The main objective of this phase II randomized trial is to identify, among 3 combinations of Azacitidine and another drug evaluated simultaneously, the most promising combination(s) for the treatment of higher risk MDS (IPSS Int-2 and High) compared to Azacitidine alone. The 3 tested drugs in combination with Azacitidine are: Valproic Acid, Lenalidomide and Idarubicin.