Pritelivir (BAY 57-1293) is a potent helicase primase inhibitor, exhibiting antiviral effect on herpes simplex virus (HSV) with IC50 of 20 nM for both HSV-1 and HSV-2.
The mechanism of action is that BAY 57-1293 directly inhibits the ATPase activity of the viral helicase-primase enzyme complex in a dose-dependent manner. BAY 57-1293 also shows potent antiviral activity against acyclovir resistant HSV mutants.  BAY 57-1293 reduces Aβ and P-tau induced by herpes simplex virus type 1 in vero cells. 
BAY 57-1293 (p.o.) shows profound antiviral activity in murine and rat lethal challenge models of disseminated herpes (0.5 mg/kg), in a murine zosteriform spread model of cutaneous disease (15 mg/kg), and in a murine ocular herpes model.