Background: Efavirenz is a nonnucleoside reverse-transcriptase inhibitor of human immunodeficiency virus type 1 (HIV-1). We compared two regimens containing efavirenz, one with a protease inhibitor and the other with two nucleoside reverse-transcriptase inhibitors, with a standard three-drug regimen.
Methods: The study subjects were 450 patients who had not previously been treated with lamivudine or any nonnucleoside reverse-transcriptase inhibitor or protease inhibitor. In this open-label study, patients were randomly assigned to one of three regimens: efavirenz (600 mg daily) plus zidovudine (300 mg twice daily) and lamivudine (150 mg twice daily); the protease inhibitor indinavir (800 mg every eight hours) plus zidovudine and lamivudine; or efavirenz plus indinavir (1000 mg every eight hours).
Results: Suppression of plasma HIV-1 RNA to undetectable levels was achieved in more patients in the group given efavirenz plus nucleoside reverse-transcriptase inhibitors than in the group given indinavir plus nucleoside reverse-transcriptase inhibitors (70 percent vs. 48 percent, P<0.001). The efficacy of the regimen of efavirenz plus indinavir was similar (53 percent) to that of the regimen of indinavir, zidovudine, and lamivudine. CD4 cell counts increased significantly with all combinations (range of increases, 180 to 201 cells per cubic millimeter). More patients discontinued treatment because of adverse events in the group given indinavir and two nucleoside reverse-transcriptase inhibitors than in the group given efavirenz and two nucleoside reverse-transcriptase inhibitors (43 percent vs. 27 percent, P=0.005).
Conclusions: As antiretroviral therapy in HIV-1-infected adults, the combination of efavirenz, zidovudine, and lamivudine has greater antiviral activity and is better tolerated than the combination of indinavir, zidovudine, and lamivudine.