Federal regulators approved a new four-in-one combination pill to treat HIV, the virus that causes AIDS. The Food and Drug Administration approved sales of Genvoya (pronounced jehn-VOY’ah) from Gilead Sciences, which is the top maker of HIV medicines. The drug combines three existing Gilead HIV drugs: Vitekta, Tybost and Emtriva, and adds a new version of tenofovir, the active ingredient in Gilead’s widely used Viread. A chemical cousin, called Tenofovir Alafenamide, gets more of the drug into cells where HIV copies itself. The annual list price for Genvoya will be $31,362, about the same as Gilead’s older four-in-one HIV drug, Stribild.