Arene ruthenium (II) compounds and their use in cancer therapy

A ruthenium (II) compound of formula (I): or a solvate or prodrug thereof, wherein: R1, R1, R3, R4, R5 and R6 are independently selected from H, C1-7 alkyl, C5-20 aryl, C3-20 heterocyclyl, halo, ester, amido, acyl, sulfo, sulfonamido, ether, thioether, azo, amino, or R1 and R2 together with the ring to which they are attached form a saturated or unsaturated carbocyclic or heterocyclic group containing up to three 3- to 8- membered carbocyclic or heterocyclic rings, wherein each carbocyclic or heterocyclic ring may be fused to one or more other carbocyclic or heterocyclic rings; X is a neutral or negatively charged N- or S- donor ligand; Y is a counterion; m is 0 or 1; q is 1, 2 or 3; C' is C1-12 alkylene bound to two A groups; p is 0 or 1 and r is 1 when p is 0 and r is 2 when p is 1; and A and B are each independently O-donor, N-donor or S-donor ligands, and may be connected to one another. The compounds are used in cancer therapy.