On Oct. 27, 2015, the U.S. FDA approved a virus-based treatment for melanoma, according to a press release from the University of Utah.
The new treatment is a modified version of the herpes virus which causes tumor cells to rupture, according to the release. As well, the altered virus contains a human gene which signals for the production of granulocyte macrophage colony-stimulating factor (GM-CSF), in the hopes of instigating an anti-tumor immune response.
“The goal of this targeted therapy is to treat late stage patients more effectively and with fewer side effects,” says Dr. Robert Andtbacka, associate professor of general surgery at the University’s School of Medicine and one of the leaders of the multi-site Phase III study which guided the FDA’s decision, in the release.
According to a release from the FDA, the treatment is an intralesional injection into tumours which cannot be resected, followed by a second injection three weeks later, and then doses every two weeks for at least six months, unless other treatment is required or until there are no remaining injectable lesions.
In the trial (Journal of Clinical Oncology, May 26, 2015, e-published ahead of print), patients with stage IIIB, IIIC, or IV received injections of either the virus therapy—called talimogene laherparepvec or T-VEC—or GM-CSF. The research team found that 16% of the virally-treated patients experienced shrinkage of their tumours for six or more months, while only 2% of the CM-CSF patients had shrinkage for that duration. Overall, patients lived an average of 4.4 months longer, but 11% of the T-VEC treated group had no signs of cancer post-treatment.
In the University of Utah release Dr. Andtbacka says the most common adverse effects of the T-VEC treatment were modest, flu-like symptoms—fatigue, chills, nausea, and injection-site reactions. The only severe adverse event seen in more than 2% of patients was cellulitis, though the FDA release also notes that herpes virus infection is a possible adverse event.
“This safety profile is encouraging, since this is the first randomized trial of an oncolytic virus in patients with cancer,” says Dr. Andtbacka.