WASHINGTON  - A new pill to treat HIV infection - combining two previously approved drugs plus two new ones - has been approved for adults living with the virus that causes AIDS, US regulators said. The single daily dose of Stribild provides a complete treatment regimen for HIV infection, the US Food and Drug Administration said in a statement, and is meant for people who have not already received treatment with other HIV drugs. “Through continued research and drug development, treatment for those infected with HIV has evolved from multi-pill regimens to single-pill regimens,” said Edward Cox, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research. “New combination HIV drugs like Stribild help simplify treatment regimens.” The new pill, previously called Quad, is made by Gilead Sciences in California and “should be available to patients by the end of the week,” company spokeswoman Erin Rau told AFP.