Clinical

African Americans have lower response rates to HCV therapy

Last Updated: 2006-08-29 11:46:46 -0400 (Reuters Health)

NEW YORK (Reuters Health) - African American adults with chronic hepatitis C virus (HCV) infection are less likely to respond to standard combination therapy with peginterferon and ribavirin, a study in the August issue of Gastroenterology confirms.

The reduced response rate among African American patients is not caused by "the usual predictors such as patient age, gender, pretreatment serum HCV concentrations, amount of fibrosis in the liver biopsy nor amount of medication taken," Dr. Charles D. Howell of the University of Maryland School of Medicine in Baltimore notes in a statement issued by the American Gastroenterological Association.

In a multicenter treatment trial, 196 African American and 205 Caucasian American treatment-na�ve patients with HCV genotype 1 infection and similar baseline characteristics received peginterferon alfa-2a (180 micrograms/week) and ribavirin (1000 to1200 mg/day) for up to 48 weeks.

The sustained virologic response rate was 28% in African Americans compared with 52% in Caucasian Americans, a significant difference with a p value < 0.0001.

Racial differences in viral responses were evident as early as 4 weeks after the start of treatment, the team notes. Breakthrough viremia occurred more frequently in African Americans than Caucasian Americans (13% vs. 6%, p = 0.05), but relapse rates were comparable (32% vs. 25%, p = 0.30).

The proportion of the total maximum dose of peginterferon and ribavirin taken was lower among African Americans than Caucasian Americans. However, in multivariate analysis, this did not account for the racial difference in sustained virologic response rates.

According to Dr. Howell, "the basis for the racial difference in virologic response rates is being addressed by ongoing supplementary studies in genetics, immunology, interferon signaling and pharmacology, and virology."

Gastroenterology 2006;131:470-477.