Amantadine therapy for chronic hepatitis C: A randomized double-blind placebo-controlled trial

OBJECTIVE: Although treatment of hepatitis C has improved, up to 50% do not respond to standard therapy with interferon regimes or cannot tolerate the treatment due to side effects. The purpose of the present investigation was to evaluate the safety and effectiveness of the antiviral drug amantadine for the treatment of hepatitis C in those who had either previously failed interferon therapy or were not candidates for interferon. DESIGN: A prospective double-blind randomized placebo-controlled trial. SETTING: Outpatient research clinic of a teaching hospital. PATIENTS/PARTICIPANTS: One hundred fifty-two patients with confirmed hepatitis C with abnormal liver enzymes, detectable hepatitis C RNA in the blood, and abnormal liver histology by biopsy were randomized to receive treatment or placebo. MEASUREMENTS AND MAIN RESULTS: Patients received either amantadine 100 mg twice daily by mouth or placebo for 6 months. After 6 months, placebo-treated patients were crossed over and treated with amantadine for 6 months and amantadine-treated subjects received 6 additional months of therapy. Amantadine therapy resulted in a significant decline in seram alanine aminotransferase compared to placebo (P = .03). Nine percent cleared the virus at the end of therapy and 6.8% had a sustained virologie response 6 months after discontinuation of amantadine, but this was not statistically significant. Side effects were minimal, and the social quality of life survey improved with 12 months of amantadine (P = .02). CONCLUSIONS: Oral amantadine may provide a safe alternative treatment for those patients who are intolerant or unresponsive to interferon.