Fused tricyclic imidazo pyrazines as modulators of TNF activity

A compound of formula (I) or an N-oxide thereof, or a pharmaceutically acceptable salt or solvate thereof, or a glucuronide derivative thereof, or a co-crystal thereof:

• wherein
• n represents an integer equal to 0 or 1;
• Y represents aryl or heteroaryl, any of which groups may be optionally substituted by one or more substituents selected from halogen, cyano, amino, C1-6 alkyl, C1-6 alkylsulphonyl, C1-6 alkoxy, trifluoromethoxy and difluoromethoxy;
• X represents oxygen, sulphur, S(O), or N(Rd), or a straight or branched C1-4 alkylene chain;
• R1 represents halogen, heteroaryl or (C3-7)heterocycloalkyl-heteroaryl any of which groups may be optionally substituted by one or more substituents selected from hydroxy, hydroxy(C1-6 alkyl) and C1-6alkoxy;
• R2 and R3 independently represent hydrogen, halogen or C1-6 alkyl;
• R4 represents hydrogen, hydroxy, halogen or trifluoromethyl;
• R5a represents hydrogen, hydroxy or —ORa;
• R5b represents hydrogen;
• and
• Ra represents C1-6 alkyl, aryl(C1-6)alkyl or heteroaryl(C1-6)alkyl, any of which groups may be optionally substituted by one or more substituents selected from C1-6 alkoxy, oxo and aminocarbonyl;
• and
• Rd represents hydrogen or C1-6 alkyl.