A compound of Formula (I), or a pharmaceutically acceptable salt or solvate thereof, wherein, R1 and R2 each independently represent H, halogen, CF3, C1-3 alkyl or C1-3 alkoxy; R3 represents C1-6 alkyl, C3-6 cycloalkyl, phenyl (optionally substituted by one or more substituents each independently selected from Ra) or Het (optionally substituted by one or more substituents each independently selected from OH, oxo, or C1-4 alkyl); R4 represents H or C1-3 alkyl; R5 represents C1-6 alkyl (optionally substituted by one or more substituents each independently selected from Rb), C3-6 cycloalkyl (optionally substituted by one or more substituents each independently selected from oxo or OH), or Het2 (optionally substituted by one or more substituents each independently selected from Rd); oxygen atom or 1 sulphur atom, or (c) 1 oxygen atom or 1 sulphur atom, (optionally substituted by one or more substituents each independently selected from OH, oxo or C1-4 alkyl); and R6 represents C1-3 alkyl (optionally substituted by one or more substituents each independently selected from Rf), C3-5 cycloalkyl (optionally substituted by one or more halogen), CN or halogen; where Rf represents halogen or phenyl: and compositions, processes for the preparation, and uses thereof, e.g. in the treatment of endometriosis or uterine fibroids.