2007 Press Releases

Nexavar First FDA-Approved Drug Therapy for Liver Cancer

Only Systemic Therapy Proven to Significantly Improve Overall Survival in Patients with Liver Cancer

WAYNE, NJ and EMERYVILLE, CA — Nov. 19, 2007

Bayer HealthCare Pharmaceuticals and Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) today announced that the U.S. Food and Drug Administration (FDA) has approved a supplemental New Drug Application for Nexavar® (sorafenib) tablets for the treatment of patients with unresectable hepatocellular carcinoma (HCC), or liver cancer. Nexavar, an oral anticancer drug, is the first approved systemic therapy for liver cancer and the only one shown to significantly improve overall survival in patients with the disease. In 2005 Nexavar became the first new treatment in more than a decade for advanced kidney cancer, and is currently approved in more than 60 countries for this indication.

"The approval of Nexavar in liver cancer marks the second time in two years that this novel kinase inhibitor has been granted FDA approval on a Priority Review basis, making it rapidly available to patients who previously had limited treatment options," said Arthur Higgins, chairman of the Executive Committee of Bayer HealthCare. "This milestone will likely establish Nexavar as the standard systemic therapy for the treatment of liver cancer, and is a turning point in improving treatment outcomes in patients facing the devastating impact of this disease."

"Liver cancer is one of the cancers in which the number of related deaths continues to increase," said Hollings C. Renton, chairman, president and chief executive officer of Onyx Pharmaceuticals, Inc. "This second approval for Nexavar demonstrates our commitment to expediting the clinical development of this innovative therapy to treat today's unmet needs in cancer. We are grateful to the patients, families and investigators who make this important research possible."

HCC, the most common form of liver cancer, is responsible for about 90 percent of the primary malignant liver tumors in adults.1,2 Liver cancer is the sixth most common cancer in the world and the third leading cause of cancer-related deaths globally.3 More than 600,000 cases of liver cancer are diagnosed worldwide each year3 (about 19,000 in the United States,4 54,0005 in Europe,6 and 390,000 in China, Korea and Japan6) and incidence is increasing.7 In 2002 approximately 600,000 people died of liver cancer including 13,000 in the United States, 57,0005 in Europe and approximately 360,000 in China, Korea and Japan.6 Currently, the 5-year survival rate for liver cancer patients in the United States is 11 percent.8

"The American Liver Foundation (ALF) is always pleased when new therapies prove effective for those affected by liver disease. Researchers worldwide, including those supported by ALF, have spent decades studying liver cancer," said James L. Boyer, M.D., chairman, board of directors, American Liver Foundation. "This new treatment provides a valuable option for liver cancer patients and will enable ALF to further promote the treatment of liver disease through our education and advocacy efforts."

The companies also announced that an innovative patient support program - Resources for Expert Assistance and Care Helpline (REACH®) - is available to answer questions about Nexavar treatment, reimbursement, and patient support. For more information, healthcare providers and patients may contact the REACH program at 1.866.NEXAVAR (1.866.639.2827).

Phase 3 Data Summary
The FDA approval was based on positive data from the international Phase 3 placebo-controlled Sorafenib HCC Assessment Randomized Protocol (SHARP) trial which demonstrated that Nexavar improved overall survival by 44 percent in patients with HCC (HR=0.69; p=0.0006) versus placebo. In the study, median overall survival was 10.7 months in Nexavar-treated patients compared to 7.9 months in those taking placebo. No indication of imbalances was observed in serious adverse events between the Nexavar and placebo-treated groups with the most commonly observed adverse events in patients receiving Nexavar being diarrhea and hand-foot skin reaction. Based on these data, the European Commission granted marketing authorization to Nexavar for the treatment of patients with hepatocellular carcinoma on October 29, 2007.

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 Raf/MEK/ERK has a role in HCC; therefore, blocking signaling through Raf-1 may offer therapeutic benefits in HCC.

Important Safety Considerations for U.S. Patients Taking Nexavar
Based on the currently approved 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 vs. 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, 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).

About Onyx Pharmaceuticals, Inc.
Onyx Pharmaceuticals, Inc. is a biopharmaceutical company developing innovative therapies that target the molecular mechanisms that cause cancer. The company is developing Nexavar®, a small molecule drug, with Bayer HealthCare Pharmaceuticals Inc. Nexavar is approved for the treatment of advanced kidney cancer in more than 60 countries. For more information about Onyx's pipeline and activities, visit the company's web site at: www.onyx-pharm.com.

About Bayer HealthCare Pharmaceuticals Inc.
Bayer HealthCare Pharmaceuticals Inc. is the U.S.-based pharmaceuticals unit of Bayer HealthCare LLC, a division of Bayer AG. One of the world's leading, innovative companies in the healthcare and medical products industry, Bayer HealthCare combines the global activities of the Animal Health, Consumer Care, Diabetes Care, and Pharmaceuticals divisions. In the U.S., Bayer HealthCare Pharmaceuticals comprises the following business units: Women's Healthcare, Diagnostic Imaging, Specialized Therapeutics, Hematology/Cardiology and Oncology. The company's aim is to discover and manufacture products that will improve human health worldwide by diagnosing, preventing and treating diseases.

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 our annual and interim reports filed with the Frankfurt Stock Exchange. The company 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, 2006, 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 HealthCare Pharmaceuticals Inc.


References
1. World Health Organization. Hepatitis B. Available at: http://www.who.int/csr/disease/hepatitis/whocdscsrlyo20022/en/. Accessed April 10, 2007
2. Penn State Milton S. Hershey Medical Center College of Medicine. Malignant Hepatoma. Available at: http://www.hmc.psu.edu/healthinfo/m/malignanthepatoma.htm. Accessed April 10, 2007.
3. International Agency for Cancer Research. GLOBOCAN 2002. Available at: http://www-dep.iarc.fr. Accessed April 23, 2007.
4. Jemal A et al. CA Cancer J Clin. 2007;57:43-66.
5. The reported mortality of HCC in Europe is higher than the incidence of HCC in Europe. This is due to the overestimation of mortality by occasional counting of metastatic cancers that have spread to the liver, and underestimation of incidence as a result of a lack of technology for early detection and diagnosis of HCC. Source: International Agency for Research on Cancer.
6. 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 April 10, 2007.
7. Ries LAG, Melbert D, Krapcho M, Mariotto A, Miller BA, Feuer EJ, Clegg L, Horner MJ, Howlader N, Eisner MP, Reichman M, Edwards BK (eds). SEER Cancer Statistics Review, 1975-2004, National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1975_2004/, based on November 2006 SEER data submission, posted to the SEER web site, 2007.
8. American Cancer Society. Cancer Facts & Figures 2007. Atlanta: American Cancer Society: 2007.