Trial to be Stopped Early to Allow All Patients Access to Nexavar

Berlin, August 27, 2007 - Bayer HealthCare and Onyx Pharmaceuticals, Inc. today announced that a planned review by an independent data monitoring committee (DMC) found that Nexavar (sorafenib) tablets significantly improved overall survival, progression-free survival, and time to progression in an Asia-Pacific regional Phase III trial of patients with advanced hepatocellular carcinoma (HCC), the most common form of liver cancer. Based on the DMC's recommendation, the trial will be stopped to allow all patients to receive treatment with Nexavar. Data from this study will be submitted for presentation at an upcoming scientific meeting.

The Asia-Pacific liver cancer study was conducted at the request of Asian health authorities in order to provide supplemental information on Nexavar's efficacy and safety in Asian-Pacific patient populations.

Bayer has completed supplemental regulatory filings in several countries/regions including Europe, China, and the U.S. for Nexavar in the treatment of liver cancer. These filings were based on positive data from the pivotal Phase III SHARP study announced earlier this year. Additional regulatory submissions for Nexavar in liver cancer are being finalized.

"Liver cancer incidence continues to rise in the Asia-Pacific region, due to the high prevalence of hepatitis B virus infections," said Dr. Ann-Lii Cheng, principal investigator and Professor of Medicine, National Taiwan University Hospital. "These study results confirm that Nexavar's efficacy and tolerability in liver cancer extends across ethnic groups and geographies and suggest that Nexavar could meet a tremendous unmet need for patients and families impacted by this devastating disease."

Hepatocellular carcinoma (HCC) is the most common form of liver cancer and is responsible for about 90 percent of the primary malignant liver tumors in adults. It is the sixth most common cancer in the world and the third leading cause of cancer-related deaths globally. Over 600,000 new cases of HCC are diagnosed globally each year. In 2002, approximately 600,000 people died of HCC, including approximately 360,000 in China, Korea, and Japan, 13,000 in the United States and 57,000 in Europe. Risk factors for liver cancer include ongoing (chronic) infection with the hepatitis B virus (HBV) and/or hepatitis C virus (HCV).

About the Asia-Pacific Liver Cancer Study

This double-blind, randomized, placebo-controlled Phase III trial was designed to evaluate Nexavar in patients with advanced HCC, or primary liver cancer, who had no prior systemic therapy. The study enrolled 226 patients from sites in China, Korea, and Taiwan. The primary objectives of the study were to compare overall survival, progression-free survival, and time to progression (TTP) in patients administered Nexavar 400 mg twice daily versus patients administered placebo.

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. Preclinical models have also demonstrated that the Raf/MEK/ERK system has a role in HCC; therefore blocking signaling through Raf-1 may offer therapeutic benefits in HCC.

Nexavar is currently approved in more than 50 countries, including the United States and those in the European Union, for the treatment of patients with advanced kidney cancer. In Europe, Nexavar is approved for the treatment of patients with advanced renal cell carcinoma (RCC) who have failed prior interferon-alpha or interleukin-2 based therapy or are considered unsuitable for such therapy.

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 other cancers, including adjuvant therapy for kidney cancers, metastatic melanoma, breast cancer, and non-small cell lung cancer (NSCLC). In addition, the companies recently confirmed that they are going to conduct a company-sponsored Phase III study of Nexavar in the adjuvant treatment of HCC following the complete removal of early stage liver cancer.