A randomized controlled trial of single‐class maintenance therapy with abacavir/lamivudine/zidovudine after standard triple antiretroviral induction therapy: final 96‐week results from the FREE study

Objectives The aim of the study was to test the antiviral efficacy of a triple nucleoside reverse transcriptase inhibitor ( NRTI ) regimen, with potential beneficial metabolic effects, as maintenance therapy after induction with dual NRTIs and a boosted protease inhibitor ( PI ). Methods An open‐label, noninferiority study was carried out. Antiretroviral therapy ( ART )‐naïve patients with CD 4 count ≤ 350 cells/μL and HIV ‐1 RNA > 30 000 copies/mL ( n  = 207) were treated with zidovudine/lamivudine and lopinavir/ritonavir. After achieving HIV ‐1 RNA < 50 copies/mL on two consecutive occasions between weeks 12 and 24 after baseline, 120 patients (baseline: median HIV ‐1 RNA 5.19 log 10 copies/mL; median CD 4 count 180 cells/μL) were randomized to receive abacavir/lamivudine/zidovudine ( ABC /3 TC / ZDV ) ( n  = 61) or to continue the PI ‐based ART ( n  = 59). Results For the proportions of patients (intention‐to‐treat; missing = failure) with HIV ‐1 RNA < 400 copies/mL ( PI group, 66%; ABC /3 TC / ZDV group, 71%) and < 50 copies/mL ( PI group, 63%; ABC /3 TC / ZDV group, 62%) at 96 weeks, switching to ABC /3 TC / ZDV was noninferior compared with continuing the PI regimen; the difference in failure rate ( ABC /3 TC / ZDV minus PI ) was −4.4 percentage points [95% confidence interval ( CI ) −21.0 to +12.3 percentage points] and +0.4 percentage points (95% CI −16.9 to +17.7 percentage points), respectively. In the per protocol analysis, the difference in virological failure for HIV ‐1 RNA > 400 copies/mL (0 of 39 patients in the PI group and two of 45 patients in the NRTI group) and for HIV ‐1 RNA > 50 copies/mL (two of 39 and three of 45 patients, respectively) was +4.4 percentage points (95% CI −2.1 to +11.0 percentage points) and +1.5 percentage points (95% CI −8.6 to +11.7 percentage points), respectively, also showing noninferiority. Serum lipids significantly improved in the NRTI group, but not in the PI arm.Conclusions A single‐class NRTI regimen after successful induction with standard ART had similar antiviral efficacy compared to continuation of a PI ‐based regimen at 96 weeks after baseline, with improved serum lipids.