Carboxamide derivatives

A compound of formula (I):

• or a pharmaceutically acceptable salt thereof, wherein
• R1 is (C3-C6)alkyl or (C3-C6)cycloalkyl;
• R2 is methyl;
• R3 is selected from (C6-C10)branched alkyl, (C6-C10)branched alkenyl, (C5-C8)cycloalkenyl, (C5-C8)cycloalkyl, or Met;
• wherein the (C5-C8)cycloalkenyl or (C5-C8)cycloalkyl is unsubstituted or is substituted by one, two, three or four substituents R4;
• and wherein Met is substituted by one, two, three or four substituents R4;
• each R4 is independently selected from halo, (C1-C4)alkyl, halo(C1-C4)alkyl, (C1-C4)alkoxy, or halo(C1-C4)alkoxy;
• or
• two R4 groups, when attached to the same carbon atom, may be taken together with the carbon atom to which they are attached to form a cyclopentyl, tetrahydrofuran or dioxolane ring;
• wherein Het is a 5 or 6 membered fully saturated or partially saturated heterocyclic ring comprising a) 1 oxygen atom in the 2- or 3-position, or b) 2 oxygen atoms in the 2- and 5-, or 2- and 6-positions, wherein the numbering is relative to the point of attachment;
• and
• (C5-C8)cycloalkyl may be a monocyclic ring or a bridged ring system containing 5, 6, 7 or 8 carbon atoms.