New Generation of Oncolytic Herpes Virus

Oncolytic virus therapy has recently been recognized as a promising new treatment option for cancer. The strategy is to use genetically engineered or naturally occurring viruses that selectively replicate in and kill cancer cells, without harming normal cells. Herpes simplex virus type 1 (HSV-1) has been well studied and has many advantages for the use in cancer therapy, making it the mainstay of current clinical trials of oncolytic virus therapy. Numerous preclinical and clinical studies of oncolytic HSV-1 have demonstrated its safety and antitumor efficacy, the latter of which is mainly attributable to its direct cytocidal effect. However, recent studies have also suggested that oncolytic HSV-1 elicits host antitumor immunity and induces immunogenic cancer cell death, thus offering possibilities for multifaceted strategies by focusing on enhancement of host anticancer immunity. In this review, we summarize the history and current status of preclinical and clinical studies of oncolytic virus therapy using HSV-1.