The invention provides a compound which is an amide of the formula (2): or a salt or stereoisomer thereof; wherein: R 7 is selected from chlorine and fluorine; R 3 , R 4 , R 5 and R 6 are each independently selected from hydrogen, fluorine and chlorine; n is 0, 1 or 2; Q 1 is selected from C(=O), S(=O) and SO 2 ; A is absent or is NR 2 ; R 1 is selected from: - hydrogen; - an optionally substituted C 1-6 non-aromatic hydrocarbon group; and - 3- to 7-membered non-aromatic carbocyclic and heterocyclic rings containing one or two heteroatom ring members selected from O, N and S, and bridged bicyclic heterocyclic rings of seven to nine ring members of which one or two are nitrogen atoms, the carbocyclic and heterocyclic rings and bridged bicyclic heterocyclic rings being optionally substituted; R 2 is selected from hydrogen and C 1-4 alkyl; or NR 1 R 2 forms an optionally substituted 4- to 7-membered non-aromatic nitrogen-containing heterocyclic ring optionally containing a second heteroatom ring member selected from nitrogen and oxygen; with the provisos that: (i) no more than two of R 3 to R 6 are other than hydrogen; and (ii) when R 7 and R 6 are both fluorine, then one of R 3 to R 5 is chlorine or fluorine and/or R 1 -A-Q 1 is selected from ethylsulfonyl and isopropylsulfonyl. Also provided are pharmaceutical compositions containing the compounds and their therapeutic uses.