A compound of Formula (I) or a tautomer or a stereoisomeric form thereof, wherein X 1 represents wherein 'a' and 'b' indicate how variable X 1 is attached to the remainder of the molecule; R y represents halo; n represents 0, 1 or 2; X 2 represents which can be attached to the remainder of the molecule in both directions; or X 2 represents wherein 'c' and 'd' indicate how variable X 2 is attached to the remainder of the molecule; R 1 represents hydrogen; or C 1-6 alkyl optionally substituted with one substituent selected from the group consisting of Het 1 , -OR 3 , and -NR 4a R 4b ; R 2 represents hydrogen; methyl; or C 2-6 alkyl optionally substituted with one substituent selected from the group consisting of Het 1 , -OR 3 , and -NR 4a R 4b ; R 1a represents methyl or ethyl; R 3 represents hydrogen, C 1-4 alkyl, or -C 2-4 alkyl-O-C 1-4 alkyl; R 4a and R 4b are each independently selected from the group consisting of hydrogen and C 1-4 alkyl; R 5 represents hydrogen; methyl; or C 2-6 alkyl optionally substituted with one substituent selected from the group consisting of C 3-6 cycloalkyl, Het 1 , -NR 4a R 4b , and -OR 3 ; Het 1 represents a 4- to 7-membered monocyclic fully saturated heterocyclyl containing one or two heteroatoms each independently selected from O, S, and N, wherein said S-atom might be substituted to form S(=O) or S(=O) 2 ; wherein said heterocyclyl is optionally substituted with one or two substituents each independently selected from the group consisting of halo, cyano, and -O-C 1-4 alkyl; Y 1 represents -(CH 2 ) m - or -S-; m represents 1 or 2; or a pharmaceutically acceptable salt, or a solvate thereof. X 1 represents wherein 'a' and 'b' indicate how variable X 1 is attached to the remainder of the molecule; R y represents halo; n represents 0, 1 or 2; X 2 represents which can be attached to the remainder of the molecule in both directions; or X 2 represents wherein 'c' and 'd' indicate how variable X 2 is attached to the remainder of the molecule; R 1 represents hydrogen; or C 1-6 alkyl optionally substituted with one substituent selected from the group consisting of Het 1 , -OR 3 , and -NR 4a R 4b ; R 2 represents hydrogen; methyl; or C 2-6 alkyl optionally substituted with one substituent selected from the group consisting of Het 1 , -OR 3 , and -NR 4a R 4b ; R 1a represents methyl or ethyl; R 3 represents hydrogen, C 1-4 alkyl, or -C 2-4 alkyl-O-C 1-4 alkyl; R 4a and R 4b are each independently selected from the group consisting of hydrogen and C 1-4 alkyl; R 5 represents hydrogen; methyl; or C 2-6 alkyl optionally substituted with one substituent selected from the group consisting of C 3-6 cycloalkyl, Het 1 , -NR 4a R 4b , and -OR 3 ; Het 1 represents a 4- to 7-membered monocyclic fully saturated heterocyclyl containing one or two heteroatoms each independently selected from O, S, and N, wherein said S-atom might be substituted to form S(=O) or S(=O) 2 ; wherein said heterocyclyl is optionally substituted with one or two substituents each independently selected from the group consisting of halo, cyano, and -O-C 1-4 alkyl; Y 1 represents -(CH 2 ) m - or -S-; m represents 1 or 2; or a pharmaceutically acceptable salt, or a solvate thereof. <EOS>