Foe turned Friend: Herpes virus tricked into helping fight cancer

We are really starchemotherapyting to get creative in the way we treat cancer. In April we brought you the story of researchers who used the polio virus to treat brain cancer. Earlier this month we discussed some big advances in personalized medicine drugs and last week we discussed the success physicians are having using melanoma drugs to treat leukemia. Now there s another revolutionary treatment for cancer, but it s not a drug, it s the herpes virus.

Herpes is a common infection that is caused by the herpes simplex virus (HSV) and usually manifests as a small blister, or cold sore, in a variety of places such as the genitals, throat or lips. At the cellular level, HSV, like all viruses, becomes intracellular and takes over the host cell s machinery in order to produce viral proteins. Eventually, the takeover leads to the human cell bursting open.

When you really think about the viral life cycle, it s fairly obvious how it can be exploited to treat cancer and in a study out in this month s Journal of Clinical Oncology, researchers announced they are pretty close to doing this successfully. The researchers, working in healthcare settings around the world, administered a modified HSV to about 300 patients with inoperable advanced melanoma.

The modified virus (named T-vec) is limited to entry and replication in tumor cells only and induces the cancer cells to produce an immune protein which stimulates the local immune system. In essence it s a two pronged attack, the virus enters the cells and sends a big signal out to the immune system to attack the tumor cells and then the virus goes to work on killing the tumor cells. Furthermore, the modifications to the virus make sure that healthy cells are left alone.

In the study, 26 percent of patients responded to the T-vec treatment, which may sound modest; however, this contrasts with the 6 percent of patients in the trial who responded to the standard treatment. Of the 26 percent, ten percent exhibited total remission. Another 16 percent saw their tumors reduced by more than 50 percent. Furthermore, the patients reportedly exhibited few or no side effects and no reported fatalities from the treatment.

For those who have a lot of hope for viral treatment of cancers this trial, which was a phase III clinical trial, is a major accomplishment. The trial s leader Professor Kevin Harrington, from the Institute of Cancer Research in London, said It's not an exaggeration to say this is a first-in-class agent, an entirely new type of anti-cancer treatment. There will have to be discussions about cost effectiveness but we hope to see this agent receive approval in about the next 12 months, making it possible to prescribe it for cancer."