Chemo Drug Helps Cancer-Killing Virus

U.S. scientists say they’ve discovered a specific chemotherapy drug helps a cancer-killing virus being tested for the treatment of incurable brain tumors.

The Ohio State University researchers say the virus, a modified herpes simplex virus, is injected directly into the tumor, where it enters only the cancer cells and kills them.

However, the study found that within hours of the injection, infection-fighting immune cells are drawn into the tumor to attack the virus, reducing the treatment’s effectiveness.

But the scientists also report finding a chemotherapeutic drug called cyclophosphamide briefly weakens those immune cells, giving the anti-cancer virus an opportunity to spread more completely through the tumor and kill more cancer cells. Specifically, the drug slows the activity of immune cells called natural killer cells and macrophages, which are the body’s first line of defense against infections.

The virus and drug cannot be used yet in humans because they require further study, as well as testing for safety and effectiveness.

The research appears in the Aug. 22 issue of the Proceedings of the National Academy of Sciences.