Objective. ACTG A5230 evaluated lopinavir/ritonavir (LPV/r) monotherapy following virologic failure on first-line regimens in Africa and Asia.

Methods. Eligible subjects had received first-line regimens for at least 6 months and had plasma HIV-1 RNA levels 1000-200,000copies/mL. All subjects received LPV/r 400/100mg twice daily. Virologic failure (VF) was defined as failure to suppress to <400 copies/mL by week 24, or confirmed rebound to >400 copies/mL at or after week 16 following confirmed suppression. Subjects with VF added emtricitabine 200mg/tenofovir 300mg (FTC/TDF) once daily. The probability of continued HIV-1 RNA <400 copies/mL on LPV/r-monotherapy through week 104 was estimated with a 95% confidence interval (CI); predictors of treatment success were evaluated with Cox proportional hazards models.

Results. 123 subjects were enrolled. Four subjects died and 2 discontinued prematurely; 117 /123 (95%) completed 104 weeks. Through week 104, 49 subjects met the primary endpoint; 47 had VF, and 2 intensified treatment without VF. Of the 47 subjects with VF, 41 (33%) intensified treatment, and 39/41 subsequently achieved levels <400 copies/mL. The probability of continued suppression <400copies/mL over 104 weeks on LPV/r-monotherapy was 60% [95% CI 50%, 68%]; 80-85% maintained levels <400 copies/mL with FTC/TDF intensification as needed. Ultrasensitive assays on specimens with HIV-1 RNA level<400 copies/mL at weeks 24, 48 and 104 revealed that 61%, 62% and 65% were suppressed to <40 copies/mL, respectively.

Conclusion. LPV/r monotherapy after first-line virologic failure with FTC/TDF intensification when needed provides durable suppression of HIV-1 RNA over 104 weeks.