The pharmacokinetics of peginterferon alfa-2a and ribavirin in African American, Hispanic and Caucasian patients with chronic hepatitis C


Correspondence to:

Dr B. J. Brennan, 340 Kingsland St, Building 721, Nutley, NJ 07110, USA.




Amongst Caucasian, Hispanic and African Americans with genotype 1 hepatitis C virus (HCV), there is a wide variation in response to treatment with peginterferon alfa-2a (PEG-IFN alfa-2a) and ribavirin.


To evaluate the pharmacokinetics (PK) of PEG-IFN alfa-2a and ribavirin among these three groups.


Forty-seven patients with genotype 1 CHC (17 African Americans, 14 Hispanics and 16 Caucasians) received 8 weeks of PEG-IFN alfa-2a (180 &g/week) and ribavirin (1000 or 1200 mg/day). PEG-IFN alfa-2a serum concentrations and ribavirin plasma concentrations were measured following the first dose and at week 8. Pharmacokinetic parameters (Cmax, Tmax, AUC, CL/F) were estimated using noncompartmental methods.


There was no difference in the pharmacokinetic parameters for PEG-IFN alfa-2a following single-dose or steady-state administration between African American or Hispanic patients compared with Caucasian patients. Ribavirin pharmacokinetic parameters were similar between Hispanic and Caucasian patients for single-dose and steady-state administration. The single-dose Cmax was 33% lower (< 0.05) in African American compared with Caucasian patients. Other ribavirin single-dose and steady-state pharmacokinetic parameters were slightly decreased (approximately 20% lower) in African American patients, but were not considered clinically meaningful.


No differences were observed in PEG-IFN alfa-2a pharmacokinetic parameters between African American or Hispanic patients compared with Caucasian patients. For ribavirin, no differences were observed in pharmacokinetic parameters between Hispanic and Caucasian patients. While a trend towards increased ribavirin clearance and decreased exposure was observed in African American patients vs. Caucasian patients, the differences were small and not considered clinically meaningful (Clinical Trial Number: NP17354).