cancer cells while leaving surrounding healthy cells unharmed. The attenuated virus has also been constructed to induce a powerful systemic anti tumor immune response. OncoVEXGM-CSF has now been tested in >110 patients in a broad range of solid tumors including melanoma, head & neck cancer, breast cancer and pancreatic cancer. Both the direct cell killing and systemic immune mediated mechanisms of action of OncoVEX have been clearly validated in the clinic; OncoVEX routinely destroys tumors it is directly injected into and has led to overall disease responses in multiple patients in Phase II testing. Tumors resolved through OncoVEX treatment have not been known to recur.