Compounds of formula (IA) or (IB) are IKK inhibitors useful in the treatment of autoimmune and inflammatory diseases: wherein R7 is hydrogen or optionally substituted (C1-C6)alkyl; A is an optionally substituted aryl or heteroaryl of 5-13 ring atoms; Z is a radical of formula R1C(R2)(R3)NH-Y-L1-X1-(CH2)z- wherein R1 is a carboxylic acid group (-COOH), or an ester group which is hydrolysable by one or more intracellular esterase enzymes to a carboxylic acid group; and R2 and R3 independently represent the side chain of a natural or non-natural alpha amino acid but neither of R2 and R3 is hydrogen, or R2 and R3 taken together with the carbon atom to which they are attached form a C3-C7 cycloalkyl ring, and z, Y, L1 and X1 are as defined in the claims.