Simultaneous vs sequential initiation of therapy with indinavir, zidovudine, and lamivudine for HIV-1 infection - 100-week follow-up

Context.-Combination antiretroviral therapy can markedly suppress human immunodeficiency virus (HIV) replication but the duration of HIV suppression varies among patients. Objective.-To compare the antiretroviral effect of a 3-drug regimen started simultaneously or sequentially in patients with HIV infection, Design.-A multicenter, randomized, double-blind study, modified after at least 24 weeks of blinded therapy to provide open-label 3-drug therapy with follow-up through 100 weeks. Setting.-Four clinical research units Patients.-Ninety-seven patients with HIV infection who had taken zidovudine for at least 6 months with serum HIV RNA level of at least 20 000 copies/mL and CD4 cell count of 0.05 to 0.40 x 10(9)/L, Interventions.-Patients were initially randomized to receive 1 of 3 antiretroviral regimens: indinavir, 800 mg every 8 hours; zidovudine, 200 mg every 8 hours and lamivudine, 150 mg every 12 hours; or all 3 drugs. After at least 24 weeks of blinded therapy, all patients received open-label 3-drug therapy. Main Outcome Measures.-Anti retroviral activity was assessed by changes in HIV RNA level and CD4 cell count from baseline. Data through 100 weeks were summarized. Results.-Simultaneous initiation of indinavir, zidovudine, and lamivudine suppressed HIV RNA in 78% (25/32) of contributing patients to less than 500 copies/ mi and increased CD4 cell count to a median of 0.209 x 10(9)/L above baseline at 100 weeks. When these 3 drugs were initiated sequentially, only 30% to 45% of contributing patients (10 of 33 in the zidovudine-lamivudine group and 13 of 29 in the indinavir group, respectively) had a sustained reduction in H(V RNA to less than 500 copies/mL, and median CD4 cell count increased to 0.101 to 0.163 x 10(9)/L above baseline at 100 weeks. Conclusions.-A 3-drug combination of indinavir, zidovudine, and lamivudine, started simultaneously has durable antiretroviral activity for at least 2 years. Sequential initiation of the same 3 drugs is much less effective.