Preclinical Safety Assessment of Antineoplastic Agents Based on Live Non-Pathogenic Enteroviruses

Abstract

INTRODUCTION. Developing novel medicines based on non-pathogenic enterovirus strains exhibiting oncotropic and oncolytic properties represents an up-to-date and safe approach to complex cancer treatment and postoperative metastasis prevention. Safety pharmacology studies are a necessary step in the preclinical development of medicinal products.AIM. The study aimed to investigate the single and repeated-dose general toxicity, local tolerance, safety pharmacology, and pyrogenicity of medicinal products based on non-pathogenic LEV4, LEV7, LEV8, LEV14, and Russo enterovirus strains as part of preclinical safety studies.MATERIALS AND METHODS. The study used medicinal products of highly purified group A, B, and C enteroviruses at a titre of 2×107–5×108 CPD50/mL (CPD50 is a cytopathogenic dose of the virus causing 50% cell lysis) and normal saline as a diluent. The viruses were propagated in Vero cells. The safety study used 220 male and female BALB/c mice, 440 male and female Wistar rats, and 18 male Soviet chinchilla rabbits. The study animals received an intravenous dose of 1×105 or 1×106 CPD50/animal once (single-dose toxicity) or weekly for 90 days (repeated-dose toxicity). Clinical examination, laboratory testing, and necropsy were performed on days 45 and 91 of the experiment. Statistical data processing was performed using Prism 8.0 software (GraphPad Software, Inc., USA).RESULTS. Upon single administration of each of the five enterovirus medicinal products to mice and rats, the authors observed complete survival, upward trends in body weight gain, and no gross or histopathological changes in the brain, spleen, liver, kidneys, lungs, or at the injection site. Upon repeated administration at the study doses, the medicinal products caused no functional changes in the organs and systems. All the studied parameters were within the normal physiological ranges for male and female rats. Histopathological examination revealed no pathological changes or specific cytolytic and/or cytopathic effects. No local irritation was observed. None of the investigational medicinal products showed pyrogenicity.CONCLUSIONS. The obtained preclinical results demonstrate the safety of antineoplastic agents based on live non-pathogenic LEV4, LEV7, LEV8, LEV14, and Russo enteroviruses.