A compound of formula or a salt thereof: (wherein the symbols are as defined below: -X-: a group of formula; A: chloro, ethyl or isopropyl; R 1: phenyl in which the carbon at the 4-position is substituted with -W-Y-Z and the carbon at the 3-position may be substituted with a group selected from the group consisting of halogen, R 00 and -O-R 00; Z: a non-aromatic heterocyclic ring which may be substituted with one or more R 00; R 00: linear or branched C 1-6 alkyl which may be substituted with one or more halogens; -W-: a bond, piperidine-1,4-diyl, or piperazine-1,4-diyl; -Y-: a bond;; R 2: (i) cycloalkyl which may be substituted with one or more groups selected from the group consisting of N(C 1-6 linear or branched alkyl) 2, C 1-6 linear or branched alkyl, -COO-C 1-6 linear or branched alkyl, -OH, -COOH, -CONH-R ZB and morpholinyl, or, (ii) a non-aromatic heterocyclic ring which may be substituted with one or more groups selected from the group consisting of C 1-6 linear or branched alkyl, -CO- C 1-6 linear or branched alkyl, oxo, -CO-R ZB and benzyl; R ZB: phenyl which may be substituted with a group selected from the group consisting of halogen and -O-linear or branched C 1-6 alkyl; R 3: -H. -X-: a group of formula; A: chloro, ethyl or isopropyl; R 1: phenyl in which the carbon at the 4-position is substituted with -W-Y-Z and the carbon at the 3-position may be substituted with a group selected from the group consisting of halogen, R 00 and -O-R 00; Z: a non-aromatic heterocyclic ring which may be substituted with one or more R 00; R 00: linear or branched C 1-6 alkyl which may be substituted with one or more halogens; -W-: a bond, piperidine-1,4-diyl, or piperazine-1,4-diyl; -Y-: a bond;; R 2: (i) cycloalkyl which may be substituted with one or more groups selected from the group consisting of N(C 1-6 linear or branched alkyl) 2, C 1-6 linear or branched alkyl, -COO-C 1-6 linear or branched alkyl, -OH, -COOH, -CONH-R ZB and morpholinyl, or, (ii) a non-aromatic heterocyclic ring which may be substituted with one or more groups selected from the group consisting of C 1-6 linear or branched alkyl, -CO- C 1-6 linear or branched alkyl, oxo, -CO-R ZB and benzyl; R ZB: phenyl which may be substituted with a group selected from the group consisting of halogen and -O-linear or branched C 1-6 alkyl; R 3: -H. phenyl in which the carbon at the 4-position is substituted with -W-Y-Z and the carbon at the 3-position may be substituted with a group selected from the group consisting of halogen, R 00 and -O-R 00; Z: a non-aromatic heterocyclic ring which may be substituted with one or more R 00; R 00: linear or branched C 1-6 alkyl which may be substituted with one or more halogens; -W-: a bond, piperidine-1,4-diyl, or piperazine-1,4-diyl; -Y-: a bond;; R 2: (i) cycloalkyl which may be substituted with one or more groups selected from the group consisting of N(C 1-6 linear or branched alkyl) 2, C 1-6 linear or branched alkyl, -COO-C 1-6 linear or branched alkyl, -OH, -COOH, -CONH-R ZB and morpholinyl, or, (ii) a non-aromatic heterocyclic ring which may be substituted with one or more groups selected from the group consisting of C 1-6 linear or branched alkyl, -CO- C 1-6 linear or branched alkyl, oxo, -CO-R ZB and benzyl; R ZB: phenyl which may be substituted with a group selected from the group consisting of halogen and -O-linear or branched C 1-6 alkyl; R 3: -H. (i) cycloalkyl which may be substituted with one or more groups selected from the group consisting of N(C 1-6 linear or branched alkyl) 2, C 1-6 linear or branched alkyl, -COO-C 1-6 linear or branched alkyl, -OH, -COOH, -CONH-R ZB and morpholinyl, or, (ii) a non-aromatic heterocyclic ring which may be substituted with one or more groups selected from the group consisting of C 1-6 linear or branched alkyl, -CO- C 1-6 linear or branched alkyl, oxo, -CO-R ZB and benzyl;