FOR IMMEDIATE RELEASE: April 8, 2003
Contact: Bill Seiler bseiler@umm.edu 410-328-8919
Ellen Beth Levitt eblevitt@umm.edu 410-328-8919

UNIVERSITY OF MARYLAND RESEARCHERS STUDY DIFFERENCES IN RACIAL RESPONSE TO ANTIVIRAL THERAPY FOR CHRONIC HEPATITIS C

Researchers at the University of Maryland School of Medicine in Baltimore are trying to find out why African Americans who have the hepatitis C virus do not respond as well as whites to hepatitis C treatments. The researchers are taking part in an NIH-sponsored, multi-center study to compare the effectiveness of a common drug regimen in 400 people diagnosed with the most resistant form of the hepatitis C virus, genotype 1. Half of the participants are African American, the rest are Caucasian.

Hepatitis C, a blood-borne viral disease, attacks the liver and kills 8,000 to 10,000 people a year. While there are preventive vaccines for hepatitis A and B, no vaccine exists for hepatitis C.

African Americans are twice as likely as whites to have hepatitis C, but current treatments do not seem to work as well for them. Recent studies suggest there may be major racial differences in treatment response, especially among individuals infected with genotype 1 of the hepatitis C virus. For example, in one study, combination therapy using the antiviral protein interferon and ribavirin, which stimulates virus-fighting T cells in the body, was able to get rid of the hepatitis C virus in 37 percent of Caucasian patients, but was effective in only 21 percent of the African American patients.

A more recent small study of combination therapy in patients with hepatitis C virus genotype 1 resulted in a 52 percent response rate in Caucasians and a 32 percent response rate in African Americans.

"We don't know why the responses are different, but we're exploring a number of possibilities," says Charles D. Howell, M.D., associate professor of medicine at the University of Maryland School of Medicine and principal investigator of the project at the University of Maryland Medical Center. "In some studies, the lower response rate in African Americans may simply be a byproduct of their under-representation in hepatitis C research."

"But there may be more complex issues at play," says Dr. Howell. "Initially, it was thought that the low response was due to a greater prevalence of genotype 1 hepatitis C virus in African Americans. More recent research suggests that it is not the viral genotype, but factors in the infected individuals that vary by race." Those factors may include "differences in how the medications are absorbed and metabolized, the immune response to the hepatitis C virus, and how the virus interacts with the infected persons," according to Dr. Howell.

The study, called VIRAHEP-C, is also designed to help investigators understand the workings of a virus that accounts for about half of the nearly 4,000 liver transplants in the U.S. each year. Without treatment, hepatitis C causes cirrhosis of the liver in an estimated 20 percent of patients within 20 years after becoming infected. Liver failure occurs in 25 percent of those with cirrhosis. Up to five percent of hepatitis C patients develop liver cancer.

VIRAHEP-C researchers are recruiting 50 patients at each of eight clinical centers over a one-year period. The volunteers will be given a 48-week course of injections of a form of interferon, called peginterferon alfa, and ribavirin. Volunteers will remain in the study for two additional years of treatment and follow-up. Blood studies will also be performed throughout the trial to investigate potential mechanisms of antiviral resistance and to determine whether the therapy itself prompts the virus to respond in a variety of unpredictable ways.

Hepatitis C treatment presents a challenge because the medications often cause side effects that may be worse than the initial symptoms of infection. "The combination drug regimen, which clears the virus in up to 40 percent of genotype 1 patients, frequently makes them feel ill, prompting them to halt treatment early, before the virus has cleared," says Dr. Howell. Side effects may include flu-like symptoms, depression, rashes and abnormal blood counts.

Despite the side effects, the sooner treatment can begin, the better the chances of preventing complications such as liver failure and liver cancer. But there is an additional treatment challenge. It may take up to 20 years for serious, recognizable physical symptoms to appear. If early symptoms do occur, they may resemble mild flu. Prior to treatment, infected people can spread the virus to others through exposure to their blood. The subtlety of symptoms, coupled with the fact that the hepatitis C virus is detected by a blood test that is not usually part of a routine physical examination, can contribute to a delay in diagnosis.

According to the Centers for Disease Control and Prevention (CDC), an estimated 3.9 million Americans have been infected with the hepatitis C virus. Of these, 2.7 million people have chronic infection with the virus. The CDC says the number of new hepatitis C infections has declined from an average of 240,000 per year in the 1980s to about 25,000 in 2001. But among African Americans, there has been a rise in chronic hepatitis C. In fact, about nine percent of African American men in their 40's are estimated to have the virus.

###

For patient inquiries, call 1-800-492-5538 or click here to make an appointment.


This page was last updated on: February 25, 2008.