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

key Inclusion Criteria:

* Morphologically confirmed diagnosis of MDS/CMMoL according to FAB or WHO classification, including RAEB-t and MDS/MPN
* International prognostic score-revised (IPSS-R) of \>3.5 (Intermediate, High or Very High)
* Previously untreated with hypomethylating agents for MDS/CMMoL
* Performance status of 0, 1 or 2 by the ECOG scale
* Adequate renal and liver function
* Female subjects of childbearing potential must have a negative serum pregnancy test at screening within 96 hours prior to the first study dose.
* Female subjects of childbearing potential and male subjects with partners of childbearing potential should ensure use of a highly effective method of birth control as defined by the investigator, for example, those which result in a low failure rate (i.e., less than 1% per year) when used consistently and correctly during the study and for a period of 3 months following the last dose of any drug administered during the study.

Key Exclusion Criteria:

* Relapsed or refractory to hypomethylating agents
* Acute myeloid leukemia (AML), except those patients with RAEB-t who are not candidates for intensive AML therapy.
* Participated in any interventional study within 4 weeks of randomization or 5 half lives (whichever is longer).
* Received any hematopoietic growth factors within 14 days prior to screening.
* Prior malignancy or secondary malignancy within the prior 2 years (except in situ cervical cancer, squamous cell carcinoma or basal cell carcinoma of the skin).
* known diagnosis of human immunodeficiency virus or chronic active Hep B or C.
* Uncontrolled hypertension
* Impaired cardiac function, uncontrolled cardiac arrhythmias despite medications, or clinically significant cardiac disease
* Lack of recovery of prior adverse events to Grade ≤1 severity (National Cancer Institute Common Terminology Criteria for Adverse Events version 4) (except alopecia) due to therapy administered prior to the initiation of study drug dosing.
* Nursing or pregnant.
* Known allergy or hypersensitivity to any of the formulation components
* Any concurrent disease and/or medical condition that, in the opinion of the Investigator, would prevent the subject's participation.
* History of cranial nerve palsy.
* Being treated with anti-TNF therapies or has been treated with an anti-TNF therapy within 5 half-lives of randomization.