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.