Sabatolimab as a Treatment for Patients With Acute Myeloid Leukemia and Presence of Measurable Residual Disease After Allogeneic Stem Cell Transplantation.

Inclusion Criteria: * Signed informed consent must be obtained prior to participation in the study. * At the date of signing the informed consent form (ICF), eligible participants must be ≥ 18 years for the adult cohorts; and ≥ 12 years old but \< 18 years old for the adolescent cohort (cohort 5), which will open after completion of Safety Run-in. * Participants in complete remission (\< 5% bone marrow blasts, absence of circulating blasts, and absence of extramedullary disease) with MRD positivity by local assessment or by central assessment where required (e.g., USA sites), any time at ≥ Day 60 after aHSCT * Diagnosis of AML/secondary AML and received one prior aHSCT performed to control AML * Ability to provide a fresh bone marrow aspirate sample collected within 28 days from enrollment/randomization, and immediately shipped to a Novartis designated central laboratory for MRD testing. * Systemic GvHD (graft versus host disease) prophylaxis or treatment \[immunosuppressive treatment (IST)\] completely tapered for at least two weeks prior to study entry. Prednisone dose ≤ 5 mg/day or equivalent corticosteroid dose is allowed. * Participants who are found with MRD positivity while still on or tapering systemic GvHD prophylaxis or treatment, MRD positivity must be re-confirmed at least 2 week after the last dose of IST * For the adult cohorts, participants must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2. For the adolescent cohort, participants must have a Karnofsky (age ≥ 16 years) or Lansky (age \< 16 years) performance status score ≥ 50%. Exclusion Criteria: * Prior exposure to TIM-3 directed therapy at anytime. * History of severe hypersensitivity reactions to any ingredient of study drug(s) (azacitidine, sabatolimab) or monoclonal antibodies (mAbs) and/or their excipients * Active Hepatitis B (HBV) or Hepatitis C (HCV) infection. Participants whose disease is controlled under antiviral therapy should not be excluded. * Active acute GvHD grade III-IV according to standard criteria (Harris 2016). * Active moderate chronic GvHD of the lungs according to NIH consensus criteria. Active severe chronic GvHD according to NIH consensus criteria. * History of another primary malignancy that is currently clinically significant or currently requires active intervention. Participants who are receiving adjuvant therapy, such as hormone therapy, are eligible * Any concurrent severe and/or active uncontrolled infection requiring parenteral antibacterial, antiviral or antifungal therapy (such as severe pneumonia, meningitis, or septicemia) * Active autoimmune disease requiring systemic therapy (e.g. corticosteroids). Topical, inhaled, nasal and ophthalmic steroids are not prohibited. Replacement corticosteroids therapy is allowed and not considered a form of systemic treatment * Live vaccine administered within 30 days prior to the first day of study treatment (Cycle 1 Day 1) * Other concurrent severe and/or uncontrolled medical conditions (e.g. uncontrolled diabetes mellitus, chronic obstructive or chronic restrictive pulmonary disease including dyspnoea at rest from any cause) or history of serious organ dysfunction or disease involving the heart, kidney, or liver