Genetically engineered smallpox virus may slow liver cancer

Researchers at University of California, San Diego School of Medicine recently started enrolling a clinical trial to test a genetically altered vaccinia virus to slow the progression of liver cancer.

Pexa-Vec, also known as JX-594, is a genetically engineered version of the vaccinia virus, a virus used in the smallpox vaccine. Vaccinia virus does not contain smallpox and cannot cause the disease, but the virus may be able to target cancerous tissues over normal tissues.

"This clinical trial is evaluating a drug already known to be safe as a vaccine," Tony Reid, a medical oncologist at UC San Diego Moores Cancer Center, said. "We are applying it as a potential destructive agent for liver cancer. The goal of the trial is to evaluate if Pexa-Vec can extend patients' survival through its ability to selectively target and kill cancer cells, cut off the tumor's blood supply, and activate the body's own immune system to fight the cancer."

The Phase IIb randomized clinical trial will test Pexa-Vec on patients with hepatocellular carcinoma that was unresponsive to sorafenib, the only systemic therapy currently approved by the U.S. Food and Drug Administration. The 18-week trial will compare overall survival for patients receiving the drug combined with palliative care such as pain management, nutrition and hydration to patients receiving palliation alone.

Patients receiving Pexa-Vec will have the genetically altered virus injected directly into the tumor.

Hepatocellular carcinoma is estimated to be the third most common cause of cancer-related deaths worldwide. It is estimated 22,000 people were diagnosed with hepatocellular carcinoma in 2012 and 16,000 people died from the illness.