A compound represented by the formula: wherein R 1 is a group represented by the formula: -COR 2 wherein R 2 is (a) a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms; (b) a C 1-6 alkoxy group; or (c) an amino group optionally mono- or di-substituted by C 1-6 alkyl group(s); R 3 is a C 1-6 alkyl group optionally substituted by halogen atom(s), or an optionally substituted C 3-6 cycloalkyl group; R 4a and R 4b are independently a hydrogen atom or a substituent; X is O, CO, CR 5a R 5b wherein R 5a and R 5b are independently a hydrogen atom or a substituent, NR 5c wherein R 5c is a hydrogen atom or an optionally substituted C 1-6 alkyl group, S, SO, or S 2; ring A is an optionally further substituted 5- or 6-membered aromatic ring; for ring P and ring Q, ring P is an optionally further substituted 5-membered aromatic ring, ring Q is an optionally further substituted 6-membered ring, and ring P and ring Q are fused to form an optionally further substituted bicyclic aromatic ring, or ring P is an optionally further substituted 5-membered non-aromatic ring, ring Q is an optionally further substituted 6-membered aromatic ring, and ring P and ring Q are fused to form an optionally further substituted bicyclic non-aromatic ring; and R 6 is an optionally substituted C 1-6 alkyl group or an optionally substituted C 3-6 cycloalkyl group, or a pharmacologically acceptable salt thereof. R 1 is a group represented by the formula: -COR 2 wherein R 2 is (a) a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms; (b) a C 1-6 alkoxy group; or (c) an amino group optionally mono- or di-substituted by C 1-6 alkyl group(s); (a) a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms; (b) a C 1-6 alkoxy group; or (c) an amino group optionally mono- or di-substituted by C 1-6 alkyl group(s); R 3 is a C 1-6 alkyl group optionally substituted by halogen atom(s), or an optionally substituted C 3-6 cycloalkyl group; R 4a and R 4b are independently a hydrogen atom or a substituent; X is O, CO, CR 5a R 5b wherein R 5a and R 5b are independently a hydrogen atom or a substituent, NR 5c wherein R 5c is a hydrogen atom or an optionally substituted C 1-6 alkyl group, S, SO, or S 2; ring A is an optionally further substituted 5- or 6-membered aromatic ring; for ring P and ring Q, ring P is an optionally further substituted 5-membered aromatic ring, ring Q is an optionally further substituted 6-membered ring, and ring P and ring Q are fused to form an optionally further substituted bicyclic aromatic ring, or ring P is an optionally further substituted 5-membered non-aromatic ring, ring Q is an optionally further substituted 6-membered aromatic ring, and ring P and ring Q are fused to form an optionally further substituted bicyclic non-aromatic ring; and ring P is an optionally further substituted 5-membered aromatic ring, ring Q is an optionally further substituted 6-membered ring, and ring P and ring Q are fused to form an optionally further substituted bicyclic aromatic ring, or ring P is an optionally further substituted 5-membered non-aromatic ring, ring Q is an optionally further substituted 6-membered aromatic ring, and ring P and ring Q are fused to form an optionally further substituted bicyclic non-aromatic ring; and R 6 is an optionally substituted C 1-6 alkyl group or an optionally substituted C 3-6 cycloalkyl group, or a pharmacologically acceptable salt thereof.