Reverse transcriptase foscamet

Foscamet (Foscavir) is an inorganic pyrophosphate analogue that acts in vitro against HSV-1, HSV-2, VZV, CMV, EB V HBV, and HIV. It acts as a noncompetitive inhibitor of viral DNA polymerase and reverse transcriptase by reversibly binding to the pyrophosphate-binding site of the viral enzyme and preventing the cleavage of pyrophosphate from deoxynucleoside triphosphates. 

Mellors JW, Bazmi HZ, Schinazi RF, Roy BM, Hsiou Y, Arnold E, et al. Novel mutations in reverse transcriptase of human immunodeficiency virus type 1 reduce susceptibility to foscamet in laboratory and clinical isolates. Antimicrob Agents Chemother 1995 39 1087-1092. 

Foscamet (4) is an inorganic pyrophosphate derivative that inhibits viral DNA, RNA polymerases and HIV reverse transcriptase (RT) directly without the need of any activation steps. It is in vitro active against HSV, VZV, CMV, EBV, HHV-6, HBV and HIV. Resistance is developed due to mutation in Ae DNA polymerase gene [13]. 

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