November 02, 2004

Bayer and Onyx Announce Results of Phase I Studies Evaluating BAY 43-9006 in Combination with Conventional Chemotherapy Drugs

- Bayer Pharmaceuticals Corporation (NYSE: BAY) and Onyx
Pharmaceuticals, Inc. (Nasdaq: ONXX) announced results from several Phase I
clinical trials of BAY 43-9006 administered in combination with conventional
chemotherapy drugs in patients with various tumor types including, hepatic
cancer and colorectal cancer. The data were presented at the 29th European
Society of Medical Oncology (ESMO) meeting in Vienna, Austria.

Data from these Phase I safety and pharmacokinetic (metabolism) interaction
studies showed that BAY 43-9006 could be combined with the other anticancer
agents evaluated (doxorubicin, oxaliplatin, fluorouracil and leucovorin). In
addition, data show that BAY 43-9006 required no dose adjustment when
administered with ketoconazole (CYP3A inhibitor). Safety data generated across
all studies showed no unexpected treatment-related adverse events.

BAY 43-9006, a novel RAF kinase and VEGFR inhibitor under investigation for the
treatment of different types of cancer, combines two anticancer activities:
inhibition of tumor cell proliferation and angiogenesis (the growth of new
blood vessels).

BAY 43-9006 ESMO Data

BAY 43-9006 data being presented at this year's ESMO meeting include:

- Results of a Phase I trial of BAY 43-9006 in combination with doxorubicin in
patients with primary hepatic cancer. H. Richly, MD.

- Results of a Phase I combination trial of BAY 43-9006 with oxaliplatin in
patients with colorectal cancer. P. Kupsch, MD.

- Phase I trial of BAY 43-9006 in combination with 5-fluorouracil (5-FU) and
leucovorin (LCV) in patients with advanced refractory solid tumors. A. Figer,

- A randomized Phase I clinical and biologic study of two schedules of the
C-RAF kinase inhibitor BAY 43-9006 in patients with Myelodysplastic Syndrome
(MDS) or Acute Myeloid Leukemia (AML): A NCI Canada Clinical Trials Group
study. M. Crump, MD.

- Lack of effect of ketoconazole, a CYP3A inhibitor, on BAY 43-9006 clinical
pharmacokinetics. C.D. Lathia, Ph. D.

About BAY 43-9006

BAY 43-9006, a novel investigational drug candidate, has demonstrated
anti-proliferative and anti-angiogenic properties - two important anticancer
activities. In preclinical models, BAY 43-9006 inhibited tumor cell
proliferation by targeting the RAF/MEK/ERK signaling pathway at the level of
RAF kinase. BAY 43-9006 also exerted an antiangiogenic effect by targeting the
receptor tyrosine kinases VEGFR-2 and PDGFR and their associated signaling

BAY 43-9006 is currently undergoing Phase III evaluation for the treatment of
advanced kidney cancer and Bayer and Onyx intend to initiate additional Phase
II and Phase III trials in other tumor types. For more information on BAY
43-9006 clinical trials, visit

Bayer HealthCare AG, a subgroup of Bayer AG with sales of approximately 8.9
billion Euro in 2003, is one of the world's leading, innovative companies in
the health care and medical products industry.

The company combines the global activities of the divisions Animal Health,
Biological Products, Consumer Care, Diagnostics and Pharmaceuticals. 34,600
people are employed by Bayer HealthCare worldwide.

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

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