Background:  Hepatitis C virus (HCV) kinetics parameters are slower in African Americans compared to Caucasians. However, conflicting data exist on the role of HIV infection. We hypothesized that lower sustained virologic response rates in HIV/HCV patients were due to race rather than HIV status.

Methods:  We treated 26 HCV genotype 1 patients (5 HIV/HCV-co-infected African Americans, 4 HCV-mono-infected African Americans, 10 HIV/HCV-co-infected Caucasians, and 7 HCV-mono-infected Caucasians) with 180 µg of pegylated interferon-a2a with weight-based ribavirin (1000/1200 mg) for 48 weeks. HCV viral load was measured by Versant 3.0 bDNA at baseline and at 24 hours, 28 hours, and 32 hours and then days 2, 3, 4, 7, 9, 11, 14, 21, 28, 42, and 56. Wilcoxon Rank Sum test was used to compare early viral kinetics parameters between Caucasians and African Americans and between HIV⁺ and not. A 2-way analysis of variance using rank transformed data was performed to assess whether there is an interaction between race and HIV status for the viral kinetic parameters.  

Results:  Of these patients, 19 have completed therapy. In the HIV/HCV white group, 6 relapsed or had no response and 2 achieved a sustained virologic response, and 2 are on treatment. In the HIV/HCV African American group, 2 of 5 relapsed, 2 had no response, and 1 is still on treatment. In the HCV white group, 3 relapsed or had no response, and 3 achieved sustained virologic response; 1 discontinued therapy prematurely. In the African American HCV group, 1 relapsed, and 3 are still on treatment. Overall, sustained virologic response was achieved in 3 of 7 (43%) of non-HIV and 2 of 12 (17%) of HIV group. Among Caucasians, 5 of 14 (36%) achieved sustained virologic response, but 0 of 5 in the African American group thus far. No difference in log HCV RNA at baseline was seen between African American and Caucasian groups. The Caucasian group had a faster decline in HCV RNA from baseline to day 3 (first phase), –0.77 vs. –0.27, p = 0.02. The second phase slope was faster in the whites (0.38 vs 0.23, p = 0.06). No differences were found in first or second phase decline in HIV compared to non-HIV groups. No interaction between HIV and race was found with the viral kinetic parameters.

Conclusions:  Early viral kinetics was slower in African American in both first and second phases, which may explain lower sustained virologic response rates; but first and second phase decline were similar in both HIV⁺ and HIV^– patients. Thus, response to interferon appears different in African Americans but similar between those with HIV-infection and those without. Lower sustained virologic response rates seen in the HIV population may be due to impaired late immune clearance of HCV or higher proportion of African Americans with HIV/HCV. Different treatment strategies are needed to improve responses for African Americans and HIV/HCV-co-infected patients.