Gilead asks FDA to approve new HIV drug booster

An important boosting agent in Gilead Sciences Inc.'s experimental four-in-one Quad pill for HIV patients was formally submitted for approval Thursday to the Food and Drug Administration.

Foster City-based Gilead (NASDAQ: GILD) said it asked the FDA to approve cobicistat, a boosting agent that increases blood levels of some protease inhibitors, including elvitegravir. The booster allows elvitegravir, which Gilead submitted Wednesday for approval, to be given once a day as part of the Quad pill.