5 or 8-substituted imidazo [1,5-a] pyridines as selective inhibitors of indoleamine and/or tryptophane 2,3-dioxygenases

A compound of Formula (IA) or (IB):

• or a stereoisomer thereof, or a pharmaceutically acceptable salt thereof,
• wherein:
• W is CH or N;
• Ring A is a C3-8 cycloalkyl ring or a monocyclic or bicyclic aromatic hydrocarbon ring or a monocyclic or bicyclic aromatic heterocyclic ring, said monocyclic or bicyclic aromatic hydrocarbon ring or monocyclic or bicyclic aromatic heterocyclic ring each having 5- to 10-ring members;
• Ring A is substituted with at least one substituent R1;
• R1, at each occurrence, is independently selected from hydrogen, halogen, cyano, OR4, NR4R5, COR4, SO2R4, C(═O)OR4, C(═O)NR4R5, N(R4)C(═O)R5, N(R4)C(═O)OR5, N(R4)C(O)NR4R5, N(R4)S(O)2NR4R5, C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein said C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl are each independently optionally substituted with at least one substituent R6;
• R2 and R3 are each independently selected from hydrogen, halogen, C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C3-8 cycloalkyl, C1-8 haloalkyl, aryl, heterocyclyl, heteroaryl, —CN, —OR4, or —SR4, wherein said C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C3-8 cycloalkyl, C1-8 haloalkyl, aryl, heterocyclyl, and heteroaryl are each independently optionally substituted with at least one substituted R6, provided that R2 and R3 are not both hydrogen;
• R4 is independently selected from hydrogen, C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C1-8 haloalkyl, C3-8 cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein said C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C1-8 haloalkyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl are each independently optionally substituted with 1 or 2 substituent R6;
• R5 is independently selected from hydrogen, C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C1-8 haloalkyl, C3-8 cycloalkyl, heterocyclyl, aryl, or heteroaryl, wherein said C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, C1-8 haloalkyl, C3-8 cycloalkyl, heterocyclyl, aryl, and heteroaryl are each independently optionally substituted with 1 or 2 substituent R6;
• R6 is selected from hydrogen, halogen, C1-4 haloalkyl, C1-4 alkyl, C2-8 alkenyl, C3-6 cycloalkyl, aryl, heteroaryl, heterocyclyl, alkynyl, oxo, —C1-4 alkyl-NRaRb, —CN, —Ra, —NRaRb, —CORa, —CO2Ra, —CONRaRb, —C(═NRa)NRbRc, nitro, —NRaCORb, —NRaCONRaRb, —NRaCO2Rb, —SO2Ra, —SO2aryl, —NRaSO2NRbRc, NRaSO2Rb, or —NRaSO2aryl, wherein said C1-4 alkyl, C1-4 haloalkyl, C3-6 cycloalkyl, aryl, heteroaryl, and heterocyclyl group are each independently optionally substituted by one, two or three substituents selected from halo, hydroxyl, C1-4 alkyl or C1-4 haloalkyl, wherein Ra, Rb, and Rc are each independently selected from H, C1-4 haloalkyl, C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl, C3-6 cycloalkyl, heterocyclyl, aryl, or heteroaryl;
• with the proviso that the compound is not (7-cyclopropylimidazo[1,5-a]pyridin-8-yl)(4-phenylcyclohexyl)methanol.