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 Monday.


The single daily dose of Stribild provides a complete treatment regimen for HIV infection, the US Food and Drug Administration said in a statement.

"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 regimen, made by Gilead Sciences in California, was tested in more than 1,400 patients, in two double-blind clinical trials.

Results showed that Stribild performed as well or better than two other treatment combinations, and brought virus readings down to undetectable levels in around nine of 10 patients after 48 weeks.

The drug combines Truvada -- another Gilead offering approved in 2004, that combines emtricitabine and tenofovir disoproxil fumarate to fight an enzyme that HIV needs to replicate -- with elvitegravir, another enzyme-fighting drug, and cobicistat, which enhances the effects of elvitegravir.

The drug was tested in adult patients not previously treated for HIV. The FDA said further study is required to determine the drug's safety for women and children, how resistance may develop, and whether the drug interacts with other drugs.