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Gilead Sciences stops successful cancer drug study

FOSTER CITY, Calif. (AP) -- Gilead Sciences said Wednesday it stopped a late-stage clinical trial of a cancer treatment because it was clear the drug was working.

Gilead was studying idelalisib as a treatment for chronic lymphocytic leukemia. The company said an early analysis of data from the study showed that patients who were treated with idelalisib had a longer time before the resumption of disease progression or death. A panel of independent monitors recommended that Gilead stop the trial.

Shares of Gilead Sciences Inc. rose $1.85, or 3.1 percent, to $60.75 in aftermarket trading.

The trial compared a combination of idelalisib and Rituxan, and older cancer drug, to Rituxan alone. Patients in the trial had chronic lymphocytic leukemia and had been treated before, but were not fit for additional chemotherapy.

In September, Gilead asked the Food and Drug Administration to approve idelalisib as a treatment for slow-growing non-Hodgkin lymphoma that has recurred after treatment. It plans to file for marketing approval in the European Union later this year.

Gilead shares lost 48 cents to $58.90 on Wednesday in regular-session trading before the idelalisib announcement.