Compounds comprising a metal complex having the structure [X&mdashY&mdashZ-Mn+]p+.B are disclosed in which X is a histone deacetylase inhibitor, Mn+ is a DNA-binding heavy metal ion, Y is an aliphatic or aromatic spacer or is absent, and Z is a mono- or bi-dentate or chelating donor linker, or a bridging linker, P+ designates the charge on the complex ion, which may be positive, negative or absent and B is a counterion or is absent. The linker Z is labile and its metal complex X&mdashY&mdashZ-Mn+ is capable of being hydrolysed in-vivo. The compounds find application in the treatment of cancer.
