There are disclosed compound of Formula (I) or (II) wherein A1, A2, A3, A4and A5, which may be the same or different, represent N or CR1, R9 represents - L -R3, in which L is a single bond or a linker group and R3 represents hydrogen or a substituent and in addition, when an adjacent pair of A1 - A4 each represent CR1, then the adjacent carbon atoms, together with their substituents may form a ring B, when A5 represents CR1, then A5 and N - R9, together with their substituents may form a ring C, or a harmaceutically acceptable salt thereof, in the manufacture of a medicament for the therapeutic and/or prophylactic treatment of Duchenne muscular dystrophy, Becker muscular dystrophy or cachexia.