April 28, 2011 -- A major advance for treating hepatitis C is likely headed to market after government advisors backed two new drugs this week.
Studies suggest the drugs could as much as double the effectiveness of current treatments for the potentially fatal liver disease. That could improve prospects for tens of thousands of patients and may bring thousands of more chronic sufferers into treatment, experts say.
An expert panel unanimously recommended Thursday that the FDA approve a new drug called telaprevir, saying it effectively cuts the level of hepatitis C virus (HCV) in the bloodstream of infected patients. The decision comes on the heels of another unanimous vote Wednesday backing a similar drug called boceprevir.
As many as 3.9 million Americans are infected with HCV, though up to three-quarters of them don’t know it. Millions of Americans were infected with HCV because of tainted blood products in the 1990s and earlier. Today, sharing of needles by users of illicit drugs is a major source of infection.
How Telaprevir and Boceprevir Work
Telaprevir, made by Vertex Pharmaceuticals, and boceprevir, made by Merck, are both part of a new class of anti-HCV drugs known as protease inhibitors. Like similar medications already used against HIV, the drugs suppress HCV by disrupting the reproduction of the virus.
Most HCV patients now face months of treatment with ribavirin and interferon, which are used to boost the immune system. The treatment is complicated, expensive, fraught with side effects, and requires close attention from doctors and patients.
But data from both Vertex and Merck suggest the new protease inhibitors could increase treatment effectiveness from about 40% now to nearly 80%, on average. Clinical trials submitted by the companies suggested the drugs can also shorten the length of treatment from a year to as little as 24 weeks.
Praise From the FDA Panel
The results prompted high praise rarely heard by the FDA’s scientific advisors.
“I started pinching myself, saying, ‘Is it really possible I’m looking at numbers like this?’ Because it really is unbelievable,” said Victoria Cargill, MD, director of minority research at the National Institutes of Health’s Office of AIDS Research and the panel’s chair.
”For those of us who’ve been in the field, thisis a very exciting moment,” said Lawrence S. Feldman, MD, a professor of medicine at Harvard Medical School and a member of the panel.
Several company officials and advisors referred to the drugs as the first potential cure for hepatitis C.
“I am thrilled by today’s decision,” said Camilla Graham, MD, the vice president for global medical affairs for Vertex.
Other classes of antiviral drugs for HCV are expected to come up for FDA approval in the next few years. Robert Conslavo, a spokesman for Merck, likened the new drugs to AZT, the first widely used antiviral drug that revolutionized treatment of HIV and AIDS.
The drugs could for the first time give doctors a way to treat a certain genetic subtype of HCV that until now had proven difficult to treat. About 75% of patients carry HCV genotype 1, the virus that is most likely to mount resistance to ribavirin. Both telaprevir and boceprevir appear particularly effective at targeting HCV genotype 1.
New Drug Drawbacks
Amid all the excitement, though, there were caveats. Telaprevir and boceprevir must be taken in addition to ribavirin and interferon. That would make the already complicated treatment course for hepatitis C even more complex and requiring the care of experienced specialists.
In addition, more than half of patients taking telaprevir in clinical trials developed often widespread skin rashes. In about one in 14 patients, the rash was so severe patients stopped taking their treatments.
Both drugs can also increase the risk of anemia, already a side effect of concern in patients on available medications. In most cases they must be taken every eight hours with fatty food, a potentially difficult prospect for patients already feeling sick.
“These treatments are still going to be difficult for patients,” said Martha Saly, director of the National Viral Hepatitis Roundtable, a consortium of non-profit and industry groups. Still, “it will be monumental what we can do with these new treatments."
Experts Thursday urged the FDA to label telaprevir with warnings for patients and doctors about the risk of severe rash. Patients should be warned not to stop their treatment if a rash develops, they said.
Federal rules require the FDA to make a decision on both drugs before the end of May. The agency doesn’t have to follow advisory panel decisions, though it usually does.