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What Explains Low Response Rates to INF in Blacks with HCV Infection?

Lack of an early virologic response was associated with lower rates of sustained response to INF therapy for HCV infection in blacks compared with non-Hispanic whites.

Blacks infected with hepatitis C virus (HCV) have been shown to have lower response rates to interferon (INF) therapy than do other ethnic groups, but the underlying reasons are unclear. Previous studies have been limited by small size and retrospective design. In this prospective study, researchers compared the response to 48 weeks of pegylated INF alfa-2b (1.5 µg/kg) in 100 blacks and 100 non-Hispanic whites. All patients also received twice-daily ribavirin (1000 mg for the first 12 weeks, then 800 mg for weeks 13 through 48). In both groups, 98% of patients had genotype 1 infection

About 80% of patients in both groups completed treatment. Depression was the most common reason for discontinuation. The rate of sustained virologic response was significantly lower in blacks than in whites (19% vs. 52% among all patients and 23% vs. 66% among patients who completed 48 weeks of therapy). Blacks were less likely to experience an early virologic response (a reduction in HCV RNA level by at least 2 log IU at 12 weeks; 40% vs. 69%, P<0.001). Blacks who did have an early virologic response were less likely to have sustained responses than whites (48% vs. 75%, P<0.001). Results of univariate and multivariate logistic analysis revealed that race and age were significantly associated with response: Blacks and patients aged 40 or older were less likely to respond than whites and younger patients. Response rates did not differ among patients treated in university versus community settings. Adverse-event rates were similar in blacks and whites (about 23%).

Comment: In this prospective study, blacks had significantly lower rates of sustained response to INF therapy for HCV infection than non-Hispanic whites did. This difference was not related to adherence, socioeconomic status, duration of therapy, or genotype; rather, it appeared to be related to the lack of an early virologic response. We don't know why blacks with HCV infection have significantly reduced response rates to INF, but these patients should receive additional counseling.

— Kenneth D. Flora, MD

Published in Journal Watch Gastroenterology August 11, 2004

Citation(s):

Muir AJ et al. Peginterferon alfa-2b and ribavirin for the treatment of chronic hepatitis C in blacks and non-Hispanic whites. N Engl J Med 2004 May 27; 350:2265-71.

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