Inclusion Criteria:

          -  be willing and able to provide written informed consent for the trial

          -  be ≥ 60 years of age on day of signing informed consent

          -  have a newly diagnosed AML based on the World Health Organization (WHO) criteria,
             currently in first complete remission (CR) on a bone marrow biopsy performed within 4
             weeks of treatment initiation

          -  have received the last dose of induction or consolidation chemotherapy within 3 months
             of treatment initiation

          -  not be eligible for or willing to proceed with allogeneic stem cell transplant or for
             whom allogeneic stem cell transplant is not considered standard of care

          -  have a performance status of ≤ 1 on the Eastern Cooperative Oncology Group (ECOG)
             Performance Scale

          -  demonstrate adequate organ function, with all screening labs performed within 10 days
             of treatment initiation

          -  transfusion independent (no red blood cell or platelet transfusions in the preceding 2
             weeks of screening)

          -  negative urine and/or serum pregnancy test

          -  subjects of reproductive potential must agree to use acceptable birth control method

        Exclusion Criteria:

          -  have a diagnosis of Acute Promyelocytic Leukemia (APL) as defined by the WHO

          -  currently participating in or has participated in a study of an investigational agent
             or device within 4 weeks of treatment initiation

          -  have a diagnosis of immunodeficiency or are receiving systemic steroid therapy or any
             other form of immunosuppressive therapy within 7 days prior to treatment initiation

          -  have prior monoclonal antibody within 4 weeks prior to study Day 1 or have not
             recovered from adverse events due to agents administered more than 4 weeks earlier

          -  have prior chemotherapy, targeted small molecule therapy, or radiation therapy within
             2 weeks prior to study Day 1 have not recovered from adverse events due to previously
             administered agent(s)

          -  have a known additional malignancy that is progressing or requires active treatment
             except for basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or
             in situ cervical cancer that has undergone potentially curative therapy

          -  have known active central nervous system (CNS) involvement

          -  have an active autoimmune disease requiring systemic treatment within the past 3
             months

          -  has a history of (non-infectious) pneumonitis that required steroids or current
             pneumonitis

          -  have an uncontrolled, life-threatening active infection

          -  have a history or current evidence of condition, therapy, or laboratory abnormality
             that would preclude study participation in the opinion of the treating investigator

          -  have known psychiatric or substance abuse disorders that would interfere with
             cooperation with the trial requirements

          -  is pregnant or breastfeeding, or expecting to conceive or father children within the
             projected duration of the trial

          -  have received prior therapy with any antibody targeting the T-cell co-stimulation or
             checkpoint pathways

          -  have a known history of HIV

          -  have known active Hepatitis B or Hepatitis C

          -  have received a live vaccine within 30 days prior to treatment initiation