Shares in Gilead Sciences closed up 2.3% at $60.78 on the Nasdaq yesterday, on news that the US Food and Drug Administration has granted traditional approval to the group’s HIV therapies Viread and Truvada.

Viread (tenofovir) and Truvada (emtricitabine plus tenefovir) were given accelerated approval in 2001 and 2004, respectively, but full clearance will now allow Gilead to add long-term study data to the products’ labels.

Results from a 48-week study indicate that Gilead's Emtriva (emtricitabine) and Viread, which are combined in Truvada, worked better and with fewer side effects as a treatment for HIV than GlaxoSmithKline’s Combivir, information which the group will likely use to try and increase sales of its drugs.

Gilead also announced its intention to file an application with the FDA for a combination of Truvada and Bristol-Myers Squibb’s Sustiva (efavirenz) in the second quarter. The first bid to develop the triple therapy pill failed last year when the Sustiva component did not achieve the same medication level in the blood compared to a dose of B-MS' drug given alone, forcing the firms back to the drawing board to design a new formulation of the treatment.