Doctors Use Herpes to Kill Skin Cancer

The herpes virus has found its sole positive use: to combat melanoma, the deadliest of skin cancers.

Research results published in the Journal of Clinical Oncology indicated how the treatment, called Talimogene Laherparepvec (T-Vec), worked to halt the disease progression in melanoma patients.

The research team, led by Kevin Harrington, professor of biological cancer therapies, Institute of Cancer Research (ICR) and the Royal Marsden NHS Foundation Trust, United Kingdom, conducted a study representing the first phase 3 trial to “demonstrate the benefits of viral immunotherapy for cancer patients”.

Harrington and his colleagues randomized a cohort of 436 patients already afflicted with advanced, inoperable malignant melanoma to either receive a T-VEC injection or control immunotherapy.

T-VEC was modified to produce the GM-CSF molecule, which signals the human immune system to demolish cancer cells. Furthermore, the virus was genetically engineered to eliminate two genes, ICP345 and ICP47, largely to prevent them from multiplying.

The team found that 16.3% of patients who received the T-VEC treatment experienced a stronger response lasting more than six months, compared with only 2.1% of the patients who simply were administered the control immunotherapy.

The researchers found patients with less advanced forms of the cancer had manifested the strongest responses to T-VEC along with those who had not undergone any other treatment for the disease, which shows T-VEC could potentially be used as the primary treatment for inoperable metastatic melanoma.

Researchers also noted that while patients with stage III and early stage IV melanoma, who were given the control immunotherapy, survived for an average of 21.5 months, those who received T-VEC lived for a mean of 41 months.

"It is encouraging that the treatment had such a clear benefit for patients with less advanced cancers," said Harrington. "Ongoing studies are evaluating if it can become a first-line treatment for more aggressive melanomas and advanced disease.”

Harrington commented, “There is an increasing excitement over the use of viral treatments like T-VEC for cancer, because they can launch a two-pronged attack on tumors — both killing cancer cells directly and marshalling the immune system against them.”

Most importantly, viral treatments can specifically target cancer cells, so “it tends to have fewer side effects than traditional chemotherapy or some of the other new immunotherapies.”

Developed by the pharmaceutical company Amgen, the drug was submitted to both the FDA and the European Medicines Agency, potentially available to US patients by next year if approved, and in Europe soon after.