This is a multicenter, open-label study (NCT05223699). Adult participants (pts) are eligible who have a WHO-defined diagnosis of CD117+ R/R AML or MDS-EB...Preliminary data show in vivo stability of the ADC with rapid clearance from blood, robust binding of MGTA-117 on CD117+ cells, and early evidence of single-agent biological activity....The trial continues to advance, and progress is being made toward development of MGTA-117 as a myelodepletive conditioning agent for HSCT in AML/MDS and gene therapy indications.