Exelixis shares rise after FDA plans priority review for potential cancer treatment

Shares of Exelixis jumped in premarket trading Thursday after U.S. regulators said they would give a faster review to the drugmaker's potential treatment for a deadly form of skin cancer.

The Food and Drug Administration granted a priority review for an application for the drug, cobimetinib, to be used in combination with another treatment on patients with advanced melanoma that has a certain genetic mutation. FDA drug reviews usually take ten months, but the agency said it will make a decision on this treatment combination by Aug. 11.

Exelixis, which is based in South San Francisco, California, discovered cobimetinib and is working with Genentech, a unit of Swiss drugmaker Roche, to test the treatment.

The drugmakers said patients taking a combination of cobimetinib and vemurafenib in late-stage research experienced a median progression-free survival period of nearly 10 months compared to slightly more than 6 months for those who just took vemurafenib. Progression-free survival measures the time from the start of treatment until a patient's cancer begins advancing again, or the patient dies.

Researchers also are studying the drug as a potential treatment for some types of lung, colorectal and breast cancers.

Exelixis Inc. shares were up almost 7 percent, or 19 cents, to $2.92 less than an hour before the opening bell Thursday. The stock had already climbed 90 percent so far this year, as of Wednesday's close.