Preclinical Safety Evaluation of Oncolytic Herpes Simplex Virus Type 2.

Oncolytic virotherapy is a new and safe therapeutic strategy based on the inherent cytotoxicity of oncolytic viruses and their ability to replicate and spread within tumors in a selective manner. In a previous study, a new type of oncolytic herpes simplex virus type 2 (oHSV-2, named OH2) was constructed to treat human cancers. That study demonstrated that OH2 is genetically and biologically stable. Its antitumor activity was maintained, even after passaging the virus for >20 generations. To advance OH2 into a clinical trial, a systematic preclinical safety evaluation was performed, which included: an acute toxicity test of OH2 in BALB/c mice; repeated dose toxicity tests of OH2 in BALB/c mice and cynomolgus monkeys; and biodistribution assays of OH2 in BALB/c mice, tumor-bearing mice, tumor-bearing nude mice, and cynomolgus monkeys. The results of this preclinical safety evaluation of OH2 indicate that OH2 is safe and suitable for clinical trials.