Study of Azacitidine With or Without Birinapant in Subjects With MDS or CMMoL

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) The primary purpose of this study is : -To compare the relative effect of azacitidine plus birinapant versus azacitidine plus placebo on response rate in patients with higher-risk MDS, secondary MDS or CMMoL. The secondary purpose of this study is to compare effect of azacitidine plus birinapant relative to azacitidine with placebo on: * Hematologic improvement * Relapse free survival * Time to respond * Change in transfusion requirements * Duration of response * Overall survival * Adverse events The exploratory objective of this study is to assess exploratory translational biomarkers for antitumor effects.