ONCOLYTIC THERAPY MAY BE EFFECTIVE FOR HCC

NEW YORK (Reuters Health) - A novel recombinant vaccinia virus kills hepatocellular carcinoma (HCC) in human cells in vitro and in mice, according to a report from U.S. and German researchers.

"HCC is a tumor type very resistant to chemotherapy and radiation," senior author Dr. Yuman Fong told Reuters Health by email. "It is hoped that this new strain of virus will be able to be brought to clinical trial in a disease that affects over a million people worldwide yearly."

In a paper online June 3 in Surgery, Dr. Fong of City of Hope Medical Center in Duarte, California, and colleagues note that 70% to 85% of patients with HCC are diagnosed at an advanced stage and most will die within six months.

Oncolytic viruses, which can selectively infect, replicate within and kill cancer cells, are a promising therapeutic option. They can also deliver targeted gene therapies and provide disease-progression tracking as well as accurate visualization of tumor burden.

In particular, the researchers investigated the ability of GLV-2b372, a novel light-emitting recombinant vaccinia virus derived from a wild-type Lister strain, to kill HCC. It produces fluorescing protein in infected cells for real-time monitoring of viral infection.

The team introduced the virus into four human HCC cell lines. It acted in a time- and concentration-dependent manner with 70% cell death in all cell lines by day 5. All cell lines supported efficient viral replication.

They then went on to test intratumoral injection in flank HCC xenografts generated in athymic nude mice. At 25 days, tumor volumes decreased by 50%. In controls they increased by 400%.

Moreover, three out of four animals treated with GLV-2b372 had complete resolution of tumor.

The researchers conclude that in contrast to other viral vectors, GLV-2b372 "not only significantly reduces tumor burden, but can completely eradicate tumor."

Further modification, they conclude, "could result in a superior oncolytic viral platform for the treatment of HCC."

Dr. Fong added that last month, members of the FDA's Oncologic Drugs Advisory Committee and Cellular, Tissue and Gene Therapies Advisory Committee voted 22 to 1 to recommend to the FDA approval of the oncolytic virus talimogene laherparepvec (T-Vec, Amgen) for treatment of melanoma.

This, he said, "will be the first gene therapy approved in America."

SOURCE: http://bit.ly/1N2b5YE