Exelixis Reports Encouraging Phase 1 Data for XL1...( Greater Than 50% Response Rate and ...),Health

Greater Than 50% Response Rate and 100% Disease Control Rate Observed in

Patients with Medullary Thyroid Cancer

CHICAGO, June 1 /PRNewswire-FirstCall/ -- Exelixis, Inc. (Nasdaq: EXEL) reported encouraging new data from an ongoing phase 1 clinical trial of XL184, a novel small molecule inhibitor of MET, VEGFR2, and RET, in patients with advanced malignancies. The maximum tolerated dose (MTD) for XL184 has been determined to be 175 mg/day given orally daily. Based on initial signs of clinical activity in a number of patients with medullary thyroid cancer (MTC) during the dose-escalation phase, the trial has been expanded to treat an additional 20 patients with MTC at the MTD. Ravi Salgia, MD, PhD, Associate Professor of Medicine and Director of the Thoracic Oncology Research Program at the University of Chicago Medical Center, and a lead investigator in the trial, presented the data today in the Developmental Therapeutics: Molecular Therapeutics oral abstract session (Abstract #3522) at the 44th Annual Meeting of the American Society of Clinical Oncology (ASCO).

Sixty patients were evaluated for safety, pharmacokinetics, and tumor response as of the May 1, 2008 cutoff; further data also were provided for nine additional patients after the cutoff. Across all tumor types, 10 patients had partial responses as determined by RECIST criteria: 9 partial responses were observed in patients with MTC (5 confirmed), and 1 in a patient with a neuroendocrine tumor. An additional 25 patients with various tumor types had stable disease for at least 3 months, including 8 patients with MTC. The disease control rate (percentage of patients with partial responses or prolonged stable disease >3 months) in patients with MTC was
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