St. Mary’s Hospital’s Catholic Hematology Hospital said Monday its haploidentical transplants (Haplo-HSCT) from half-matched sibling donors using a reduced-intensity regimen has shown positive outcomes compared to transplants from matched donors for acute myeloid leukemia patients.

The research team assigned 55 acute myeloid leukemia patients with half-matched human leukocyte antigens (HLA) and another 55 patients with HLA-matched unrelated donors.

Researchers compared the five-year survival rate measured from 2013 to 2018. They found that acute myeloid leukemia patients who received haploidentical transplants, a transplant with half-matched siblings, or HLA-matched unrelated donors to show 65 and 54 percent survival rates, respectively.

Professors Kim Hee-je and Cho Byoung-sik led the study.

They said the study results imply that haploidentical transplants showed an equivalent therapeutic effect to transplantation from an unrelated donor.

The research team saw no transplant rejection in the Haplo-HSCT group using anti-thymocyte globulin, confirming the superiority of the reduced-intensity regimen differentiated from the methods based on post-transplant cyclophosphamide (PT-Cy) used in the U.S. and Europe.

With the recent development of transplantation techniques, health providers have partially broken through the genetic mismatch problems between familial donors, allowing hematopoietic stem cell transplants even with half-matched related donors, according to the hospital.

Besides, the transplant method has shortened the time needed for finding and preparing a donor, which took about six weeks on average, it said.

“The study could work as the base for supporting in situations where domestic acute myeloid leukemia patients require urgent transplantation, uses as a preemptive intervention for those with a high risk of relapse, and treat patients subject to donor-derived natural killer cells or antigen-specific T-cells therapies,” Professor Cho said.

Professor Kim said, “The stable transplantation protocol with the half-matched familial donor will be used as a basic platform for various donor-derived immune cell therapies that are being actively studied in patients with recurrent, refractory, or high-risk patients, and will maximize treatment outcomes.”

The study results were published in the latest issue of the American Journal of Hematology.