Gilead Sciences, a biopharmaceutical company, has started enrolling patients in a Phase II clinical trial of its investigational integrase-based, single-tablet, once-daily regimen of elvitegravir, GS 9350 and Truvada for the treatment of HIV-1 infection.
The Phase II study is a randomized, double-blind, 48-week clinical trial that will evaluate the safety and efficacy of a single-tablet containing elvitegravir, GS 9350 and Truvada versus Atripla, each administered in HIV-infected treatment-naive adults with HIV RNA levels (viral load) greater than or equal to 5,000 copies/mL and CD4 cell counts greater than 50 cells/cubic millimeter.
A total of 75 trial participants will be randomized (2:1) to receive a once-daily tablet containing elvitegravir 150mg/GS 9350 150mg/emtricitabine 200mg/tenofovir disoproxil fumarate 300mg (n=50) or Atripla (efavirenz 600mg/emtricitabine 200mg/tenofovir disoproxil fumarate 300mg) (n=25).
The primary endpoint will be the proportion of patients with viral loads less than 50 copies/mL at 24 weeks of treatment. Secondary endpoints will include the proportion of patients with viral loads less than 50 copies/mL at 48 weeks of treatment, and the safety and tolerability of the two treatment regimens through 48 weeks of treatment.
After week 48, subjects will continue to take their blinded study drug until treatment assignments have been unblinded, at which point all subjects will be given the option to participate in an open-label rollover extension and receive the single-tablet regimen containing elvitegravir, GS 9350 and Truvada.
Gilead is also examining GS 9350 as a stand-alone boosting agent for other antiretrovirals, in particular, protease inhibitors. Later this quarter, Gilead also plans to initiate 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. Ritonavir is currently reported to be the only boosting agent available for HIV therapy.
Norbert Bischofberger, executive vice president of R&D and chief scientific officer at Gilead Sciences, said: The initiation of this Phase II study is an important milestone in the development of our integrase-based, single-tablet, once-daily regimen for HIV. The single-dose regimen of Atripla has become the standard of care for many patients, particularly those new to therapy. If proven safe and effective, this new single-tablet regimen has the potential to provide an important alternative for them.