarc.fr. Accessed May 2008.

(2) 2005 Cancer Register System (CRS) annual report, http://crs.cph.ntu.edu.tw/crs_c/annual.html. Accessed May 12, 2008.

(3) Del Pozo AC, Lopez P. Management of hepatocellular carcinoma. Clin Liver Dis 2007 May;11(2):305-21.

For more information, visit www.onyx-pharm.com and www.bayer.com.