Exelixis drug induces antitumor activity

Consistent with previously reported results from this study, XL999 showed preliminary evidence of antitumor activity. Cardiac failure and elevated hepatic transaminases were identified as dose-limiting toxicities.

In the phase I trial patients were evaluated for safety and tumor response assessments. Three patients have had partial responses. Ten other patients have had stable disease for 3 to 25.5 months.

A phase II clinical program for XL999 was initiated in December 2005 and is ongoing. The phase II program is composed of six trials that will evaluate XL999 in colon, ovarian and non-small cell lung cancer, renal cell carcinoma, acute myelogenous leukemia and multiple myeloma.

As reported previously, enrollment in the phase II trial has been suspended pending further review of data relating to cardiovascular adverse events. 4 of the 14 patients enrolled during October also experienced such events, which raised a concern with the company’s internal safety monitoring committee.

“We are placing patients’ safety first and are diligently analyzing the clinical data available for XL999 to determine the appropriate next steps in the development of this novel cancer therapy,” said Gisela Schwab, senior vice president of Exelixis.