Median changes from baseline in total cholesterol, HDL (high-density lipoprotein or “good” cholesterol) and LDL at 96 weeks were, respectively, +9, +6 and +9 mg/dL for Stribild and +18, +8 and +16 mg/dL for Atripla (total cholesterol, p<0.001; HDL, p=0.008; LDL, p=0.011). The median change in triglycerides was +4 mg/dL for Stribild and +8 mg/dL for Atripla (p=0.41).
Study 103 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=353) versus atazanavir 300 mg boosted by ritonavir 100 mg plus Truvada (emtricitabine and tenofovir disoproxil fumarate) (n=355) among HIV-infected treatment-naïve adults with baseline HIV RNA levels > 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 4.88 log 10 copies/mL and mean CD4 cell count of 364 cells/mm 3. Patients in the atazanavir-based arm had a median HIV RNA of 4.86 log 10 copies/mL and mean CD4 cell count of 375 cells/mm 3. Across both arms, 41 percent of patients had HIV RNA > 100,000 copies/mL and 13 percent had CD4 counts ≤ to 200 cells/mm 3.At 96 weeks, patients in both arms experienced similar increases in CD4 cell counts (mean increase of 256 cells/mm 3 for Stribild and 261 cells/ mm 3 for the atazanavir-based regimen). The virologic failure rate was 7 percent for both treatment regimens. Five percent of Stribild patients and 6 percent of patients on the atazanavir-based regimen discontinued treatment due to adverse events. The most common adverse events leading to treatment discontinuation among patients taking Stribild were renal events, diarrhea, pyrexia, nausea, vomiting and fatigue. Between 48 and 96 weeks of treatment, one Stribild patient and one patient in the atazanavir-based regimen discontinued due to serum creatinine increase without features of proximal renal tubulopathy, and both patients improved after treatment discontinuation. Ocular icterus (associated with elevated bilirubin levels) was less common among Stribild patients (less than 1 percent) compared to patients taking the atazanavir-based regimen (14 percent).