A-5021: a new acyclovir analogue inhibits murine herpetic keratitis.

PURPOSE: To determine the efficacy of A-5021, a new analogue of acyclovir, on murine herpetic keratitis. METHODS: Herpes simplex virus type 1 (strain CHR3) was inoculated onto bilateral scarified BALB/c corneas. Clinical scores on the corneas treated with A-5021 eyedrops were compared with those obtained from the treatment with 3% acyclovir eye ointment by slit lamp microscopy. Virus titers of the trigeminal ganglia and eyeballs were quantitated on Vero cell monolayers. Mice treated with saline or a white petroleum jelly were used as controls. RESULTS: A-5021 eyedrops significantly suppressed both corneal epithelial and stromal lesions at all concentrations used. Clinical scores on the epithelium and stroma treated with 0.1% A-5021 were equivalent to those with 3% acyclovir treatment. When compared with the non-drug-treated control mice, virus titers in the eyeballs and trigeminal ganglia in A-5021- and acyclovir-treated mice were significantly less than those in controls. CONCLUSIONS: A-5021 eyedrops, which are easily applied onto the affected cornea, ameliorated clinical scores and suppressed virus growth. It is a promising alternative treatment of herpetic keratitis.