Patients receive indinavir and ritonavir twice daily plus 2 NRTIs (NRTIs are not provided by this study). Physical examinations and laboratory tests, including plasma viral RNA levels and CD4 cell counts, are performed at Day 1 and Weeks 4, 8, 12, 16, 20, and 24 (or at discontinuation). The incidence of serious and drug-related adverse experiences is tabulated to determine drug safety. The proportion of patients achieving plasma viral RNA levels below 50 copies/ml (by UltraSensitive assay) are estimated statistically to determine drug efficacy.