Current status of clinical trials assessing oncolytic virus therapy for urological cancers.

Oncolytic virus therapy has recently been recognized as a promising new option for cancer treatment. Oncolytic viruses replicate selectively in cancer cells, thus killing them without harming normal cells. Notably, T-VEC (talimogene laherparepvec, formerly called OncoVEX ), an oncolytic herpes simplex virus type 1, was approved by the US Food and Drug Administration for the treatment of inoperable melanoma in October 2015, and was subsequently approved in Europe and Australia in 2016. The efficacies of many types of oncolytic viruses against urological cancers have been investigated in preclinical studies during the past decade, and some have already been tested in clinical trials. For example, a phase I trial of the third-generation oncolytic Herpes simplex virus type 1, G47Δ, in patients with prostate cancer was completed in 2016. We summarize the current status of clinical trials of oncolytic virus therapy in patients with the three major urological cancers: prostate, bladder and renal cell cancers. In addition to Herpes simplex virus type 1, adenoviruses, reoviruses, vaccinia virus, Sendai virus and Newcastle disease virus have also been used as parental viruses in these trials. We believe that oncolytic virus therapy is likely to become an important and major treatment option for urological cancers in the near future.