A pilot study of combination therapy with initial high-dose interferon and amantadine hydrochloride for patients with chronic hepatitis C with the genotype 1b virus.

Background/Aims: Interferon monotherapy for patients with chronic hepatitis C has been suboptimal. We studied the effect of the combination therapy of an initial high-dose of interferon and amantadine. Methodology: We investigated the virological response of 20 patients with naive chronic hepatitis C with a high viral load of the genotype 1b virus. Seven patients were administered 6MU of interferon-β once daily for 6 weeks and then thrice weekly for 20 weeks, and 13 were administered 6 MU of interferon-β daily for 4 or 6 weeks and then 10 MU of natural interferon-a thrice weekly for 22 or 20 weeks. All patients were treated with amantadine hydrochloride (100mgiday) for 26 weeks during interferon administration. Results: The complete response, transient response and no response rate were 15.0%, 60.0%, and 25%, respectively. After daily administration of interferonβ intravenously, 19 patients (95.0%) showed negative tests for serum HCV-RNA by -the polymerase chain reaction method. At the end of treatment, the serum HCV-RNA was not detected in any patients treated with daily interferon-β and intermittent interferon-α with amantadine. At 6-month follow-up, three patients had eradicated HCV-RNA, who were in the group of daily interferon-β and intermittent interferon-a with amantadine. In the patients treated with daily interferon-β and intermittent interferon-a with amantadine, the complete response, transient response and no response rates were 23.1%, 76.9% and 0%, respectively. Conclusions: These findings suggest that the combination of an initial high-dose interferon and amantadine shows promising effects on the eradication of HCV-RNA in the chronic hepatitis C patients with a high viral load of the genotype 1b virus.