Safety and Efficacy Study of CC-486 in Subjects With Myelodysplastic Syndromes

Evaluate the safety and efficacy of CC-486 in Subjects with Myelodysplastic Syndromes who failed to achieve an objective response post iHMA treatment
Reason for removing the Combo arm: Due to difficulties with dose-finding, the durvalumab plus CC-486 combination arm is closed to enrollment.
Extension:
An Extension Phase (EP) has been added to allow subjects who are currently receiving oral azacitidine and who are demonstrating clinical benefit as assessed by the Investigator, to continue receiving oral azacitidine until the subject meets the criteria for study discontinuation.