NIH consensus conference addresses hepatitis C
Combination therapy of the synthetic nucleoside, ribavirin, and pegylated interferon is the standard of care for chronic hepatitis C virus (HCV) infection, according to a panel of physicians convened by the National Institutes of Health. Combination therapy reduces HCV to undetectable levels in at least half of patients, a significant improvement over monotherapy or standard interferon-ribavirin therapy.
The endorsement of combination therapy at the NIH campus in Bethesda, Md., last month concluded three days of review of advances in treating HCV by the 12-member independent panel. The meeting was one of NIH's occasional Consensus Development Conferences, which assess the latest clinical data and recommend therapies for numerous conditions. Healthcare payers often base payment decisions on NIH consensus statements issued at the conferences.
HCV, which infects an estimated four million Americans, is a growing problem. About 2.9 million infections are chronic, a number predicted to increase fourfold over the next decade. Chronic infection causes liver fibrosis, frequently progressing after 20 years or longer to terminal illness. HCV is the most common cause of cirrhosis and hepatocellular carcinoma in the United States, and end stage liver disease caused by HCV is the major reason for liver transplants.
The most recent advance is pegylated interferon. Pegylation bonds the polymer polyethylene glycol (PEG) to proteins in order to extend protein half-life in the bloodstream. Pegylation makes therapeutic effects last longer and dosing less frequent. Last year, the Food & Drug Administration approved Schering-Plough's pegylated interferon, PEG-INTRON, and the agency is now considering approval of a competitor from Roche, PEGASYS. Both are administered once a week. Endorsement of combination therapy was based on published clinical trial data on both drugs.
The physicians at the conference declared that antiviral therapy should now be considered for all HCV patients. Their statement expands the population of eligible patients to include the elderly, psychiatric patients, drug abusers, and former abusers of alcohol. Further adding HIV patients and patients with advanced cirrhosis to the list, James L. Boyer of Yale Medical School, who chaired the conference, said, "We now know these patients respond to treatment, often as well as healthy patients."
Clinical trials have not established the optimal dose of PEG-interferon, according to the NIH consensus statement, and it's too early to know whether combo therapy improves survival. Clinical data do indicate that decreasing HCV to undetectable levels reduces liver fibrosis, lowers the chance of recurring infection, and reduces the occurrence of liver cancer.
The panel also noted that combination therapy was not equally effective for everyone. For nearly 80% of patients infected with HCV variants known as genotypes 2 and 3, combination therapy lowered HCV to undetectable levels within 24 weeks of treatment. In contrast, 46% of patients with genotype 1 (which infects 70% of patients) had undetectable HCV after 48 weeks of treatment.
Tom Hollon. NIH panel endorses combo therapy for hepatitis C. Drug Topics 2002;13:14.