Indole derivative having antagonist activity of PGD2.

A compound of generic formula (I): wherein ring A is a benzene ring; ring B is a ring of formula: R1, R2, R3, R4 and R5 are independently a hydrogen atom, a halogen atom, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted cycloalkyl, optionally substituted cycloalkenyl, hydroxy, alkyloxy, optionally substituted alkenyloxy, optionally substituted alkynyloxy, optionally substituted cycloalkyloxy, optionally substituted cycloalkyloxy, optionally substituted, mercapto, alkylthio, optionally substituted alkenylthio, optionally substituted alkynylthio, optionally substituted alkylsulfinyl, optionally substituted alkylsulfonyl, optionally substituted alkylsulfonyloxy, optionally substituted cycloalkylthio optionally , optionally substituted cycloalkylsulfinyl, cycloalkylsulfonyl optionally substituted cycloalkylsulfonyloxy optionally substituted, optionally substituted cycloalkenylthio, ci I cloalquenilsulfinilo optionally substituted cycloalkenylsulfonyl optionally substituted cicloalquenilsulfoniloxi optionally substituted, optionally substituted amino, acyl, alkyloxycarbonyl, optionally substituted alkylcarbonyl, optionally substituted alkynyloxycarbonyl, optionally substituted, optionally substituted carbamoyl, sulfamoyl optionally substituted, cyano, nitro, optionally substituted aryl, optionally substituted aryloxy, arylthio, optionally substituted arylsulfinyl, optionally substituted arylsulfonyl, optionally substituted arylsulfonyloxy, optionally substituted heteroaryl, optionally substituted heteroaryloxy, optionally substituted heteroarylthio, optionally substituted heteroarylsulfinyl optionally substituted heteroarylsulfonyl, optionally substituted optionally substituted heteroarylsulfonyloxy or a nonaromatic heterocyclic group optionally substituted; R6 is alkyloxy C2-C6 alkyloxy C1-C6 alkyl, C2-C6 alkenyloxy, optionally substituted C2-C6 alkynyloxy optionally substituted C3-C6 cycloalkyloxy optionally substituted cycloalkyloxy, C3-C6 optionally substituted aryloxy, optionally substituted heteroaryloxy, optionally substituted alkylthio C2-C6 alkyl, C1-C6 substituted, alkenylthio C2-C6, optionally substituted C2-C6 alkynylthio optionally substituted cycloalkylthio C3-C6 optionally substituted cycloalkenylthio C3-C6 optionally substituted arylthio, optionally substituted or heteroarylthio optionally substituted; R7 is independently a halogen atom, alkyl optionally substituted, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted cycloalkyl, optionally substituted cycloalkenyl, hydroxy, alkyloxy, optionally substituted alkenyloxy, optionally substituted alkynyloxy, optionally substituted cycloalkyloxy, optionally substituted cycloalkyloxy, optionally substituted, mercapto, alkylthio, optionally substituted alkenylthio, optionally substituted alkynylthio, optionally substituted alkylsulfinyl, optionally substituted alkylsulfonyl, optionally substituted alkylsulfonyloxy, optionally substituted cycloalkylthio optionally, substituted cycloalkylsulfinyl optionally substituted cycloalkylsulfonyl, optionally substituted cycloalkylsulfonyloxy optionally substituted cycloalkenylthio optionally substituted cycloalkenylsulfinyl optionally substituted, cycloalkenylsulfonyl opcionalmen I substituted cicloalquenilsulfoniloxi optionally substituted, optionally substituted amino, acyl, alkyloxycarbonyl, optionally substituted alkylcarbonyl, optionally substituted alkynyloxycarbonyl, optionally substituted, optionally substituted carbamoyl, sulfamoyl optionally substituted, cyano, nitro, optionally substituted aryl, optionally substituted aryloxy, arylthio, optionally substituted arylsulfinyl optionally substituted arylsulfonyl, optionally substituted arylsulfonyloxy, optionally substituted optionally substituted heteroaryl, optionally substituted heteroaryloxy, optionally substituted heteroarylthio I heteroarylsulfinyl optionally substituted heteroarylsulfonyl, optionally substituted optionally substituted heteroarylsulfonyloxy or a nonaromatic heterocyclic group optionally substituted; R8 is independently a halogen atom, alkyl optionally substituted, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted cycloalkyl, optionally substituted alkyloxy, oxo, optionally substituted aryl, optionally substituted heteroaryl or non-aromatic heterocyclic group optionally substituted; R9 is carboxy, optionally substituted alkyloxycarbonyl, optionally substituted carbamoyl or carboxy group equivalent, in which the carboxy group equivalent is selected from -CONHCN, -CONHOH, - CONHOMe, -CONHOt-Bu, -CONHOCH2Ph, -SO3H, -SO2NH2, -SO2NHMe, -NHCONH2, -NHCONMe 2, - P (= O) (OH) 2, -P (= O) (OH) (OEt), -P (= O) (OH) NH2, -P (= O) (OH) NHMe, -CONHSO2P -SO2NHCOMe, -SO2NHCOPh and formulas: L3 is optionally substituted alkylene which may contain one or two heteroatoms; n is 0, 1 or 2; and is 0, 1, 2 or 3; with the proviso that R9 is not optionally substituted carbamoyl when all of R1, R2, R3, R4 and R5 are a hydrogen atom; a pharmaceutically acceptable salt or a hydrate thereof