Evaluation of Combinations of 4′-Ethynyl-2-Fluoro-2′-Deoxyadenosine with Clinically Used Antiretroviral Drugs

ABSTRACT Drug combination studies of 4′-ethynyl-2-fluoro-2′-deoxyadenosine (EFdA) with FDA-approved drugs were evaluated by two different methods, MacSynergy II and CalcuSyn. Most of the combinations, including the combination of the two adenosine analogs EFdA and tenofovir, were essentially additive, without substantial antagonism or synergism. The combination of EFdA and rilpivirine showed apparent synergism. These studies provide information that may be useful for the design of EFdA combination regimens for initial and salvage therapy assessment.