A cancer drug based on a tumor-killing virus has given a lift to a technology that has long tantalized doctors and researchers. Amgen, which is developing the drug, said late Tuesday that it had met the primary goal of a Phase 3 clinical trial in patients with advanced melanoma, the deadliest type of skin cancer.
In the trial, 16 percent of the patients who had the treatment, called talimogene laherparepvec, or TVEC, experienced a significant shrinkage of their tumors that lasted at least six months. That compared with only 2 percent of the patients in a control group.
Amgen said that while people getting TVEC were living longer, it was too early to say definitively whether the drug had improved survival, something that might be known late this year. A company spokeswoman said it was also too early to say whether Amgen would file for regulatory approval based on the trial results.
TVEC is a herpes simplex virus, the type that causes cold sores, that is modified in such a way that it replicates in fast-growing cancer cells but not healthy ones. It also contains an implanted gene for GM-CSF, a protein that stimulates the immune system.
The drug is injected directly into skin tumors. As the virus replicates inside the cells, those cells produce GM-CSF.
Eventually the replicating viruses cause the cell to burst, freeing the virus and the GM-CSF in the presence of tumor components. That is supposed to stimulate a systemic immune response that can kill cancer cells throughout the body.