FDA approves cancer-killing cold sore virus as therapy for late-stage melanoma.
The FDA announced on Oct. 27 that it has approved, for the first time, an oncolytic (cancer-killing) viral therapy in the United States. The drug was approved for use against late-stage melanoma, a deadly skin cancer that can be difficult to treat.
The approval came as the result of a recent Phase III study, which showed that more patients with late-stage melanoma, treated with a herpes cold sore virus designed to kill tumor cells, had a better response when compared to a different treatment. Robert Andtbacka, M.D., from Huntsman Cancer Institute at the University of Utah and Howard L. Kaufman, M.D., from Rutgers Cancer Institute of New Jersey, led the multisite study, published May 26 online in the Journal of Clinical Oncology.
The researchers employed a genetically modified herpes virus, made by the pharmaceutical company Amgen, which was designed to replicate inside tumors and kill them. In addition, the virus contains a human gene to make granulocyte macrophage colony-stimulating factor (GM-CSF) with the goal of causing an anti-tumor immune response in the patient.
In the clinical trial, patients with Stage IIIB, IIIC, or IV melanoma were randomized to receive either the virus therapy talimogene laherparepvec (T-VEC) injected directly into their tumors or to receive an injection of GM-CSF under the skin.
The researchers observed that T-VEC virus immunotherapy caused tumors to shrink compared to treatment with GM-CSF alone: 16 percent of T-VEC treated participants (n = 295) experienced a durable response, meaning that their tumors shrank for >6 months, relative to 2 percent of the GM-CSF alone group (n = 141). While patients’ lifespans, on average, were only extended by a small amount (4.4 months), 32 (11 percent) of the T-VEC recipients and one GM-CSF recipient (<1 percent), showed no signs of cancer after treatment.
Both local and systemic immune responses after treatment with T-VEC were also observed by the researchers, supporting the idea that combining T-VEC with other immunotherapies might further increase effectiveness. Studies testing such combination therapies are currently underway.
According to researchers, the most common adverse effects of the T-VEC treatment were modest, consisting of flu-like symptoms, such as fatigue, chills, nausea, and injection-site reactions. Although more severe adverse effects did occur in some patients, the only one occurring in > 2 percent of T-VEC treated patients was cellulitis, a potentially dangerous skin infection (2.1 percent).
T-VEC represents a novel treatment option for patients with injectable metastatic melanoma. This collaborative work was enabled by Amgen, manufacturer of the T-VEC virus and will be marketed under the name IMLYGICTM.
Click here to read the FDA’s press release.