Compound having the formula: ** (See formula) ** or a pharmaceutically acceptable salt thereof, in which: X1 is N, X2 is N, CH or C-CH3, R1 is an optionally substituted pyrazole-4-yl With 1 or 2 occurrences of R1a, R1a is chlorine, fluorine, aliphatic C1-8, - (CH2) 0-2 cycloaliphatic C3-6, - (CH2) 0-2-heterocyclic of 5 to 6 elements that presents up to two selected heteroatoms from nitrogen, oxygen or sulfur, -CN, -C (O) -C1-4 aliphatic, -C (O) NH (C1-4 aliphatic), -C (O) N (C1-4 aliphatic) 2, - C (O) O-aliphatic C1-4, -S (O) 2NH (aliphatic C1-4), - S (O) 2N (aliphatic C1-4) 2 or -S (O) 2-aliphatic C 1-4 , in which up to 3 non-contiguous carbon atoms of said aliphatic or cycloaliphatic of R1a can be substituted by -O-, -S- or -N (R1b) - and in which each of said aliphatic, cycloaliphatic or heterocyclic of R1a Optionally and independently replaced with up to 4 occurrences of JR, each JR is independently fluorine, oxo, - (CH2) 0-2CN, - (CH2) 0-2CF3 -C (O) R1b, -C (O) N (R1b ) 2, -C (O) O (R1b), -N (R1b) 2, -N (R1b) C (O) R1b, - (CH2) 0-2OR1b, phenyl or a heteroaryl of 5 to 6 elements, heterocycle of 4 to 6 elements or fused bicyclic heteroaryl or heterocyclyl of 9 to 11 elements, each of said heteroaryl or heterocyclyl rings having up to 3 atoms selected from nitrogen, oxygen or sulfur, in which each of said cycloaliphatic groups, phenyl , heteroaryl or heterocyclyl are optionally substituted with up to 2 R1c, each R1b is independently selected from hydrogen, C1-8 aliphatic, - (CH2) 0-1 C3-6 cycloaliphatic, - (CH2) 0-1heterocyclic C4-6 presenting up to two heteroatoms selected from N or O, or two R1b together with the atom to which they are attached form a heterocyclic ring of 5 to 6 elements, in which each aliphatic, cycloaliphatic or heterocyclic group is optionally substituted with up to three atoms of F or up to two groups -OH, -C1-2 alkyl or -O-C1-2 alkyl, each R1c is, in dependently, fluorine, chlorine, aliphatic C1-4, - (CH2) 0-2OH, -CN, -C (O) -aliphatic C1-4
