Abstract: Compounds of the formula (I), wherein R1 is aryl or biaryl; R2 is aryl-lower alkyl, biaryl-lower alkyl, benzo-fused cycloalkyl, cycloalkyl-lower alkyl, bicycloalkyl-lower alkyl, aryloxy-lower alkyl, or aryl-C2-C7-alkyl in which C2-C7-alkyl is interrupted by Y; Y is O, S, SO, SO2, CO or NR6; R3 is hydrogen or lower alkyl; or R2 and R3 combined are C2-C7-alkylene or C2-C7-alkylene interrupted by Y; R4 is hydrogen or lower alkyl; R5 is hydrogen, optionally substituted lower alkyl, aryl-lower alkyl, biaryl-lower alkyl, cycloalkyl-lower alkyl, bicycloalkyl-lower alkyl, aryloxy-lower alkyl, or aryl-C2-C7-alkyl in which C2-C7-alkyl is interrupted by Y; R6 is hydrogen, lower alkyl or aryl-lower alkyl; and pharmaceutically acceptable salts thereof, which are useful as cysteine cathepsin inhibitors.

Abstract: N-terminal substituted dipeptide nitriles as defined are useful as inhibitors of cysteine cathepsins, e.g. cathepsins B, K, L and S, and can be used for the treatment of cysteine cathepsin dependent diseases and conditions, including inflammation, rheumatoid arthritis, osteoarthritis, osteoporosis, tumors (especially tumor invasion and tumor metastasis), coronary disease, atherosclerosis (including atherosclerotic plaque rupture and destabilization). Particular dipeptide nitriles are compounds of formula I, or physiologically-acceptable and -cleavable esters or a salts thereof wherein: the symbols are as defined. In particular it has been found that by appropriate choice of groups R, R2, R3, R4, R5, X1, Y and L, the relative selectivity of the compounds as inhibitors of the various cysteine cathepsin types, e.g. cathepsins B, K, L and S may be altered, e.g. to obtain inhibitors which selectively inhibit a particular cathepsin type or combination of cathepsin types.