Compounds of formula (1), pharmaceutically acceptable salts, solvates and in vivo hydrolysable esters thereof, have activity as pharmaceuticals, in particular as modulators of chemokine receptor (especially CXCR2) activity, and may be in the treatment (therapeutic or prophylactic) of conditions/diseases in human and non-human animals which are exacerbated or caused by excessive or unregulated production of chemokines.