Phase II clinical trial of Gilead Sciences' elvitegravir, GS 9350 and Truvada meets primary objective

Gilead Sciences, Inc. (Nasdaq:GILD) today announced that a Phase II clinical trial of its investigational integrase inhibitor-based, once-daily, fixed-dose “Quad” regimen of elvitegravir, GS 9350 and Truvada^® (emtricitabine and tenofovir disoproxil fumarate) for the treatment of HIV-1 infection met its primary objective. The ongoing study of 71 HIV-infected, antiretroviral treatment-naïve adults compares the Quad with Atripla^® (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg). Based on 24-week data, efficacy of the Quad met the statistical criteria of non-inferiority as compared to Atripla based on the proportion of subjects with HIV RNA levels (viral load) of less than 50 copies/mL. Discontinuation rates due to adverse events were comparable in both arms of the study. Full study results will be submitted for presentation at a scientific meeting in early 2010.

Elvitegravir is Gilead’s investigational HIV integrase inhibitor. GS 9350 is Gilead’s investigational pharmacoenhancing or “boosting” agent, being developed to increase blood levels of certain medicines, including elvitegravir, and allows for once-daily dosing.

Gilead is also studying GS 9350 as a stand-alone boosting agent for other antiretrovirals, in particular, protease inhibitors. A Phase II clinical trial evaluating the safety and efficacy of GS 9350-boosted atazanavir compared to ritonavir-boosted atazanavir, each in combination with Truvada, is ongoing. The Phase II study involves 79 HIV-infected, antiretroviral treatment-naïve adults. The study met its primary objective of achieving HIV RNA levels (viral load) of less than 50 copies/mL at 24 weeks of treatment. GS 9350-boosted atazanavir and Truvada had similar efficacy to ritonavir-boosted atazanavir and Truvada. Discontinuation rates due to adverse events were comparable in both arms of the study. Ritonavir is currently the only agent used to boost HIV therapy. Results from this study will also be submitted for presentation at a scientific meeting in early 2010.