Oncolytic medicines, also known as oncolytic virotherapy, are a class of therapeutic agents that use viruses to selectively infect and kill cancer cells. These viruses are designed to exploit the unique characteristics of cancer cells while sparing normal, healthy cells. Oncolytic medicines are typically genetically engineered or modified viruses that have been specifically designed to target and replicate within cancer cells. Once inside the cancer cells, the viruses replicate and spread, eventually leading to the destruction of the tumor cells. This can occur through direct lysis (cellular breakdown) of the cancer cells, induction of an immune response against the tumor, or disruption of the tumor’s blood supply.