The invention provides combinations comprising (or consisting essentially of) one or more ancillary compound(s) and a compound of the formula (I): or salts, tautomers, solvates and N-oxides thereof； wherein R1 is hydroxy or hydrogen； R2 is hydroxy； methoxy or hydrogen； provided that at least one of R1 and R2 is hydroxy； R3 is selected from hydrogen； halogen； cyano； optionally substituted C1-5 hydrocarbyl and optionally substituted C1-5 hydrocarbyloxy； R4 is selected from hydrogen； a group &mdash；(O)n&mdash；R7 where n is 0 or 1 and R7 is an optionally substituted acyclic C1-5 hydrocarbyl group or a monocyclic carbocyclic or heterocyclic group having 3 to 7 ring members； halogen； cyano； hydroxy； amino； and optionally substituted mono- or di-C1-5 hydrocarbyl-amino； or R3 and R4 together form a monocyclic carbocyclic or heterocyclic ring of 5 to 7 ring members； and NR5R6 forms an optionally substituted bicyclic heterocyclic group having 8 to 12 ring members of which up to 5 ring members are heteroatoms selected from oxygen, nitrogen and sulphur. The combinations have activity as Hsp90 and/or glycogen synthase kinase-3 and/or cyclin dependent kinase and/or aurora kinase inhibitors.
