Gilead Stops Leukemia Drug Trial Early on Patient Benefit

Gilead Sciences Inc. (GILD), the world’s largest biotechnology company by market value, said it is stopping a late-stage study of the cancer drug idelalisib early because of improvement seen in patients taking the drug.

Gilead is stopping the study in patients with chronic lymphocytic leukemia after an interim analysis showed those taking idelalisib plus another medicine, Rituxan, survived longer without their cancer progressing than those taking Rituxan alone, the Foster City, California-based company said today in a statement.

The trial, from the third and final stage generally required for regulatory approval, was in patients who have tried other medicines and who aren’t fit for chemotherapy. A cancer of the bone marrow and white blood cells, CLL is the second-most common type of leukemia in adults and usually affects people in middle age or older, according to the National Institutes of Health.

“Given the significant unmet medical need in CLL, particularly in this population of patients who are not fit for chemotherapy, we are pleased that idelalisib has shown a clinically meaningful benefit for patients,” Norbert W. Bischofberger, Gilead’s chief scientific officer, said in the statement.

Gilead gained 3.4 percent to $60.90 at 4:41 p.m. New York time in extended trading. Earlier, the company’s shares declined less than 1 percent to close at $58.90. Gilead has increased 60 percent this year.

The company said it has applied for approval of idelalisib in non-Hodgkin’s lymphoma and will talk with U.S. regulators about a filing for the drug in chronic lymphocytic leukemia.

Those in the trial will continue receiving the cancer drug and those who were receiving Roche Holding AG’s Rituxan alone will be eligible to receive idelalisib in an extension study, Gilead said.

To contact the reporter on this story: Meg Tirrell in New York at

To contact the editor responsible for this story: Reg Gale at

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