R¹ is selected from: hydrogen, optionally-substituted C_1-6alkyl, optionally substituted C_1-6alkanoyl, optionally substituted aryl or optionally-substituted arylC_1-6alkyl;

R² is an optionally-substituted mono or bi-cyclic aromatic ring;

R³ is selected from a group of Formula (IIf):

R⁴ is selected from: hydrogen, optionally substituted C_1-6alkyl, optionally substituted aryl, C_1-3perfluoroalkyl, cyano, nitro, halo, R⁹O(CH₂)_m—, R⁹C(O)N(R¹⁰)—, R⁹R¹⁰NC(O)N(R¹⁰)(CH₂)_m—, R⁹S(O_n)(CH₂)_m— or R⁹R¹⁰NC(O)—(CR⁹R¹⁰)_t(CH₂)_m—;

R⁵ is a group of Formula (III):

R⁶ and R^6a are independently selected from hydrogen, fluoro, optionally substituted C_1-6alkyl, optionally-substituted aryl or optionally substituted arylC_1-6alkyl, or R⁶ and R^6a taken together and the carbon atom to which they are attached form a carbocyclic ring of 3-7 atoms, or R⁶ and R^6a taken together and the carbon atom to which they are attached form a carbonyl group;

or when A is not a direct bond the group

 forms a carbocyclic ring of 3-7 carbon atoms or a heterocyclic ring containing one or more heteroatoms;

R⁹ and R¹⁰ are independently selected from: hydrogen, hydroxy, optionally substituted C_1-6alkyl, optionally substituted aryl, optionally substituted arylC_1-6alkyl, an optionally substituted carbocyclic ring of 3-7 atoms, optionally substituted heterocyclyl, optionally substituted heterocyclylC_1-6alkyl or R⁹ and R¹⁰ taken together can form an optionally substituted ring of 3-9 atoms or R⁹ and R¹⁰ taken together with the carbon atom to which they are attached form a carbonyl group;

R¹⁷ is independently selected from: hydrogen, hydroxy, cyano or optionally substituted C_1-6alkyl;

R¹⁸ is a group of formula R^18a—C(R⁹R¹⁰)_0-1— wherein R^18a is selected from: R¹⁹OC(O)—, R⁹R¹⁰NC(O)—, R⁹R¹⁰N—, R⁹C(O)—, R⁹C(O)N(R¹⁰)—, R⁹R¹⁰NC(O)—, R⁹R¹⁰NC(O)N(R¹⁰)—, R⁹SO₂N(R¹⁰)—, R⁹R¹⁰NSO₂N(R¹⁰)—, R⁹C(O)O—, R⁹OC(O)—, R⁹R¹⁰NC(O)O—, R⁹O—, R⁹S(O_n)—, R⁹R¹⁰NS(O_n)—, hydrogen, optionally substituted C_1-6alkyl, optionally substituted heterocyclyl;

or R¹⁷ and R¹⁸ when taken together form an optionally substituted carbocyclic ring of 3-7 atoms or optionally substituted heterocyclyl;

R¹⁹ is selected from: hydrogen, optionally substituted C_1-6alky, optionally substituted aryl, optionally substituted arylC_1-6alkyl, optionally substituted C_3-7cycloalkyl, optionally substituted heterocyclyl or optionally substituted heterocyclyl C_1-6alkyl;

R²¹ and R²² are independently selected from hydrogen, optionally substituted C_1-6alkyl, optionally substituted C_3-7cycloalkyl, optionally substituted heterocyclyl, optionally substituted heterocyclylC_1-6alkyl, optionally substituted C_3-6alkenyl, optionally substituted C_3-6alkynyl, —(C_1-5alkyl)_aa-S(O_n)—(C_1-5alkyl)_bb-; R⁹R¹⁰NC_2-6alkyl, R⁹OC_2-6alkyl or R⁹R¹⁰NC(O)C_2-6alkyl, with the proviso that R⁹ and R¹⁰ independently or taken together are not optionally substituted aryl or optionally substituted arylC_1-6alkyl; or

R²¹ and R²² taken together form an optionally substituted non-aromatic heterocyclic ring;

A is selected from:

a direct bond;

optionally-substituted C_1-5alkylene wherein the optional substituents are independently selected from: optionally-substituted C_1-6alkyl optionally-substituted aryl or optionally substituted arylC_1-6alkyl;

a carbocyclic ring of 3-7 atoms;

a carbonyl group or —C(O)—C(R^dR^d)—, wherein R^d is independently selected from hydrogen and C_1-2alkyl;

G is selected from: hydrogen, halo, CN, NO₂, N, O, S(O_n),C(O), C(R⁹R¹⁰)_t, optionally substituted C_2-6alkenylene, optionally substituted C_2-6alkynylene, optionally substituted heterocyclyl or a direct bond to R¹⁸,

m is an integer from 0 to 4;

n is an integer from 0 to 2;

t is an integer from 0 to 4;

aa and bb are independently selected from 0 or 1 with the proviso that

(i) when G is hydrogen, halo, CN or NO₂ then R¹⁷ and R¹⁸ are both absent; and

(ii) when G is O, S(O_n), C(O) or C(R⁹R¹⁰)_t then G is substituted by a single group independently selected from the definition of R¹⁷ or R¹⁸ and when G is a direct bond to R¹⁸ then G is substituted by a single group selected from R¹⁸;

or a salt or pro-drug thereof.