Onyx Pharmaceuticals Achieves Milestone in Cancer Program with Pfizer
PD332991 Enters Phase I Human Clinical Trials
Richmond, California — Sep. 20, 2004
Contact:
Julie Wood
510-262-8757
Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) announced today that its collaborator, Pfizer Inc, has initiated Phase I clinical trials for an anti-cancer compound discovered during the two companies' research collaboration. The initiation of human clinical trials triggers a $500,000 milestone payment to Onyx.
Pfizer is managing and funding all clinical development and commercialization activities for this compound, known as PD332991. In exchange, Onyx will receive a high single-digit royalty if PD332991 is commercialized. Onyx will also receive milestone payments associated with the achievement of certain clinical and regulatory events.
This novel compound is intended to intervene in the misregulated cell cycle of tumor cells by inhibiting a key enzyme, cyclin-dependent kinase 4 (cdk4). The normal cell cycle consists of distinct phases during which the cell's DNA is copied and the cell divides. Cdks are enzymes that operate as switches to move the cell through these stages by controlling protein phosphorylation. PD332991 is a cdk4 inhibitor active in the initial stage (G1) of the cell cycle, a phase where most human tumors have abnormal regulation. It is anticipated that blocking cdk4 activity may provide an approach to inhibiting proliferation of tumor cells at a key step in the cell cycle, one where cancer cells become distinct from normal cells.
Earlier this year, at the annual meeting of the American Association for Cancer Research (AACR), Pfizer researchers reported that PD332991 is a highly selective and potent cdk4 inhibitor. It was shown to arrest the cell in the G1 phase of the cell cycle, preventing it from entering the S phase, the step where the cell's DNA is replicated. Pfizer researchers demonstrated that oral administration of PD332991 resulted in marked tumor regression in in vivo models. Thus it appears that PD332991 has the potential to shrink tumors, as well as to prevent tumor growth.
Onyx Pharmaceuticals 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 BAY 43-9006 with Bayer Pharmaceuticals Corporation. For more information about Onyx's pipeline and activities, visit the company's website at www.onyx pharm.com.
This news release contains forward-looking statements regarding expectations about the development of a novel Cdk inhibitor, including further clinical testing and the timing of such clinical trials; and the company's expectations or beliefs of the compound's commercial potential. These forward-looking statements involve a number of risks and uncertainties that could cause actual events to differ from the company's expectations. These risks are addressed in the company's periodic reports filed with the Securities and Exchange Commission, including but not limited to its Annual Report on Form 10-K filed on March 15, 2004 and its Quarterly Reports on Form 10-Q.
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