Effect of famciclovir on herpes simplex virus type 1 corneal disease and establishment of latency in rabbits

Alpha/Beta Interferon and Gamma Interferon Synergize To Inhibit the Replication of Herpes Simplex Virus Type 1

“…The potency with which IFN-␤ and IFN-␥ inhibited HSV-1 replication in vivo appeared to be considerably greater than is typically achieved when animals are treated with ACV or other antiviral agents in vivo (12,18,30,36,58). In mice pretreated with IFN-␤ and IFN-␥, HSV-1 replication was not detected in the eyes of six of the eight mice, and the average level of virus replication in the remaining two mice was ϳ500-fold less than observed in vehicle-treated controls.…”

Pharmacokinetics of famciclovir and penciclovir in tears following oral administration of famciclovir to cats: a pilot study

“…This observation may reflect the inability of a systemically administered medication to achieve therapeutic concentrations at the corneal surface or within the avascular corneal stroma. Although orally administered valacyclovir or famciclovir has been used to treat epithelial keratitis caused by HSV‐1 in humans and experimentally‐induced HSV‐1 infections in rabbits and mice, 14–16 to the authors’ knowledge the concentration of penciclovir required at the corneal surface for effective control of herpetic disease has not been reported in any species, including humans.…”

Recalcitrant Herpetic Epithelial Keratitis

“…Therapeutic doses of FCV improved SLE scores in rabbits acutely infected with HSV-1 and significantly reduced the genome copy number of HSV-1 in the TG of latently infected rabbits [10]. In addition, during an episode of recurrent keratitis, FCV decreases the amount of acute virus in the TG by diminishing the development of new latent foci, resulting in an appealing option, if ACV resistance is suspected, with the advantage of reducing corneal morbidity in patients with recurrent HSK [10]. Moreover, its lower frequency of administration may improve adherence to medication.…”

“…FCV, the oral prodrug of penciclovir, has an active triphosphate form that persists in infected cells longer and has more oral bioavailability than ACV [6]. Therapeutic doses of FCV improved SLE scores in rabbits acutely infected with HSV-1 and significantly reduced the genome copy number of HSV-1 in the TG of latently infected rabbits [10]. In addition, during an episode of recurrent keratitis, FCV decreases the amount of acute virus in the TG by diminishing the development of new latent foci, resulting in an appealing option, if ACV resistance is suspected, with the advantage of reducing corneal morbidity in patients with recurrent HSK [10].…”