In September 2012, Stribild was added to U.S. Department of Health and Human Services (DHHS) guidelines as an “alternative” treatment regimen for patients new to HIV therapy. Atripla and ritonavir-boosted atazanavir plus Truvada are both listed as “preferred” first-line regimens in the guidelines. Stribild has a Boxed Warning of lactic acidosis/severe hepatomegaly with steatosis and post treatment acute exacerbation of hepatitis B; see below for important safety information.
Gilead recently initiated WAVES, a Phase 3b study evaluating Stribild compared to ritonavir-boosted atazanavir plus Truvada among more than 500 HIV-positive treatment-naïve women. Additional studies examining the efficacy and safety of switching treatment-experienced virologically suppressed patients to Stribild are also underway.
Study 102 is a randomized (1:1), double-blind Phase 3 clinical trial comparing the efficacy, safety and tolerability of Stribild (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) (n=348) versus Atripla (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) (n=352) among HIV-infected treatment-naïve adults with HIV RNA levels greater than or equal to 5,000 copies/mL. The primary endpoint of the study is the proportion of patients achieving HIV RNA levels < 50 copies/mL at 48 weeks of treatment, per the FDA snapshot algorithm. Secondary objectives will evaluate the efficacy, safety and tolerability of the treatment regimens through 192 weeks of treatment.At baseline, patients in the Stribild arm had a median HIV RNA of 4.75 log 10 copies/mL and mean CD4 cell count of 391 cells/mm 3. Patients in the Atripla arm had a median HIV RNA of 4.78 log 10 copies/mL and mean CD4 cell count of 382 cells/mm 3. Across both arms, 33 percent of patients had HIV RNA > 100,000 copies/mL, and 13 percent of patients had CD4 counts ≤ 200 cells/mm 3. At 96 weeks, mean increases in CD4 cell counts were 295 cells/mm 3 for Stribild patients and 273 cells/mm 3 for Atripla patients (p=0.19). Virologic failure rates were 6 percent for Stribild compared to 8 percent for Atripla. Five percent of Stribild patients and 7 percent of Atripla patients discontinued treatment due to adverse events. The most common adverse events leading to treatment discontinuation among patients taking Stribild were renal events, depression and fatigue. Between 48 and 96 weeks of treatment, two Stribild patients discontinued due to serum creatinine increase without features of proximal renal tubulopathy, and both patients improved after treatment discontinuation.