Adverse events force delay in Exelixis trial

Exelixis says it will delay new enrollment for a clinical trial of the cardiovascular drug XL999 for up to three months after about 10 percent of the patients in the study experienced severe adverse cardiovascular events. Patients with no reported toxicity will continue in the study. Twelve of the 117 patients enrolled in the study experienced adverse events. But Exelixis emphasized that 115 of the 131 volunteers now enrolled in the study had experienced no adverse effects and would continue in the trial. Exelixis stock tumbled about 10 percent on the news.

"Since all but one of the events occurred on first administration of XL999, we are continuing to treat those patients presently enrolled in the trial," said President and Chief Executive George A. Scangos, in a statement.

- here's the AP report on the enrollment delay