A compound of Formula (I) ** Formula ** a tautomer or a stereoisomeric form, wherein each of Xa, Xb and Xc independently represents CH or N； -X1- represents - (CHR12) s-NR1-Xe-alkanediylC1-4- (SO2) p3- or - (CH2) s-O-Xe-alkanediylC1-4- (SO2) p3-； wherein each of said C1-4 alkanediyl moieties are optionally substituted with hydroxy or C1-4 hydroxyalkyl； -Xe- represents -C (R2) 2- or -C (>； = O) -； a represents -NR4-C (>； = O) - [C (R5b) 2] r- or -NR4-C (R5b) 2-C (>； = O) - or -C (>； = O) -NR4-C (R5b) 2-； b represents ** Formula ** where said ring b may contain extra bonds to form a bridged ring system selected from 2,5-diazabicyclo [2.2.2] octanyl, 3,8-diazabicyclo [3.2.1] octanyl, 3 , 6- diazabicyclo [3.1.1] heptanyl, 3,9-diazabicyclo [3.3.1] nonyl； Xd1 represents CH or N； Xd2 represents CH2 or NH； with the proviso that at least one of Xd1 and Xd2 represents nitrogen； c represents a bond, - [C (R5a) 2] m-, -C (>； = O) -, -O-, -NR5a'-, -SO2-, or -SO-； ** Formula ** the ring ** Formula ** represents phenyl or pyridyl； R 1 represents hydrogen, C 1-4 alkyl, C 2-4 alkenyl, C 2-4 alkynyl, C 1-4 cyanoalkyl, -C (>； = O) -C 1-4 alkyl, -C (>； = O) -C 1-4 haloalkyl, C 1-4 hydroxyalkyl, C 1-4 haloalkyl, C 1-4 alkyloxyC 1-4 alkyl, C 1-4 haloalkyloxyC 1-4 alkyl, -C (>； = O) NR7R8, -SO2-NR7R8, -SO2-R9, R11, alkyl C1-4 substituted with R11, -C (>； = O) -R11, or -C (>； = O) -C1-4-R11 alkyl； each R2 independently represents hydrogen, C1-4 alkyl, C1-4 alkyl substituted with C3-6 cycloalkyl, C1-4 hydroxyalkyl, C1-4 alkyloxy C1-4 alkyl, carboxyl, -C (>； = O) -O-C1-alkyl -4 where C1-4 alkyl is optionally substituted with C1-4 alkyloxy, -C (>； = O) -NH2, -C (>； = O) -NH (C1-4 alkyl) where C1-4 alkyl is optionally substituted with C1-4 alkyloxy, or -C (>； = O) -N (C1-4 alkyl) 2 where each C1-4 alkyl is optionally substituted with C1-4 alkyloxy； or R1 and R2 are taken together to form C1-4 alkanediyl or C2-4 alkenodiyl, each of said C1-4 alkanediyl and C2-4 alken
