Patients who meet eligibility criteria will be randomly assigned to one of two treatment groups: 1) 33A plus HMA (Experimental Arm); or 2) placebo plus HMA (Comparator Arm). In addition to evaluating survival and remission rates, the minimal residual disease (MRD)-negative remission rate, duration of remission, event free- and leukemia-free survival, and safety and tolerability will be compared between arms.