Valnivudine (FV-100 free base), a prodrug of CF-1743, is an orally active anti-herpes zoster (HZ) nucleoside analogue. CF-1743, a bicyclic nucleoside analog (BCNA), has highly specific antiviral activity against varicella-zoster virus (VZV). Valnivudine is rapidly and extensively converted to CF-1743 in vivo[2].In Vitro: In vitro cytotoxicity studies in normal human primary hepatocytes, keratinocytes, and rapidly dividing HepG2 cells, Valnivudine (FV-100 free base) demonstrates mean 50% cytotoxic concentration values of >10 μM[2].
CF-1743 (compound 4f) has anti-varicella-zoster virus (VZV) activity in VZV OKA (EC50=0.3 nM), VZV YS (EC50=0.1 nM) in HEL cell.