An HIV-1 protease inhibitor; inhibits replication of various laboratory strains and clinical isolates of HIV-1 (IC50s = 3-30 nM); non-cytotoxic to MT-2 cells (CC50 = >100 μM); inhibits cell-free diffusion and cell-to-cell spread of HIV-1 in Jurkat cell populations (IC50s = 2.5 and 2.8 nM, respectively)