Assessment trials of the therapeutic efficacy of the drug "Zovirax" in some recurrent ocular and genital herpetic infections.

Abstract

In this work are reported the results of the researches performed by the authors more than a decade ago, aimed at assessing the clinical benefit of the introduction of the drug "Zovirax" in the treatment of recurrent herpetic infections with genital or ocular location. The results of the treatment carried out on a restricted group of patients were positive both in cases of genital herpes and of herpetic keratitis. The clinical benefit consisted in the reduction of the mean duration of the disease, in the shortening of the period of the infective virus elimination from the lesion, as well as in the decrease of the intensity and duration of the clinical symptomatology as a whole. With respect to these clinical parameters, the observations of the authors performed on a low number of cases are consistent with the data obtained by other authors in the framework of more extensive studies. The renewed discussion of these clinical and laboratory observations carried out by the authors during the first years after the introduction in our country of this drug in the therapeutic arsenal of herpetic infections is aimed at establishing a landmark for the comparison with more recent results of similar studies, starting from the idea of the opportunity of assessing periodically the sensitivity of herpes simplex virus strains, circulating among the autochthonous population, to the inhibitory action of some antiviral drugs. In other words, the in vitro testing of the susceptibility of these strains to the chemotherapeutic agents in current use is predictive for the efficacy degree of these drugs in the treatment of some forms of herpetic infections. This evaluation represents at the same time, undoubtedly, a useful epidemiological surveillance means of the circulation of human herpes viruses among the population. We refer especially to the risk of appearance of pharmacoresistant mutants, a risk possible under the conditions of the increased access of patients to the antiviral chemotherapeutic medication, which implicitly augments the probability of a fortuitous administration of treatments insufficient as regards the dose or the duration. In this work there are also shown the results regarding some experimental aspects related to the immune control mechanisms of the herpetic infection, which may complement the chemotherapeutic action. Under the treatment with acycloguanosine the synthesis of herpetic antigens is kept at a level sufficient for the circulating antibody synthesis induction and the HSV infected cells treated with the drug are recognized and lysed by effectors of the cell-mediated immune response of the host. Hence, it may be asserted that, in some clinical cases of recurrent herpes with frequent episodes, it is useful to perform immunostimulating treatments, able to potentiate the cell-mediated immune mechanisms possibly involved in the limitation of the herpetic infection at the peripheral level and of its spreading in the central nervous system.