T-VEC Vaccine Promotes Tumor Shrinkage in Advanced Melanoma

Source: Cancer Connect.com, April 2014

The experimental cancer vaccine talimogene laherparepvec (T-VEC) promoted tumor shrinkage and triggered a systemic immune response in patients with advanced melanoma, according to the results of a study presented at the 2014 Society of Surgical Oncology Annual Cancer Symposium in Phoenix, Arizona.

Of the more than one million new diagnoses of skin cancer each year, roughly 76,000 involve melanoma. More than 9,000 people die of melanoma each year in the United States. Melanoma is dangerous because it is more likely than other types of skin cancer to spread (metastasize) to other parts of the body. Important progress has been made in the treatment of this disease in recent years, but researchers continue to seek new and more effective drugs.

T-VEC is a type of immunotherapy that uses a specially designed virus to destroy cancer cells. It is injected directly into the tumor. After acting locally within the tumor, it is intended to prompt an immune response against cancer cells elsewhere in the body.

Using data from a phase III study presented at ASCO in 2013, researchers analyzed 3,219 tumor lesions (in 286 patients) to study the response to the drug in injected versus non-injected tumors. Overall, 2,043 lesions were injected with T-VEC at least once, 1,022 were un-injected non-visceral, and 154 were un-injected visceral lesions.

The results showed that 64 percent of injected tumors shrank by half, while 32 percent of un-injected non-visceral and 16 percent of un-injected visceral lesions shrank by half.

A total of 6 patients converted from inoperable to operable melanoma after receiving T-VEC. In total, 37 surgeries were performed during the course of the trial: 15 resulted in no evidence of disease and 3 showed a pathologic complete response.

The vaccine shrank tumors that were directly injected as well as those that were not injected—indicating that the vaccine was triggering the immune system to fight the distant tumors. The researchers concluded that this promising new agent warrants further study.