Combination therapy with amantadine and interferon in naive patients with chronic hepatitis C: meta-analysis of individual patient data from six clinical trials

Background/Aims: In chronic hepatitis C, clinical trials evaluating the efficacy of amantadine (AMA) and interferon (INF) compared to INF monotherapy, have produced conflicting results. We performed a meta-analysis of the individual patient's data from previous studies. Methods: Nine hundred and seventy-two patients from six European centres were evaluated by means of individual patient meta-analysis, using mixed models with centres and the centre-treatment interaction fitted as random variables. Results: At the end of therapy, virological responses were 38.5% (95% CI 34.1-42.8) after INF and AMA, and 29.5% (95% CI 25.5-33.6) after INF alone (P = 0.003). Sustained response occurred in 111 (23.1%; 95% CI 19.3-20.2) and 85 patients (17.3%; 95% CI 14.0-20.7), respectively (P = 0.03). Even accounting for the centre effect, therapy with AMA and INF was more effective than IFN alone (P = 0.029). When genotypes and viraemia levels were combined, the response rate after combination therapy doubled that observed with IFN alone in all subgroups, except those with low viraemia and genotypes 2 or 3. Conclusions: In chronic hepatitis C, therapy with AMA and INF is effective and may be an alternative to INF and ribavirin in patients who cannot tolerate ribavirin.