Gilead Sciences, Inc. (Nasdaq: GILD) today announced two-year Phase 3 clinical trial results showing that the integrase inhibitor elvitegravir dosed once daily is non-inferior to raltegravir dosed twice daily among treatment-experienced HIV patients. These findings will be presented today in an oral session (abstract #TUAB0105) at the 19th International AIDS Conference (AIDS 2012) in Washington, D.C. “As patients are living with HIV longer, there is a continued need for new treatment options – particularly those that are effective against strains of the virus that have developed resistance to currently available therapies,” said Richard Elion, MD, Clinical Research Director, Whitman-Walker Health, and principal investigator of the study. “In this study, elvitegravir demonstrated similar efficacy and tolerability as raltegravir among a difficult-to-treat patient population.” In the trial (Study 145), patients received elvitegravir or raltegravir, each with a background regimen that included a ritonavir-boosted protease inhibitor and another antiretroviral. At 96 weeks of treatment, 48 percent of elvitegravir patients compared to 45 percent of raltegravir patients achieved and maintained HIV RNA (viral load) levels less than 50 copies/mL, based on the U.S. Food and Drug Administration (FDA) Time to Loss of Virologic Response (TLOVR) algorithm (Intent-to-Treat (ITT) population; 95 percent CI for the difference: -4.6 percent to +9.9 percent; predefined criterion for non-inferiority was the lower bound of a two -sided 95 percent CI of -10 percent). Rates of adverse events, discontinuations due to adverse events and development of resistance were similar for elvitegravir and raltegravir, though Grade 2-4 diarrhea was more frequent among elvitegravir patients (13 percent) than raltegravir patients (8 percent) (p=0.02). On June 27, 2012, Gilead submitted a marketing application to FDA for elvitegravir. Elvitegravir is also under regulatory review by the European Medicines Agency. Topline 96-week results from Study 145 were announced on December 9, 2011. About Study 145 Study 145 is a randomized (1:1), double-blind, double-dummy, active-controlled Phase 3 clinical trial comparing the efficacy and safety of elvitegravir (n=354) versus raltegravir (n=358), each administered with a ritonavir-boosted background regimen. Eligible participants were HIV-infected treatment-experienced patients with HIV RNA (viral load) of greater than or equal to 1,000 copies/mL and were required to have documented viral resistance and/or at least six months of treatment experience with two or more different classes of antiretrovirals prior to enrollment.