Gilead’s Phase II trial of its investigational integrase inhibitor-based, once-daily, fixed-dose “Quad” regimen of GS 9350, elvitegravir and Truvada (emtricitabine and tenofovir disoproxil fumarate) for the treatment of HIV-1, 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 regimen met the statistical criteria of non-inferiority 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 available in early this year.

Elvitegravir is Gilead’s investigational HIV integrase inhibitor and GS 9350 is an investigational “boosting” agent designed to increase blood levels of certain medicines, 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 trial evaluating the safety and efficacy of GS 9350-boosted atazanavir compared to ritonavir-boosted atazanavir, each in combination with Truvada, is ongoing. Results from this study will also be available early this year.