Among drugs that have demonstrated to be active as a single agent in MDS and have preclinical potential additive or synergistic activity with AZA are Histone deacetylase (HDAC) inhibitors including Valproic acid, Lenalidomide and idarubicin. Phase I studies have already been conducted or are being conducted combining those agents to demethylating agents, showing a low toxicity profile and significant responses in high risk MDS. In this phase II randomized trial, we want to identify the most promising combination of Azacitidine and another drug (among 3 drugs: Valproic acid, Lenalidomide and Idarubicin) in higher risk MDS, by comparison to Azacitidine alone. Of note, based on efficacy and toxicity, one or several combinations may be stopped, and others, previously tested in phase I trials, included after protocol amendment.