Clinical

Racial difference in HCV interferon response emerges early

Last Updated: 2009-04-10 8:00:59 -0400 (Reuters Health)

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - The results of a new study suggest that early differences in interferon-induced antiviral activity may explain why hepatitis C virus (HCV) therapy is usually less successful in blacks than in whites. This difference may be apparent within just one day of treatment initiation.

Findings from a number of studies have consistently shown that African Americans with chronic HCV infection have lower sustained virologic response rates than do Caucasian Americans, lead author Dr. Jay Hoofnagle, from the National Institutes of Health, Bethesda, Maryland, and colleagues state.

To better understand this finding, the researchers analyzed data from 341 patients with chronic HCV, genotype 1 infection who were treated with peginterferon and ribavirin for at least 24 weeks. The main outcome measure was the treatment response rate within the first 28 days with a focus on the factors that influenced the response, such as HCV RNA levels and patient race, gender, and weight.

The results are reported in The Journal of Infectious Diseases for April 15.

The authors found that while HCV RNA levels dropped in almost all patients, the pattern and degree of decrease was different between African and Caucasian Americans. Although the researchers had expected a difference, the fact that it was apparent within just a day or two of therapy was a novel finding. The team also found that the early HCV RNA response was a reliable predictor of the sustained virologic response rate.

At 28 days, just 12% of African Americans were HCV RNA negative compared with 22% of Caucasian Americans, the report indicates.

In addition to African American race, a higher initial HCV RNA level, more severe hepatic fibrosis, and higher body weight were predictive of a smaller reduction in HCV RNA level through day 28.

The new findings demonstrate "that the low rates of sustained virologic response among African American patients in response to interferon-based therapy appear to result, in large part, from impaired early viral kinetics," Drs. Andrew M. Tai and Raymond T. Chung, from Massachusetts General Hospital, Boston, write in a related editorial.

"Further studies are necessary to uncover the relevant mechanisms that underlie this defect in interferon signaling or interferon-stimulated gene function, with the hope that such mechanisms can be manipulated to restore interferon responsiveness in the otherwise nonresponsive host," they add.

J Infect Dis 2009;199:1101-1103,1112-1120.