How the Herpes Virus Is Being Used to Treat Cancer

Scientists have discovered a new ally in the fight against skin cancer: herpes. No, seriously.
The Food and Drug Administration announced Tuesday that it has approved Imlygic for the treatment of melanoma lesions on the skin and lymph nodes.

The drug is a “genetically modified live oncolytic herpes virus therapy,” says the FDA, and it’s used to treat melanoma lesions that can’t be removed completely by surgery.
Here’s how it works: Imlygic is injected into the lesions several times over a series of weeks, where it causes the cancer cells to rupture and die.
But…herpes?! It’s not as crazy as it sounds.
A modified form of herpes can kill cancer cells and stop tumors from growing, according to research published earlier this year in the Journal of Clinical Oncology. (Scientists say viruses like herpes can be preferable to chemotherapy because they can specifically target cancer cells, while chemo kills any cells that are reproducing.)
Jen Hayes, M.D., a board-certified dermatologist at Advanced Skincare & Dermatology Physicians, says this particular strain of the virus is a weak version of herpes simplex type 1, which causes cold sores. The virus helps “wake up” your immune system so that the tumor cells are recognized as something that shouldn’t be there, she says.
There is one caveat, though: The FDA warns that the injection can give people herpes.
Clearly, that’s a small price to pay compared to life-threatening skin cancer, but what happens if you already have herpes? Will the drug still work? Board-certified dermatologist Barry I. Resnik, M.D., medical director of Florida’s Resnik Skin Institute, says yes: “There should be no expectation of a less effective response when used in patients who already have the viral infection.”
However, he says, people should avoid oral anti-viral medicines when using Imlygic because the medicine will attack the virus and weaken or destroy it.
Melanoma is the most dangerous form of skin cancer, which is the most common form of cancer in the U.S. According to the National Cancer Institute, about 74,000 Americans will be diagnosed with melanoma this year, and nearly 10,000 will die from it.