The present invention relates to a new cyclic peptide compound or a salt thereof, which has anti-hepatitis C virus activities based on inhibitory activity against the RNA replication of hepatitis C virus replicon, to a process for preparation thereof comprising a rearrangement reaction under a mild acidic condition and the following amino acid changing reactions etc., to a pharmaceutical composition comprising the same, and to a method for prophylactic and/or therapeutic treatment of hepatitis C in a human being or an animal.本發明有關一種新穎之環肽化合物或其鹽，其基於對抗C型肝炎病毒複製子之RNA複製的抑制活性而具有抗C型肝炎病毒活性；有關該化合物之製備方法，包含在溫和之酸性條件下之重排反應及後續之胺基酸改變反應等；有關包含該化合物之醫藥組成物；且有關用以預防及/或治療人類或動物之C型肝炎的方法。
