A compound of formula or a pharmaceutically acceptable salt thereof, wherein: A is C 2 -C 9 -heterocycloalkyl, C 3 -C 12 -cycloalkyl, C 6 -C 14 -aryl or C 1 -C 13 -heteroaryl; R 1 is hydrogen, C 1 -C 6 -alkyl, halo-C 1 -C 6 -alkyl, cyano-C 1 -C 6 -alkyl, hydroxy-C 1 -C 6 -alkyl, amino-C 1 -C 6 -alkyl, C 1 -C 6 -alkyl-NH-C 1 -C 6 -alkyl-, (C 1 -C 6 -alkyl) 2 N-C 1 -C 6 -alkyl-, amino-C 1 -C 6 -alkyl-O-C 1 -C 6 -alkyl, C 1 -C 6 -alkyl-NH-C 1 -C 6 -alkyl-O-C 1 -C 6 -alkyl-, (C 1 -C 6 -alkyl) 2 N-C 1 -C 6 -alkyl-O-C 1 -C 6 -alkyl- or C 3 -C 12 -cycloalkyl; R 2 is hydrogen, hydroxy, carboxy, amino, C 1 -C 6 -alkyl-NH-, C 1 -C 6 -alkyl-C -NH-, (C 1 -C 6 -alkyl) 2 N-, amino-C 1 -C 6 -alkyl, hydroxy-C 1 -C 6 -alkyl, oxo, halogen, guanidino-C 1 -C 6 -alkyl, guanidino-C 1 -C 6 -alkyl-CH(NH 2)-C -, guanidino-C 1 -C 6 -alkyl-CH(NH 2)-C -NH-, (C 1 -C 6 -alkyl) 2 N-C 2 -C 6 -alkenyl-NH-, C 1 -C 6 -alkyl-NH-C 2 -C 6 -alkenyl-NH-, amino-C 2 -C 6 -alkenyl-NH-, C 1 -C 6 -alkylimidoyl-NH-C 1 -C 6 -alkyl; C 1 -C 6 -alkyl or a group each of R 3, R 4 and R 5 is independently hydrogen or hydroxy; R 6 is hydrogen, halogen, C 1 -C 6 -alkyl, halo-C 1 -C 6 -alkyl, hydroxy-C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, NO 2, CN, C 3 -C 12 -cycloalkyl, hydroxy-C 1 -C 6 -alkoxy-C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy or alkoxy-C 1 -C 6 -alkyl; R 7 and R 13 are each independently hydrogen, halogen or C 1 -C 6 -alkyl; each of R 8, R 9, R 10, R 11 and R 12 is independently hydrogen, halogen, C 1 -C 6 -alkoxycarbonyl-C 1 -C 6 -alkoxy, amino, C 1 -C 6 -alkyl-NH-, (C 1 -C 6 -alkyl) 2 N-, hydroxy, C 1 -C 6 -alkoxy, C 1 -C 6 -alkylsulfanyl, C 1 -C 6 -alkylsulfonyloxy, C 3 -C 12 -cycloalkyl-C 1 -C 6 -alkoxy, halo-C 1 -C 6 -alkoxy, C 6 -C 14 -aryl-C 1 -C 6 -alkoxy, C 1 -C 13 -heteroaryloxy, C 1 -C 13 -heteroaryl-C 1 -C 6 -alkoxy, cyano-C 1 -C 6 -alkoxy, C 3 -C 12 -cycloalkyloxy, C 2 -C 6 -alkynyloxy, C 1 -C 6 -alkoxy-C 2 -C 6 -alkynyloxy, cyano-C 3 -C 12 -cycloalkyloxy, cyano-C 3 -C 12 -cycloalkyl-C 1 -C 6 -alkoxy, amino-C 2 -C 6 -alkynyloxy, hydroxy-C 2 -C 6 -alkynyloxy, halo-C 1 -C 6 -alkyl, sulfamoyl, C 1 -C 6 -alkylsulfamoyl, C 1 -C 6 -alkyl, amino-C 1 -C 6 -alkoxy-C 2 -C 6 -alkynyloxy or amino-C 1 -C 6 -alkoxy; R 14 is hydrogen, halogen or C 1 -C 6 -alkyl; R 15 and R 16 are each independently hydrogen, oxo or hydroxy; B is C 2 -C 9 -heterocycloalkyl; and L is a covalent bond, carbonyl, -NH-C - or -C -NH-. A is C 2 -C 9 -heterocycloalkyl, C 3 -C 12 -cycloalkyl, C 6 -C 14 -aryl or C 1 -C 13 -heteroaryl; R 1 is hydrogen, C 1 -C 6 -alkyl, halo-C 1 -C 6 -alkyl, cyano-C 1 -C 6 -alkyl, hydroxy-C 1 -C 6 -alkyl, amino-C 1 -C 6 -alkyl, C 1 -C 6 -alkyl-NH-C 1 -C 6 -alkyl-, (C 1 -C 6 -alkyl) 2 N-C 1 -C 6 -alkyl-, amino-C 1 -C 6 -alkyl-O-C 1 -C 6 -alkyl, C 1 -C 6 -alkyl-NH-C 1 -C 6 -alkyl-O-C 1 -C 6 -alkyl-, (C 1 -C 6 -alkyl) 2 N-C 1 -C 6 -alkyl-O-C 1 -C 6 -alkyl- or C 3 -C 12 -cycloalkyl; R 2 is hydrogen, hydroxy, carboxy, amino, C 1 -C 6 -alkyl-NH-, C 1 -C 6 -alkyl-C -NH-, (C 1 -C 6 -alkyl) 2 N-, amino-C 1 -C 6 -alkyl, hydroxy-C 1 -C 6 -alkyl, oxo, halogen, guanidino-C 1 -C 6 -alkyl, guanidino-C 1 -C 6 -alkyl-CH(NH 2)-C -, guanidino-C 1 -C 6 -alkyl-CH(NH 2)-C -NH-, (C 1 -C 6 -alkyl) 2 N-C 2 -C 6 -alkenyl-NH-, C 1 -C 6 -alkyl-NH-C 2 -C 6 -alkenyl-NH-, amino-C 2 -C 6 -alkenyl-NH-, C 1 -C 6 -alkylimidoyl-NH-C 1 -C 6 -alkyl; C 1 -C 6 -alkyl or a group each of R 3, R 4 and R 5 is independently hydrogen or hydroxy; R 6 is hydrogen, halogen, C 1 -C 6 -alkyl, halo-C 1 -C 6 -alkyl, hydroxy-C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, NO 2, CN, C 3 -C 12 -cycloalkyl, hydroxy-C 1 -C 6 -alkoxy-C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy or alkoxy-C 1 -C 6 -alkyl; R 7 and R 13 are each independently hydrogen, halogen or C 1 -C 6 -alkyl; each of R 8, R 9, R 10, R 11 and R 12 is independently hydrogen, halogen, C 1 -C 6 -alkoxycarbonyl-C 1 -C 6 -alkoxy, amino, C 1 -C 6 -alkyl-NH-, (C 1 -C 6 -alkyl) 2 N-, hydroxy, C 1 -C 6 -alkoxy, C 1 -C 6 -alkylsulfanyl, C 1 -C 6 -alkylsulfonyloxy, C 3 -C 12 -cycloalkyl-C 1 -C 6 -alkoxy, halo-C 1 -C 6 -alkoxy, C 6 -C 14 -aryl-C 1 -C 6 -alkoxy, C 1 -C 13 -heteroaryloxy, C 1 -C 13 -heteroaryl-C 1 -C 6 -alkoxy, cyano-C 1 -C 6 -alkoxy, C 3 -C 12 -cycloalkyloxy, C 2 -C 6 -alkynyloxy, C 1 -C 6 -alkoxy-C 2 -C 6 -alkynyloxy, cyano-C 3 -C 12 -cycloalkyloxy, cyano-C 3 -C 12 -cycloalkyl-C 1 -C 6 -alkoxy, amino-C 2 -C 6 -alkynyloxy, hydroxy-C 2 -C 6 -alkynyloxy, halo-C 1 -C 6 -alkyl, sulfamoyl, C 1 -C 6 -alkylsulfamoyl, C 1 -C 6 -alkyl, amino-C 1 -C 6 -alkoxy-C 2 -C 6 -alkynyloxy or amino-C 1 -C 6 -alkoxy; R 14 is hydrogen, halogen or C 1 -C 6 -alkyl; R 15 and R 16 are each independently hydrogen, oxo or hydroxy; B is C 2 -C 9 -heterocycloalkyl; and L is a covalent bond, carbonyl, -NH-C - or -C -NH-.