Exelixis Presents Encouraging Phase 1 Data For XL019, A Novel Selective Inhibit...( ATLANTA Dec. 10 /- Exelixis Inc. ...),Health

ATLANTA, Dec. 10 /PRNewswire-FirstCall/ -- Exelixis, Inc. (Nasdaq: EXEL), today reported phase 1 data from an ongoing phase 1 trial of XL019 in patients with myelofibrosis, a myeloproliferative disorder (MPD). XL019 is an investigational small molecule that selectively inhibits the tyrosine kinase JAK2, one of four JAK family members activated in response to cytokines and hematopoietic growth factors. JAK2 is inappropriately activated in the majority of MPD patients and is deregulated in a number of solid tumors, including certain subtypes of lymphoma. Dr. Srdan Verstovsek from the M. D. Anderson Cancer Center, Houston, TX today presented data from an ongoing phase 1 study in an oral presentation session (Abstract #553) at the American Society of Hematology 49th Annual Meeting and Exposition, which is taking place in Atlanta, December 8th-11th.

"We are very encouraged by the results from this ongoing trial that show rapid decrease in spleen size and relief of disease-related symptoms at low doses of XL019. XL019 is a highly selective inhibitor of JAK2 that may have the potential to provide important benefit for patients with myeloproliferative disorders and other diseases driven by JAK2," said Michael Morrissey, Ph.D., president of research and development at Exelixis. "We believe that JAK2 is a critical target in myeloproliferative disorders, and effective inhibition of JAK2 may directly translate into clinical benefit. The strong linkage of JAK2 to MPDs provides a potentially quick route to market, with potential for additional opportunities in larger commercial indications. We are planning to initiate pivotal trials of XL019 in myelofibrosis patients in 2008."

Trial Design

The phase 1 dose escalation study of XL019 is ongoing in subjects with primary myelofibrosis (MF) and post-polycythemia vera/essential thrombocythemia MF. To date nine patients have been enrolled. The primary objective of this study is to determine the safety and tol
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