Patient flow diagram. ∗These patients started treatment after the 64th adult efficacy-evaluable patient and thus did not have the opportunity for ≥6 months of follow-up. †Mutational status was reviewed locally for eligibility in phase 2 and centrally confirmed for inclusion in the efficacy-evaluable population. ‡Twenty-one patients in the adult efficacy-evaluable population experienced treatment-emergent AEs that led to study drug discontinuation (patients may have experienced >1 treatment-emergent AE leading to discontinuation): sepsis (n = 5); septic shock (n = 2); acute respiratory failure, agitation, cardiac arrest, cardiorespiratory arrest, cerebral hemorrhage, death, febrile neutropenia, intracranial hemorrhage, osteomyelitis, posterior reversible encephalopathy syndrome, QTcF prolongation, stress cardiomyopathy, sudden death, syncope, and upper gastrointestinal hemorrhage (each n = 1). §Other reasons for discontinuation included patient moved to hospice (n = 2) and patient wished to discontinue due to worry over AEs (n = 1). ‖Five patients proceeded to HSCT while in remission during the study, including 1 patient who was taken off study due to AE but subsequently proceeded to HSCT 6 weeks later while still in remission without any intervening antileukemia therapy. PD, progressive disease; PR, partial remission.