Study of the Pharmacokinetic Action of Amantadine and Ribavirin in Chronic Hepatitis C. CINAM

Peg interferon and ribavirin currently represent the standard approved association for treating patients infected with hepatitis C virus (HCV) . The adjunction of amantadine is expected to gain about 10 % of sustained virological response (SVR) . Unfortunately, about 50 % of the patients remain relapsers or virological non responders. The main predictive factors of SVR are HCV genotype and body weight (BW). The impact of the drug pharmacological properties, particularly those of ribavirin requires complementary studies. This drug has a large distribution volume and its concentrations display large inter-individual variability. Two studies performed in HCV patients found no correlation between ribavirin dose adjusted on BW and a single ribavirin time point serum concentration at steady state. The aim of this study is to investigate the pharmacokinetic-pharmacodynamic relationships of ribavirin in hepatitis C patient

The study is conducted in naive patients infected with genotype non 2 non 3 administered peginterferon alpha 2-a (40KD) weekly, and ribavirin with dose adjusted on BW (\< 75 kg 1000 mg/day, \>75 kg 1200 mg/day) for the first three months with adjunction of amantadine 200 mg daily for the following 9 months. Plasma concentration profiles of ribavirin were studied after the first dose (D0) and at W12. At each period, blood samples were collected pre-dose and 30 minutes, 1, 1.5, 2, 3, 4, 6, 8, and 10 hours post-dosing. Ribavirin concentrations were measured using liquid chromatography-tandem mass spectrometry and ribavirin area under the concentration-timcurves (AUC0-10h) were derived from plasma concentrations profiles using the linear trapezoidal rule. Virological follow-up was performed at W2, W4, W6, W8, W12, W24 and W72. Early virological response was defined by undetectable viral load at W12.