The present disclosure relates to certain (2 S )- N -[(1 S )-1-cyano-2-phenylethyl]-1,4-oxazepane-2-carboxamide compounds (including pharmaceutically acceptable salts thereof), that inhibit dipeptidyl peptidase 1 (DPP1) activity, to their utility in treating and/or preventing clinical conditions including respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), to their use in therapy, to pharmaceutical compositions containing them and to processes for preparing such compounds.