Optimizing treatment switch for virologic failure during first-line antiretroviral therapy in resource-limited settings.

We evaluated adult Nigerian patients with antiretroviral switch to second-line treatment with ritonavir-boosted protease inhibitor (PI/r)-based regimens due to virologic failure (confirmed HIV-1 RNA viral load [VL] >1000 copies/mL) during first-line antiretroviral therapy. Proportion of patients with VL >400 copies/mL and characteristics associated with nonsuppression during second-line treatment are described. Approximately 15% of patients (34 of 225) had VL >400 copies/mL at 1-year after treatment switch to PI/r-based regimens. In adjusted analyses, VL ≥5 log10 copies/mL at treatment switch (odds ratio [OR] 2.90 [confidence interval (CI) 1.21-6.93]); duration of first-line treatment after virologic failure >180 days (OR 2.56 [CI 1.0-6.54]); and PI/r regimen adherence <90% (OR 3.27 [CI 1.39-7.68]) were associated with VL >400 copies/mL at 1 year of second-line treatment. We therefore recommend that the maximum permissible time between suspicion of virologic failure and completion of antiretroviral treatment switch should not exceed 6 months when patients develop first-line antiretroviral failure in resource-limited settings.