Although dramatic inhibition of HIV-1 replication is achieved with ritonavir or indinavir monotherapy, in both cases maximum suppression required combination treatment together with nucleoside analog RT inhibitors. This study tests the hypothesis that monotherapy with 141W94 doses that result in Cmin levels far in excess of the IC90 corrected for plasma protein binding for HIV-1 can achieve the same virologic and immunologic effects in terms of magnitude and durability, as has been observed with combinations of other protease inhibitors plus nucleoside analogs.