Onyx Pharmaceuticals Acquires Option to License Novel Highly Specific JAK2 Inhibitors ...(with staged investments as value-creatin...),Health

SB1518 (ONX 0803) has been designed to suppress the overactivity of mutant JAK2 and is currently in multiple Phase 1 studies. Data from these Phase 1 dose-ranging studies, evaluating the compound in patients with primary myelofibrosis, are anticipated in the first half of 2009. SB1578 (ONX 0805) is currently in preclinical development.

Under normal circumstances, activation of JAK2 stimulates blood cell production. Genetic mutations in the JAK2 enzyme result in up-regulated activity and are implicated in myeloproliferative diseases (MPD), conditions characterized by an overproduction of blood cells in the bone marrow. The MPD conditions where JAK2 mutations are most commonly found are: polycythemia vera (PV), essential thrombocytopenia (ET), and primary myelofibrosis (MF). The JAK2 signaling pathway is also known to play a critical role in the proliferation of certain types of cancer cells and the anti-inflammatory pathway, suggesting JAK2 inhibitors may be able to play a role in the treatment of solid tumors and other diseases such as rheumatoid arthritis or psoriasis.

"Given its specificity for the JAK2 kinase and the encouraging early clinical activity and safety observed so far, we believe that SB1518 (ONX 0803) and SB1578 (ONX 0805) may be effective and well-tolerated treatments for a number of debilitating conditions with potential applicability beyond MF and MPD," said Juergen Lasowski, Ph.D., senior vice president of corporate development at Onyx.

About Onyx Pharmaceuticals, Inc.

Onyx Pharmaceuticals, Inc. is a biopharmaceutical company committed to improving the lives of people with cancer by changing the way cancer is treated(TM). The company, in collaboration with Bayer HealthCare Pharmaceuticals, Inc., is developing and marketing Nexavar(R), a small molecule drug. Nexavar is currently approved for the
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