The invention concerns quinazoline and quinoline derivatives of Formula (I) wherein Q¹ includes a quinazoline or quinoline ring optionally substituted with a group such as halogeno, trifluoromethyl and cyano, or a group of the formula: Q³—X¹— wherein X¹ includes a direct bond and O and Q³ includes aryl, aryl-(1-6C)alkyl, heterocyclyl and heterocyclyl-(1-6C)alkyl; each of R², R³ and R⁵ is hydrogen or (1-6C)alkyl, provides that one of the parts of groups R² and R⁴ together, R³ and R⁴ together and R⁵ and R⁴ together forms a bond; R⁶ is an optionally substituted group selected from (2-6C) alkenyl, (2-6C) alkynyl, (3-7C)cycloalkyl and (3-7C) cycloalkenyl, or R⁶ is a substituted (1-6C) alkyl group; and Q² includes aryl and aryl-(1-3C)alkyl or a pharmaceutically-acceptable salt thereof; processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use in the prevention or treatment of T cell mediated diseases or medical conditions in a warm-blooded animal.