November 20, 2010

Vaccine testing for hepatitis C promising

Trials in England show boosted immunity

By AARON DERFEL, The Gazette November 20, 2010

Scientists are zeroing in on a promising vaccine to treat hepatitis C, an international symposium was told yesterday in Montreal.

Three preliminary clinical trials in England are showing that a so-called therapeutic vaccine can boost the immune response in those infected with the hepatitis C virus.

Still, a viable vaccine is a decade away, said Paul Klenerman, a University of Oxford physician researcher who is conducting the trials.

"Other vaccine trials have been done already, but ours is the first where we're treating people (with drugs) and giving them the vaccine at the same time."

"What's possible is that you can have a good drug that can get most of the virus, but you might still need a bit more immune response to tidy it all up, because what you don't want to do is have all these drugs suppress it and then it comes back again, which is typically what happens," Klenerman explained.

Hence the need for a therapeutic vaccine, he said. The Oxford trials of about 100 individuals have shown an increased immune response in T cells.

Hepatitis C, first identified as a virus in 1989, is estimated to affect 300,000 Canadians. The infection is at first asymptomatic, but once it takes hold, hepatitis C can progress to scarring of the liver as well as the ultimate failure of the organ. It can also cause liver cancer.

About 20 per cent of people infected are able to clear the virus, HCV, from their bodies. However, the balance must live with chronic hepatitis.

Drugs like interferon-alpha-2b and ribavirin are effective in the long run in slightly more than half of patients with chronic hepatitis.

Many Canadians contracted hepatitis C as a result of tainted blood transfusions from 1980 to 1990. Today, IV drug users are at the greatest risk of HCV infection.

Alain Lamarre, a professor in immunology at the INRS-Institut Armand-Frappier in Laval and chairman of the symposium, said he sees great potential in therapeutic HCV vaccines.

"People with chronic hepatitis C - if they are not treated -accumulate tremendous amounts of virus circulating in their bodies," Lamarre said. "The first goal is to reduce that to a minimal level, and therapeutic vaccines would help."

The symposium was organized by Immunology Montreal, a non-profit organization that promotes education and research.

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