FDA Grants Orphan Drug Designation to Nexavar for the Treatment of Hepatocellular Carcinoma

Wednesday - April 26, 2006, WEST HAVEN, CT and EMERYVILLE, CA – Bayer Pharmaceuticals Corporation (NYSE: BAY) and Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) announced today that Nexavar® (sorafenib) tablets has been granted orphan drug status for the treatment of hepatocellular carcinoma (HCC), or liver cancer, by the U.S. Food and Drug Administration (FDA). A similar designation has been granted by the European Commission this month.

“We are very encouraged by the collaboration of the FDA as well as the European Regulatory bodies in our research surrounding this highly fatal disease,” said Susan Kelley, M.D., vice president, Oncology, Bayer Pharmaceuticals Corporation. “It fuels our efforts to strive toward a novel therapy, for liver cancer patients worldwide.”

At the 16th American Association for Cancer Research-National Cancer Institute-European Organization for Research and Treatment of Cancer (AACR-NCI-EORTC) meeting in 2004, investigators reported that in a Phase II single agent study, 43 percent of patients treated with Nexavar experienced stable disease for at least four months and an additional nine percent of patients experienced tumor shrinkage. The most common grade 3/4 drug-related toxicities were fatigue (9.5 percent), diarrhea (8 percent), and hand–foot skin reaction (5 percent). The toxicity profile of Nexavar was similar to previously reported safety analysis in patients with renal cell carcinoma.

A Phase III trial of Nexavar administered as a single agent is ongoing. It is designed to measure differences in overall survival, time-to-symptom progression and time-to-tumor progression of Nexavar versus placebo in liver cancer patients. A randomized Phase II trial for liver cancer patients to evaluate the efficacy of Nexavar in combination with the chemotherapeutic agent doxorubicin is also ongoing.

“Liver cancer is such an aggressive disease that patients diagnosed with it rarely live beyond two years,” said Dr. Jordi Bruix, head of the Barcelona Clinic Liver Cancer Group at the University of Barcelona in Spain. “The global medical community recognizes the need for new treatments in liver cancer and I am hopeful of the potential of Nexavar in this patient population.” Dr. Bruix is co-primary investigator of the Phase III trial along with Dr. Josep Llovet, senior scientist of the division of liver disease at Mount Sinai School of Medicine in New York.

In December 2005, Nexavar received approval from the FDA to treat patients with advanced renal cell carcinoma (RCC), or kidney cancer. The European Commission has also granted an orphan medicinal product designation for Nexavar in renal cell carcinoma and a Marketing Authorization Application (MAA) had been submitted to the European Medicines Agency (EMEA) in September 2005 for treatment of patients with kidney cancer with Nexavar within the European Union.

Orphan Drug Designation in the United States
In the United States, the Orphan Drugs Act (ODA) provides for the orphan drug designation which aims to encourage the development of drugs involved in the diagnosis, prevention or treatment of a medical condition affecting fewer than 200,000 people in the country. The designation grants U.S. market exclusivity to a drug for a particular indication for a seven-year period if the sponsor complies with certain FDA specifications. Additional incentives for the sponsor include tax credits related to clinical trial expenses and a possible exemption from the FDA-user fee. The designation does not shorten the duration of the regulatory review and approval process.

About Nexavar
Nexavar is the first oral multi-kinase inhibitor that targets both the tumor cell and tumor vasculature. In preclinical models, Nexavar targeted members of two classes of kinases known to be involved in both tumor cell proliferation (tumor growth) and tumor angiogenesis (tumor blood supply) - two important cancer growth activities. These kinases included RAF kinase, VEGFR-2, VEGFR-3, PDGFR-β, KIT, and FLT-3.

Nexavar is currently in Phase III clinical trials for the treatment of liver cancer, metastatic melanoma, or skin cancer, and non-small cell lung cancer (NSCLC), and has been studied in more than 20 tumor types and in more than 8,000 clinical trial patients. In addition to company-sponsored trials, there are a variety of Nexavar studies being sponsored by government agencies, cooperative groups and individual investigators.

About Hepatocellular Carcinoma
Hepatocellular carcinoma (HCC), also known as primary liver cancer, is the most common form of liver cancer and is responsible for 80 percent of the primary malignant liver tumors in adults. It is the fifth most common cancer in the world. HCC disproportionately affects men, with four times as many men developing the disease as women. In 2002, approximately 626,000 cases of HCC were reported worldwide (15,000 in the United States and 53,600 in Europe), and more than 600,000 deaths (about 13,000 Americans and 57,000 Europeans) due to HCC were reported. The five-year relative survival rate is about seven percent.

Important Safety Considerations for U.S. Patients Taking Nexavar
Based on the current, approved package insert for the treatment of patients with advanced kidney cancer, 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. Incidence of bleeding regardless of causality was 15% for Nexavar vs. 8% for placebo and the incidence of treatment-emergent cardiac ischemia/infarction was 2.9% for Nexavar vs. 0.4% for placebo. Most common treatment-emergent adverse events with Nexavar were diarrhea, rash/desquamation, fatigue, hand-foot skin reaction, alopecia, and nausea. Grade 3/4 adverse events were 38% for Nexavar vs. 28% 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 U.S. Nexavar prescribing information, visit www.nexavar.com or call 1.866.NEXAVAR (1.866.639.2827).

About Onyx Pharmaceuticals, Inc.
Onyx Pharmaceuticals, Inc. is engaged in the development of novel cancer therapies that target the molecular basis of cancer. With its collaborators, the company is developing small molecule drugs, including Nexavar with Bayer Pharmaceuticals Corporation. For more information about Onyx’s pipeline and activities, visit the company’s web site at: www.onyx-pharm.com.

About Bayer Pharmaceuticals Corporation
Bayer Pharmaceuticals Corporation (www.bayerpharma.com) is part of the worldwide operations of Bayer HealthCare AG, a subsidiary of Bayer AG.

Bayer HealthCare AG, with sales of approximately 9.4 billion Euros in 2005, is one of the world’s leading, innovative companies in the healthcare and medical products industry. The company combines the global activities of the Animal Health, Consumer Care, Diabetes Care, Diagnostics and Pharmaceuticals divisions. Bayer Pharmaceuticals Corporation is part of the new Global Pharmaceutical Division, established January 1, 2006, which consists of the former Biological Products and Pharmaceutical Division and now comprises three business units: Hematology/Cardiology; Oncology and Primary Care. Bayer HealthCare AG employed 33,800 people worldwide in 2005.

Bayer HealthCare AG’s aim is to discover and manufacture innovative products that will improve human and animal health worldwide. The products enhance well-being and quality of life by diagnosing, preventing and treating disease.


Forward Looking Statements
This news release contains forward-looking statements based on current assumptions and forecasts made by Bayer Group management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Bayer’s public reports filed with the Frankfurt Stock Exchange and with the U.S. Securities and Exchange Commission (including its Form 20-F). Bayer assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

This news release also contains “forward-looking statements” of Onyx within the meaning of the federal securities laws. These forward-looking statements include without limitation, statements regarding the timing, progress and results of the clinical development, regulatory processes, and commercialization efforts of Nexavar. These statements are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated. Reference should be made to Onyx’s Annual Report on Form 10-K for the year ended December 31, 2005, 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.

Nexavar® (sorafenib) tablets is a registered trademark of Bayer Pharmaceuticals Corporation.

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Bayer Pharmaceuticals Corporation

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