Posted: Wednesday, August 10, 2022
An ongoing phase I/II trial, the details of which were presented at the American Society of Clinical Oncology (ASCO) 2022 Annual Meeting (Abstract TPS3156), will evaluate the safety and clinical efficacy of MGTA-117, a novel ant-CD117 antibody-drug conjugate, in the treatment of patients with AML or myelodysplasia with excess blasts. MGTA-117 is a potential conditioning agent for hematopoietic stem cell transplantation candidates; the study authors recognize the possibility that patients may undergo transplantation at least 29 days after receiving MGTA-117.
“Human hematopoietic stem cells and AML tumor cells express high levels of CD117, and MGTA-117 potently depletes these target cells, with [a half-maximal inhibitory concentration] of < 10 pM in vitro,” noted Andrew S. Artz, MD, of City of Hope, Duarte, California, and colleagues. “MGTA-117 has demonstrated in vitro and in vivo stability, confirming its characterization as a highly potent and selective agent.”
The multicenter dose-escalation study will enroll patients between the ages of 18 and 75 who have been diagnosed with CD117-positive relapsed/refractory AML or myelodysplasia with excess blasts and at least 5% marrow myeloblasts with an Eastern Cooperative Oncology Group performance status of up to 2. Patients will participate in a dose-escalation process to meet the study’s primary endpoint of determining the minimum safe and effective dose of MGTA-117. Efficacy will be measured by CD117 receptor occupancy in circulating leukemic blasts following dose administration.
A 21-day observation window for dose-limiting toxicities will be established. Reticulocyte, neutrophil, and platelet counts in peripheral blood will be monitored and measured against baseline counts from leukemic blasts or stem/progenitor cells in peripheral blood and/or bone marrow.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.