Oncolytic virotherapy is cancer treatment using a virus that has the potential to halt the uncontrolled growth or even destroy cancer cells.
The earliest scientific publication with the word “virotherapy” in the title or abstract that can today be found in PubMed dates from 1960. This is the time when the screening of viruses in preclinical models of cancer was started that led to the development of Rigvir. Several decades later the interest in virotherapy increased once again. A listing reached close to 100 recent and ongoing virotherapy clinical trials run by industry and well known universities and academia. The tested viruses include Herpes Simplex as well as polio virus. The therapeutic areas include melanoma, glioma, colorectal and prostate cancer.
There are three main types of immunotherapy; active, passive and indirect. Oncolytic virotherapy is a specific active immunotherapy. There is a slight overlap, since oncolytic viruses are often also immunomodulators, which constitute the nonspecific part of active immunotherapy. In addition, oncolytic viruses are oncotropic, selectively targeting cancers cells.
Virotherapy targets cancer cells, like radiotherapy and chemotherapy. Virotherapy, however, has several advantages. Virotherapy is selective for malignant cells without harming healthy cells. Virotherapy has two modes of action. In addition to being an oncolytic cancer treatment it also activates the immune system. Virotherapy is very important for the treatment of tumours that are insensitive to radiotherapy and chemotherapy, such as melanoma.
Virotherapy can be combined with other treatments such as surgery and under certain conditions with radiotherapy and chemotherapy. Virotherapy may reduce the immunosuppressive effect of other treatments. The first oncolytic virus approved and registered in the world is Rigvir.
Those are excerpts from article in “Cancer Virotherapy” ISSN 2256-0920, Volume 1, by Peteris Alberts, PhD and Kaspars Losans, MD