In what’s being called a major advance toward “a complete change in the game,” the FDA has for the first time given the green light to a new form of cancer treatment—one that researchers hope might someday make chemotherapy, and its adverse side effects, a thing of the past.
The key, as it turns out, is viruses—more specifically, herpes.
Last week the FDA announced its approval of a “genetically modified live oncolytic herpes virus therapy” in which viruses are engineered specifically to hunt and kill the malignant cells associated with the skin cancer melanoma. Imlygic is injected directly into the melanoma lesions, where it replicates inside cancer cells and causes the cells to rupture and die. After the initial injection, a second dose is administered three weeks later, followed by additional doses every two weeks for at least six months, unless other treatment is required or until there are no remaining injectable lesions to treat.
What makes this particular herpes virus special is its unique genetic engineering, which causes it to infect malignant cells while ostensibly avoiding healthy ones. In other words, it targets cancer, with minimal risk of giving a patient herpes, as we commonly know it (although, the FDA warns, some risk still remains for those with suppressed immune systems, or women who are pregnant). And while the agency does list several other potential side effects, such as fever, chills, and “flu-like symptoms,” these seem mild compared to the draining effect of current cancer treatments.
An article published this past May in the Journal of Clinical Oncology describes the results of a large round of clinical testing of the procedure. The results weren’t groundbreaking—this is a treatment, and not a cure—but as the study’s authors write, “T-VEC represents a novel potential therapy for patients with metastatic melanoma.”
Beyond melanoma, however, researchers see the FDA’s approval of Imlygic as an important milestone when it comes to using smart viruses to treat other forms of cancer. As Mayo Clinic oncolytic virotherapy researcher Dr. Stephen Russell explained to The Guardian, the FDA’s approval of Imlygic opens the door to further research into the use of viruses to target diseased cells.