Conditioning Regimen in Elderly AML Patients Receiving Haplo-HSCT.

Bu/Cy/Flu/ATG Versus Bu/Cy/ATG Conditioning Regimen in Elderly AML Patients Receiving Haploidentical Hematopoietic Stem Cell Transplantation: a Prospective, Randomized, Controlled Study

Elderly AML patients receiving conventional chemotherapy have poor prognosis. Allo-HSCT offers better long-term survival than chemotherapy, while high TRM limits its use. Current research focuses more on improving conditioning regimens to reduce TRM. Studies suggest Bu/Flu/Cy/ATG are safer and more effective for elderly AML haplo-HSCT, lowering TRM. However, prospective randomized trials are lacking. This study aims to compare Bu/Flu/Cy/ATG vs. Bu/Cy/ATG to determine if TRM can be reduced in elderly AML undergoing haplo-HSCT.

The prognosis of elderly patients with acute myeloid leukemia (AML) undergoing conventional chemotherapy is poor. Compared with chemotherapy, allogeneic hematopoietic stem cell transplantation (allo-HSCT) can improve long-term survival in elderly patients. However, the high transplantion-related mortality (TRM) limited its application. Currently, the top priority in transplantation for elderly AML patients is to reduce TRM through methods such as optimizing conditioning regimens, reducing graft-versus-host disease (GVHD), and preventing infections. Present research primarily focuses on optimizing conditioning regimens. Both domestic and international studies, as well as our team's preliminary research, suggest that replacing cyclophosphamide (Cy) with fludarabine (Flu) can reduce toxicity. Earlier prospective single-arm clinical study in our team confirmed that the Bu/Flu/Cy/ATG regimen is a safe and effective conditioning protocol for haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in elderly AML patients. This study aims to use a prospective randomized controlled trial to verify whether the Bu/Flu/Cy/ATG conditioning regimen can reduce TRM compared with the Bu/Cy/ATG regimen in elderly AML patients undergoing haplo-HSCT.

Inclusion Criteria:

- (a)Diagnosed with AML in first complete remission (CR1). (b)Age ≥55 years. (c)Availability of an haploidentical donor, first transplant, no matched sibling or unrelated donor.

(d)Willingness to provide written informed consent.

Exclusion Criteria:

• (a) Uncontrolled active infection. (b) Secondary AML. (c)Refusal to provide informed consent.