bay-57-1293 and Disease-Models--Animal

Pritelivir, a helicase-primase inhibitor, has excellent in vitro and in vivo activity against human herpes simplex virus (HSV). Mice lethally infected with HSV type 1 or 2, including acyclovir-resistant strains, were treated 72 h after infection for 7 days with pritelivir or acyclovir. Both drugs were administered orally twice daily either alone or in combination. Dosages of pritelivir from 0.3 to 30 mg/kg reduced mortality (P < 0.001) against HSV-1, E-377. With an acyclovir resistant HSV-1, 11360, pritelivir at 1 and 3 mg/kg increased survival (P < 0.005). With HSV-2, MS infected mice, all dosages higher than the 0.3 mg/kg dose of pritelivir were effective (P < 0.005). For acyclovir resistant HSV-2, strain 12247, pritelivir dosages of 1-3 mg/kg significantly improved survival (P < 0.0001). Combination therapies of pritelivir at 0.1 or 0.3 mg/kg/dose with acyclovir (10 mg/kg/dose) were protective (P < 0.0001) when compared to the vehicle treated group against HSV-2, strain MS (in line with previous data using HSV-1). An increased mean days to death (P < 0.05) was also observed and was indicative of a potential synergy. Pharmacokinetic studies were performed to determine pritelivir concentrations and a dose dependent relationship was found in both plasma and brain samples regardless of infection status or time of initiation of dosing. In summary, pritelivir was shown to be active when treatment was delayed to 72 h post viral inoculation and appeared to synergistically inhibit mortality in this model in combination with acyclovir. We conclude pritelivir has potent and resistance-breaking antiviral efficacy with potential for the treatment of potentially life-threatening HSV type 1 and 2 infections, including herpes simplex encephalitis.

Topics: Acyclovir; Animals; Antiviral Agents; Disease Models, Animal; Drug Therapy, Combination; Encephalitis, Herpes Simplex; Female; Humans; Mice; Pyridines; Sulfonamides; Thiazoles; Tissue Distribution; Treatment Outcome

BAY 57-1293 represents a new class of potent inhibitors of herpes simplex virus (HSV) that target the virus helicase primase complex. The present study was conducted using the zosteriform infection model in BALB/c mice. The helicase primase inhibitor, BAY 57-1293 was shown to be highly efficacious in this model. The beneficial effects of therapy were obtained rapidly (within 2 days) although the onset of treatment was delayed for 1 day after virus inoculation. The compound given orally, or intraperitoneally once per day at a dose of 15 mg/kg for 4 successive days was equally effective or superior to a much higher dose of famciclovir (1mg/ml, i.e. approximately 140-200mg/kg/day) given in the drinking water for 7 consecutive days, which, in our hands, is the most effective method for administering famciclovir to mice. In contrast to the vehicle-treated infected mice, all mice that received antiviral therapy looked normal and active with no mortality, no detectable loss of weight and no marked change in ear thickness. BAY 57-1293 and famciclovir reduced the virus titers in the skin to below the level of detection by days 3 and 7 post infection, respectively. In both BAY 57-1293 and famciclovir-treated mice, infectious virus titers in the ear pinna and brainstem remained below the level of detection. Consistent with these findings, BAY 57-1293 also showed a potent antiviral effect in an experiment involving a small number of severely immunocompromised athymic-nude BALB/c mice.

Topics: 2-Aminopurine; Administration, Oral; Animals; Antiviral Agents; Brain Stem; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Ear; Famciclovir; Herpes Simplex; Herpesvirus 1, Human; Injections, Intraperitoneal; Mice; Mice, Inbred BALB C; Mice, Nude; Pyridines; Skin; Sulfonamides; Thiazoles

The efficacy of BAY 57-1293, a novel non-nucleosidic inhibitor of herpes simplex virus 1 and 2 (HSV-1 and HSV-2), bovine herpesvirus and pseudorabies virus, was studied in the guinea pig model of genital herpes in comparison with the licensed drug valaciclovir (Valtrex). Early therapy with BAY 57-1293 almost completely suppressed the symptoms of acute HSV-2 infection, and reduced virus shedding and viral load in the sacral dorsal root ganglia by up to three orders of magnitude, resulting in decreased latency and a greatly diminished frequency of subsequent recurrent episodes. In contrast, valaciclovir showed only moderate effects in this set of experiments. When treatment was initiated late during the course of disease after symptoms were apparent, that is, a setting closer to most clinical situations, the efficacy of therapy with BAY 57-1293 was even more pronounced. Compared with valaciclovir, BAY 57-1293 halved the time necessary for complete healing. Moreover, the onset of action was fast, so that only very few animals developed new lesions after treatment commenced. Finally, in a study addressing the treatment of recurrent disease in animals whose primary infection had remained untreated BAY 57-1293 was efficient in suppressing the episodes. In summary, superior potency and efficacy of BAY 57-1293 over standard treatment with valaciclovir was demonstrated in relevant animal models of human genital herpes disease in terms of abrogating an HSV infection, reducing latency and the frequency of subsequent recurrences. Furthermore, BAY 57-1293 shortens the time to healing even if initiation of therapy is delayed.

Topics: Animals; Antiviral Agents; Disease Models, Animal; DNA Helicases; DNA Primase; DNA, Viral; Enzyme Inhibitors; Guinea Pigs; Herpes Genitalis; Herpesvirus 2, Human; Humans; Polymerase Chain Reaction; Pyridines; Sulfonamides; Thiazoles