Open-label study of a twice-daily indinavir 800-mg/ritonavir 100-mg regimen in protease inhibitor-naive HIV-infected adults

Low-dose ritonavir can boost plasma levels of indinavir, thereby enhancing its antiretroviral activity despite less frequent dosing. In this open-label, noncomparative, 24-week trial with a 24-week extension phase, HIV-infected protease inhibitor (PI)- and lamivudine-naive adults received indinavir/ritonavir 800 mg/100 mg plus stavudine and lamivudine every 12 hours. The proportions of patients achieving plasma HIV RNA (vRNA) <400 and <50 copies/mL were analyzed with data as observed (DAO) and intention-to-treat models using generalized estimating equations (GEE) or counting noncompleters as failures (NC = F). Eighty-nine patients (80% men) with a median age of 36 years and mean baseline vRNA levels and CD4 counts of 5.01 log(10) copies/mL and 269 celIs/mm(3) were enrolled. The proportions (95% confidence interval [CI]) of patients achieving vRNA <400 copies/mL were 93% (84%, 98%), 78% (67%, 86%), and 68% (57%, 78%) at week 24 for DAO, GEE, and NC = F analyses, respectively; the corresponding results at week 48 were 95% (84%, 99%), 65% (53%, 76%), and 45% (35%, 57%). Most patients with vRNA <400 had <50 copies/mL. At week 48, baseline vRNA decreased by >2 log(10) copies/mL and CD4 counts increased by approximately 200 cell/mm(3). Five patients (6%) experienced serious drug-related adverse experiences. Twenty patients (23%) discontinued therapy due to adverse experiences. In this study, twice-daily indinavir 800 mg/ritonavir 100 mg with two nucleoside reverse transcriptase inhibitors provided potent viral suppression and immunologic reconstitution in many PI-naive patients.