1-(2H)-ISOQUINOLONE DERIVATIVE

The present invention provides: a compound represented by the following formula (I): [wherein Y 1 and Y 4 represent a hydrogen atom or a halogen atom; either one of Y 2 and Y 3 represents -NR 1 R 2 , and the other represents a hydrogen atom or a halogen atom; X represents an aryl group or a heteroaryl group that may be substituted; R 1 represents a hydrogen atom, or a C 1-8 alkyl group that may be substituted; and R 2 represents a C 1-8 alkyl group that is substituted with one or more substituents, - COOR 3 , -COR 4 , -COSR 5 , -CONR 6 R 7 , -NR 22 R 23 , or -C=NR 24 R 25 ; or R 1 and R 2 , together with a nitrogen atom to which they are bonded, may form a 4- to 10-membered hetero ring containing at least one nitrogen atom (wherein the hetero ring may be substituted with one or more substituents selected from Group C)], a prodrug thereof, or a pharmaceutically acceptable salt thereof; and a pharmaceutical, a pharmaceutical composition, or the like, which comprises the compound.