SNDX-5613 (5613) is a potent, selective protein-protein interaction inhibitor of menin being evaluated in the AUGMENT-101 study, a first-in-human (FIH), Ph 1/2 study in pts with R/R acute leukemia. Here, we report the results of the completed, Ph 1 component....The study includes 2 parallel dose-escalation cohorts: pts not taking (Arm A) or taking (Arm B) strong CYP3A4 inhibitors....The composite CR (CRc: CR+CRh+CRp+CRi/MLFS) rate was 44% (20/45 pts) (Table 3). Among pts with MLLr leukemia, the CRc rate was 49% (17/35 pts) and in pts with mNPM1 leukemia, the CRc rate was 30% (3/10 pts); 14/20 (70%) pts with CRc achieved MRD negativity assessed locally by flow cytometry or PCR....In this FIH Ph 1 study, SNDX-5613 demonstrates an acceptable safety profile and promising antileukemic activity in pts with heavily pretreated R/R MLLr and mNPM1 acute leukemia.