Compound

A compound of formula (I):

• wherein:
• R represents hydrogen, halo, cyano, C1-4 haloalkyl, C1-4 haloalkoxy, or SO2NR5R6;
• R1a and R1b independently represent hydrogen or halo;
• R2 represents hydrogen, halo, cyano, C1-4 alkyl, C1-4 alkoxy or C1-4 haloalkoxy;
• R3 represents, halo, cyano, C1-4 alkyl, or C1-4 hydroxyalkyl;
• R4 represents, hydrogen or C1-4 alkyl;
• X represents CH or N;
• Y represents CH or N;
• R5 and R6 independently represent hydrogen or C1-4 alkyl;
• or a pharmaceutically acceptable salt thereof.