New Therapy Packs Powerful One-Two Punch Against HCV
A leading hepatologist refers to the recently approved combination antiviral therapy for chronic Hepatitis C (HCV) as a significant breakthrough.
Rebetron, manufactured by Schering-Plough Corp., (Kenilworth, NJ) consists of a 6-month course of interferon injections combined with ribavirin capsules. It was approved by the FDA in June for adult Hepatitis C patients who initially respond to and later relapse with standard treatment (interferon alone).
An estimated 4 million Americans are believed to be infected with HCV. The virus is responsible for about 10,000 deaths a year in this country, and is the leading indication for liver transplantation.
Interferon alone eliminates the virus in only 10%-20% of patients, but another 25%-40% respond and subsequently relapse. In patients for whom the FDA approved the therapy, nearly half experienced a sustained remission (6 months or more) when administered the interferon/ribavirin combination in trials held in both the United States and Europe, roughly 10-fold better than the patients who received interferon alone.
Although the FDA approved the therapy specifically for the subgroup of patients who relapse after responding to interferon alone, physicians will be able to prescribe the treatment for patients as a first course. While the FDA has not yet reviewed the data, Willis C. Maddrey of the University of Texas Southwestern Medical Center in Dallas notes that published results out of Europe suggest that naive patients respond better to the combination.
From 20% to 40% of HCV patients develop cirrhosis, but the clinical complications often take as many as 20 years to present. Maddrey points out that patients who are not cirrhotic have shown a substantially higher response rate to the treatment than those who are in a later stage of the disease. “I cannot see a patient right now and accurately predict that he will or won’t develop cirrhosis in 20 years,” Maddrey says. “But I can say that if you take your chances and don’t get treated, and you develop cirrhosis, you’re going to be much more resistant to treatment.”
Of course, the new treatment won’t be for everyone. The side effects of the combination therapy are potentially serious, because ribavirin causes a nonimmune hemolytic anemia, with an average drop in hemoglobin of about 2 g. “It’s important for physicians to plan for that, to test patients’ hemoglobin levels before treatment and at 2 and 4 weeks, and not to use this drug in anyone who couldn’t stand a moderate drop in hemoglobin,” says Maddrey.
The combination therapy is also expensive, estimated at $6400-$8600 for the 6-month course. But Maddrey suspects that cost-efficacy studies will ultimately support the new therapy’s use.
As for the slight majority of HCV patients who don’t respond to the Rebetron, Maddrey predicts that the next breakthrough will come with the addition, not substitution, of another antiviral drug, possibly a protease inhibitor, to the combination treatment. “It’s similar to what occurred in AIDS, where we did well with AZT for awhile, but the real breakthrough came when we added a protease inhibitor to the AZT,” he says. “We feel that multidrug therapy is the wave of the future, and that hitting this virus in two or three sites gives us a much better chance of eradication.”
© 1998 by The American Gastroenterological Association