9. Continued from 8) : Since the effect of both avelumab and 5-azacytidine may be delayed, use of one hydroxyurea for patients with rapidly proliferative disease is allowed before the start of study therapy and will not require a washout. Concurrent therapy for CNS prophylaxis or continuation of therapy for controlled CNS disease is permitted. Patients with CNS disease or leukemic brain metastasis must have been treated locally and be clinically stable for at least 2 weeks prior to enrollment and have no ongoing neurological symptoms that are related to the CNS disease (sequelae that are a consequence of the treatment of the CNS disease are acceptable).