N-Methanocarbathymidine is more effective than acyclovir for treating neonatal herpes simplex virus infection in guinea pigs.

The outcome of neonatal herpes simplex (HSV) infection, even after therapy with high dose acyclovir (ACV), is not optimum. We therefore evaluated N-Methanocarbathymidine ((N)-MCT) using the guinea pig model of neonatal herpes. Treatment with ACV (60 mg/kg/day) was compared to doses of 1, 5, and 25 mg/kg/day of (N)-MCT initiated 1, 2, or 3 days postinoculation (dpi). Both ACV and (N)-MCT significantly improved survival, but only (N)-MCT significantly reduced the number of animals with symptoms when begun at 1 dpi. When therapy was begun at 2 dpi, only (N)-MCT (1, 5, or 25 mg/kg/day) significantly increased survival. In fact, (N)-MCT improved survival up to 3 dpi, the last time point evaluated. (N)-MCT was highly effective and superior to high dose ACV therapy for the treatment of neonatal herpes in the guinea pig model.