The invention relates to a combination which comprises: (a) a HDAI; and (b) an anti-metabolite, for simultaneous, concurrent, separate or sequential use, especially for use in the treatment of proliferative diseases, more specifically MDS or AML. The invention also relates to pharmaceutical compositions comprising such a combination and to a method of treating MDS or AML, in a mammal, particularly a human, with such a combination. The present invention further also relates to a commercial package or product comprising such a combination.