An oncolytic virus is a naturally occurring or genetically engineered virus designed to selectively infect, replicate within, and destroy cancer cells while leaving healthy tissue unharmed, simultaneously stimulating an anti-tumor immune response. Oncolytic viruses exploit tumor-specific defects in antiviral signaling pathways — such as impaired interferon response — to achieve selective cancer cell lysis and immunogenic cell death. They represent an emerging class of cancer immunotherapy and are classified as ATMPs in the European Union, requiring GMP manufacturing, viral vector production expertise, and specialized analytical characterization capabilities from CDMOs.
