Phase III Trial of Nexavar in Patients with Advanced Melanoma Does Not Meet Primary Endpoint

WEST HAVEN, Conn. and EMERYVILLE, Calif. — Dec. 04, 2006

Bayer Pharmaceuticals Corporation (NYSE: BAY) and Onyx Pharmaceuticals, Inc.
(Nasdaq: ONXX) today announced that a Phase III trial administering Nexavar®
(sorafenib) or placebo tablets in combination with the chemotherapeutic agents
carboplatin and paclitaxel in patients with advanced melanoma did not meet its
primary endpoint of improving progression-free survival (PFS). The treatment
effect was comparable in each arm. Data from the study will be presented at
an upcoming scientific congress.

“We are disappointed, first and foremost, for the patients with refractory
metastatic melanoma for whom treatment options are so limited,” said Hollings
C. Renton, Onyx’s chairman, president, and chief executive officer. “However,
this trial does not change our commitment to, and belief in, Nexavar. We hope
to demonstrate utility in a wide variety of tumors and we will continue to
broaden our clinical program, including increasing our attention to the more
common malignancies in which anti-angiogenics have demonstrated activity.”

Phase III Study Design
The international Phase III, double-blind, randomized, placebo-controlled
trial evaluated Nexavar when administered in combination with a standard
dosing schedule (21-day cycles) of carboplatin and paclitaxel. Two hundred
seventy patients progressing after one previous systemic chemotherapeutic
treatment (with either dacarbazine (DTIC) or temozolomide) were enrolled into
the study. The study was designed to measure the safety and efficacy of
Nexavar when co-administered with chemotherapy, and had PFS as its primary
endpoint. PFS is defined as the time that a patient lives without meaningful
tumor growth. The safety profile of these agents in combination (Nexavar with
carboplatin/paclitaxel) was comparable to those previously reported for these
agents in combination.

About Melanoma
In the United States (U.S.), the incidence of melanoma has doubled in the
last 25 years. Melanoma accounts for about four percent of skin cancer cases,
but is responsible for approximately 77 percent of skin cancer deaths. In
2006, it is estimated that over 62,000 new cases of melanoma will be diagnosed
in the U.S., with close to 8,000 people expected to die from the disease.
Worldwide, it is estimated that about 132,000 people are diagnosed with
melanoma and more than 40,000 die from the disease each year.

About Nexavar
Nexavar is an 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 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, and FLT-3.

Nexavar is currently approved in a number of countries, including the U.S.
and the European Union, for the treatment of patients with advanced kidney
cancer. In addition, Nexavar is being evaluated as a single agent in a Phase
III clinical trial for the treatment of advanced hepatocellular carcinoma
(HCC), or liver cancer, a study that has completed enrollment. A Phase III
clinical trial of Nexavar combined with carboplatin and paclitaxel in non-
small cell lung cancer (NSCLC) for treatment-naive patients was initiated in
the first half of 2006. In addition to company-sponsored trials, there are a
number of Nexavar studies being sponsored by government agencies, cooperative
groups, and individual investigators, including a Phase III trial evaluating
Nexavar in the adjuvant treatment of RCC.

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 percent for Nexavar vs. 8 percent for placebo,
and the incidence of treatment-emergent cardiac ischemia/infarction was 2.9
percent for Nexavar vs. 0.4 percent for placebo. Gastrointestinal perforation
was an uncommon event and has been reported in less than 1% of patients taking
Nexavar. 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 percent for Nexavar vs. 28 percent
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 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(R), a small molecule drug, with Bayer
Pharmaceuticals Corporation. Nexavar has been approved for the treatment of
advanced kidney cancer. For more information about Onyx’s pipeline and
activities, visit the company’s web site at:

About Bayer Pharmaceuticals Corporation
Bayer Pharmaceuticals Corporation ( is part of the
worldwide operations of Bayer HealthCare AG, a subsidiary of Bayer AG. Bayer
HealthCare is one of the world’s leading, innovative companies in the
healthcare and medical products industry and is based in Leverkusen, Germany.
Bayer HeathCare generated sales amounting to some 9.4 billion euros and
employed 33,800 people worldwide in 2005.

The company combines the global activities of the Animal Health, Consumer
Care, Diabetes Care, Diagnostics and Pharmaceuticals divisions. The new
Pharmaceuticals division was established on January 1, 2006, and comprises the
former Biological Products and Pharmaceutical divisions. Bayer HealthCare
Pharmaceuticals now has three business units: Hematology/Cardiology, Oncology
and Primary Care.

Bayer HealthCare’s aim is to discover and manufacture products that will
improve human and animal health worldwide. The products enhance well-being
and quality of life 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 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

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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