The present invention relates to the use of an HDAC inhibitor, especially an HDAC inhibitor of formula (I) wherein the radicals and symbols have the meanings as defined in the specification, for the preparation of a medicament for the treatment of myeloma, in particular, multiple myeloma, especially myeloma which is resistant to conventional chemotherapy； to a combination comprising an HDAC inhibitor and a compound effecting apoptosis of myeloma cells, preferably bortezomib, for simultaneous, separate or sequential use； to methods of treating myeloma； and to a pharmaceutical composition comprising said combination.
