A series of 6,7-dihydro[1,3]thiazolo[5,4-c]pyridin-4(5H)-one derivatives, which are substituted in the 2-position by a substituted morpholin-4-yl moiety, being selective inhibitors of PI3 kinase enzymes, are accordingly of benefit in medicine, for example in the treatment of inflammatory, autoimmune, cardiovascular, neurodegenerative, metabolic, oncological, nociceptive or ophthalmic conditions.