High engraftment with new umbilical transplant technique
REPORTING FROM THE 2018 BMT TANDEM MEETINGS
Complete chimerism was achieved rapidly with the nonmyeloablative regimen as well, and CD4 recovery was brisk, as had been seen with myeloablative conditioning before MGTA-456 transplantation.
Compared with historical controls, “MGTA-456 retains the benefits of low chronic-graft-versus host disease and high survival despite higher disease risk and age” in the study group, Dr. Wagner said. There were no significant differences between the intervention and historical control arms of the nonmyeloablative study in acute or chronic GVHD, relapse, or overall survival.
The use of MGTA-456 occurs against the backdrop of a history of high survival rates with UCB transplantation – about 70% at 5 years, Dr. Wagner said. However, when conventional culture and expansion methods for UCB were used, the median time to engraftment had been reported to be 25 days with a 79% engraftment rate. This contrasts with the mean 13 days to engraftment for peripheral blood transplants and 18 days for bone marrow transplants. All of these transplant sources, regardless of whether the transplant was matched or mismatched, have engraftment rates of 92%-96%, said Dr. Wagner (Lancet Oncol. 2010; 11[7]:653-60).
When an AHR antagonist is used for UCB expansion, hematopoietic stem cell renewal is upped because cell differentiation is blocked, which means expansion is all driven toward hematopoietic stem cell self-renewal, Dr. Wagner said. Of the 36 available samples, MGTA-456 achieved a median 327-fold expansion of CD34+ cells, which enabled investigators to deliver a median CD34+ dose of 17.5 X 106 cells/kg.
