Gilead Sciences Inc. said Wednesday its experimental four-drug HIV regimen is working as well as its current drug cocktail in a mid-stage clinical trial.

Gilead said the regimen of two experimental drugs called elvitegravir and GS 9350, as well as the combination drug Truvada, is meeting its main goal in the study. The combination was about as effective at reducing virus levels as Gilead's drug Atripla, which contains three medications.

The trial is scheduled to last 48 weeks, and Gilead said the "Quad" regimen met its goal at 24 weeks of treatment. The drugs are being tested on 71 people with HIV who have not taken another anti-retroviral treatment.

Elvitegravir is an integrase inhibitor, meaning it blocks the enzyme integrase, which the is one of the types of enzymes the AIDS virus uses to reproduce and infect cells. GS 9350 is designed to boost blood levels of medicines like elvitegravir.

Truvada made up of emtricitabine and tenofovir, and Atripla consists of those two drugs plus a third, efavirenz. Those drugs have already been approved by the Food and Drug Administration.

Gilead said full results from the study will be submitted for presentation at a scientific meeting in the next few months.

In morning trading, Gilead shares rose $1.49, or 3.4 percent, to $44.75.