THE INVENTION PROVIDES COMPOUNDS OF FORMULA (I) WHEREIN R4 IS A GROUP OF FORMULA (II) OR (IIIA) OR (IIIB) AND R1, R2, R3, R5, A, B AND X ARE AS DEFINED IN THE SPECIFICATION, A PROCESS FOR THEIR PREPARATION, PHARMACEUTICAL COMPOSITIONS CONTAINING THEM, A PROCESS FOR PREPARING PHARMACEUTICAL COMPOSITIONS, THEIR USE IN THERAPY AND INTERMEDIATES OF USE IN THEIR PREPARATION