The invention relates to the use of cyclic compounds of general formula (I): wherein A, B, Rand R are as defined in the specification, and their use as pharmaceuticals, e.g. in the treatment of HCV infections. In particular, • Ris selected from hydrogen, alkyl, alkenyl, XR； • R is selected from alkyl, alenyl, alkynyl, cycloalkyl, all of which can be optionally substituted； • R is selected from the same moieties of R, plus alkoxycarbonyl. The preferred compounds are cyclosporine analogues carrying an ether functionality on the side chain of Leu-4.
