Posted Wednesday, August 17, 2011 --- 8:45 a.m.

WASHINGTON (AP) -- The Food and Drug Administration has approved a first-of-its-kind drug to treat the deadliest form of skin cancer by targeting a particular genetic mutation found in about half of patients.

The pill called Zelboraf, made by Roche, is the first treatment for melanoma that targets a specific gene found in skin-cancer tumors. The FDA also approved a test to screen patients for the mutation.

The drug was studied in 675 patients who received either Zelboraf or a chemotherapy drug. The study is ongoing, but 77 percent of people on Zelboraf are alive, compared with 64 percent of those taking the older drug, according to the FDA.

More than 68,000 cases of melanoma were diagnosed in the U.S. last year.

Copyright 2011 by The Associated Press. All Rights Reserved.