Interim Phase 2 Data for Exelixis' XL880 Show Anti-Tumor Activity in Papillary Renal C...( Tumor shrinkage observed...),Health

Tumor shrinkage observed in nearly 80% of patients

SAN FRANCISCO, Oct. 24 /PRNewswire-FirstCall/ -- Exelixis, Inc. (Nasdaq: EXEL) today reported encouraging data from an ongoing phase 2 trial of XL880, an inhibitor of MET and VEGFR2 kinases, in patients with papillary renal cell carcinoma (PRC). Of 19 patients with measurable disease evaluable for tumor responses, 15 (79%) have had a decrease in tumor size (4-33%), including one patient with a partial response. All 19 evaluable patients with at least one post-baseline tumor assessment have had stable disease for at least three months, including 12 patients with stable disease for six months to 15+ months. Results of preliminary analyses of plasma biomarkers and tumor samples are consistent with inhibition of angiogenesis and proliferation and an increase in apoptosis. Data were presented today in a poster session (Abstract #B249) at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics, which is being held October 22-26, 2007 in San Francisco.

"The phase 2 trial of XL880 in PRC was supported both by the biology of the disease, which frequently is associated with activating mutations or amplifications in MET, and the favorable responses observed in patients with PRC in the reported phase 1 study of the compound," said Michael Morrissey, Ph.D., Exelixis' president of research and development. "We believe that today's data, which show that the significant majority of patients on study have experienced tumor shrinkage with prolonged duration of stable disease, highlight the potential utility of XL880 and its potent effects in modulating both MET and VEGFR2 in the clinical setting. We are excited about the potential
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