Gilead Sciences, Inc. (Nasdaq:GILD) today announced that the Phase III clinical trial of its investigational antiretroviral agent elvitegravir, a novel oral integrase inhibitor being evaluated for the treatment of HIV-1 infection in treatment-experienced patients, met its primary objective. The primary endpoint of this study was non-inferiority at week 48 of elvitegravir, dosed once daily, compared to raltegravir, dosed twice daily, each administered with a background regimen that includes a ritonavir-boosted protease inhibitor (PI) and a second antiretroviral agent. Responses at 48 weeks of elvitegravir met the statistical criteria of non-inferiority as compared to raltegravir based on the proportion of subjects who achieved and maintained 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. Gilead plans to submit these data for presentation at a scientific conference later this year.
On January 10, 2011, Gilead announced an amendment to the design of this clinical trial, extending the blinded, randomized period of the study to up to 96 weeks to obtain longer term safety and efficacy data than originally planned. Based on the achievement of the non-inferiority endpoint, patients will continue to receive the regimen to which they were randomized in a blinded fashion.
Elvitegravir is also being studied as part of Gilead's investigational fixed-dose, single-tablet "Quad" regimen. The Quad contains four Gilead compounds in a fixed-dose, single-tablet: elvitegravir; cobicistat, a pharmacoenhancing or "boosting" agent that increases blood levels of certain HIV medicines; and Truvada® (emtricitabine/tenofovir disoproxil fumarate). The Quad is currently in Phase III testing. In addition, cobicistat is being evaluated as a stand-alone boosting agent for other antiretrovirals, in particular, protease inhibitors.
"We are very pleased to have achieved the primary endpoint in this clinical trial, as data from this study will support regulatory filings for elvitegravir as well as Gilead's investigational Quad pill," said Norbert Bischofberger, PhD, Executive Vice President, Research and Development and Chief Scientific Officer, Gilead Sciences. "By analyzing these data now we will be in a better position to advance filings as quickly as possible once data from subsequent Phase III clinical trials in our Quad development program become available later this year."
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