Fiacitabine(NSC 382097; FIAC; FOAC) is a selective inhibitior of DNA replication of herpes simplex virus(HSV) with IC50 values of 2.5 nM and 12.6 nM for HSV1 and HSV2, respectively. IC50 value: 2.5/12.6 nM (HSV1/2) [2]Target: HSVFIAC suppressed by 90% the replication of various strains of herpes simplex virus types 1 and 2 at concentrations of 0.0025 to 0.0126 microM. Cytotoxicity was minimal, as determined by trypan blue dye exclusion with norman Vero, WI-38, and NC-37 cell proliferation; the 50% inhibitory dose was 4 to 10 microM in a 4-day assay. FIAC was active at much lower concentrations than arabinosylcytosine, iododeoxyuridine, and arabinosyladenine. It was slightly more active against herpes simplex virus type 1 than acycloquanosine and slightly more toxic to normal cells. FIAC was about 8,000 times more active against the replication of wild-type herpes simplex virus type 1 than against a mutant strain lacking the expression of virus-specified thymidine kinase [2].

[1]. Allaudeen HS, et al. Selective inhibition of DNA replication in herpes simplex virus infected cells by 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-iodocytosine. J Biol Chem. 1982 Oct 25;257(20):11879-82. [2]. Lopez C, et al. 2'-fluoro-5-iodo-aracytosine, a potent and selective anti-herpesvirus agent. Antimicrob Agents Chemother. 1980 May;17(5):803-6.