MK-8591 (4′-ethynyl-2-fluoro-2′-deoxyadenosine) exhibits potent activity against HIV-2 isolates and drug-resistant HIV-2 mutants in culture

There is a pressing need to identify more effective antiretroviral drugs for HIV-2 treatment. Here, we show that the investigational compound MK-8591 (4′-ethynyl-2-fluoro-2′-deoxyadenosine [EFdA]) is highly active against group A and B isolates of HIV-2; 50% effective concentrations [EC50] for HIV-2 were, on average, 4.8-fold lower than those observed for HIV-1. MK-8591 also retains potent activity against multinucleoside-resistant HIV-2 mutants (EC50 ≤ 11 nM). These data suggest that MK-8591 may have antiviral activity in HIV-2-infected individuals.