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www.fdanews.com/articles/88606-exelixis-suspends-enrollment-in-cancer-drug-trial

EXELIXIS SUSPENDS ENROLLMENT IN CANCER DRUG TRIAL

November 3, 2006

Exelixis announced that it has suspended enrollment of new patients in the XL999 clinical trial program until further data have been collected and analyzed. The company currently anticipates that it will incur a delay in the clinical program for XL999 of between two weeks and three months.

Exelixis suspended enrollment after a preliminary review of patient data relating to cardiovascular adverse events for the month of October. Through the end of September, 117 patients had been dosed with XL999, of whom 12 (10.3 percent) experienced serious adverse cardiovascular events. However, four of the 14 patients enrolled during October also experienced such events, which raised a concern with the company's internal safety monitoring committee.

The company therefore decided to suspend enrollment of new patients pending further review of the data. Because 115 of the 131 subjects enrolled in the XL999 clinical program to date have received repeated doses of XL999 (every week or every other week) ranging from two doses (two weeks) to 53 doses (approximately two years) with no reported cardiac toxicities, the company has elected to allow patients already enrolled to continue to receive XL999.

XL999 is a potent inhibitor of key RTKs implicated in the development and maintenance of tumor vasculature and in the proliferation of some tumor cells.