This is a randomized double blind placebo controlled study of azacitidine with or without birinapant in subjects with higher risk Myelodysplastic syndrome, secondary MDS or myelomonocytic leukemia (CMMoL) who are naïve, to azacitidine therapy. Pre-clinical and mechanistic studies support that azacitidine may modulate pathways that enable birinapant-mediated anti-tumor activity.