A Phase III study evaluating Gilead Sciences’ HIV-1 candidate elvitegravir met its primary endpoint of noninferiority compared with raltegravir. Results showed that 59% of patients in the elvitegravir arm and 57.8% of raltegravir patients achieved and maintained a viral load of less than 50 copies/ml through week 48.
Study 145 was designed as a 48-week trial comparing the oral integrase inhibitor administered once-daily with raltegravir given twice-daily alongside a background treatment regimen including a ritonavir-boosted protease inhibitor and a second antiretroviral agent.
The study design was amended in January to increase the randomization period to 96 weeks to gather longer-term safety and efficacy data. Gilead says as a result of the 48-week data now reported, patients will continue on their designated blinded treatment regimens during the extension.
Elvitegravir is one of the four drugs in Gilead’s Phase III-stage Quad therapy, which is in development as a single pill combining fixed doses of elvitegravir, cobicistat, and the emtricitabine-tenofovir combination Truvada®. Cobicistat is a pharmacoenhancing agent designed to increase blood levels of certain HIV drugs. It is separately being evaluated as a stand-along boosting agent for other antiretrovirals and in particular protease inhibitors.
The latest data from Study 145 will be used to support regulatory filings for elvitegravir and the Quad pill, notes Norbert Bischofberger, Ph.D., Gilead’s CSO and vp for R&D. “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.”