Comparison of antiretroviral activities of FA-P407-ATV/r and P407-ATV/r in hu-PBL reconstituted NSG mice infected with HIV-1ADA. Mice were treated on day 0 with PBS (untreated), free drug ATV/r, P407-ATV/r or FA-P407-ATV/r at doses of (A) 100 mg/kg or (B) 50 mg/kg. Mice were then infected with HIV-1ADA 24 hours later and sacrificed on day 14. HIV-1gag RNA expression in spleen was determined and normalized to human CD45 expression as a marker for human cell reconstitution. Data are expressed as mean ± SEM and considered *, ** statistically different, at P < 0.05 and P < 0.01, by the Mann-Whitney U-test.