Comparative Study of BFC and BuCy Conditioning Regimen for Allo-PBSCT in Acute B-cell ALL

Overview

Comparing the efficacy and safety of fludarabine-containing BFC conditioning regimen with traditional BuCy conditioning regimen in Acute B-cell lymphoblastic leukemia patients who treated with allogeneic hematopoietic stem cell transplantation, to establish a conditioning regimen for improving the survival rate of patients with B-cell ALL after transplantation. Acute B-cell lymphoblastic leukemia (B-ALL) is a hematologic malignancy . The incidence of B-All is higher in children than in adults, but more than 80% of children patients can be cured by chemotherapy, while the survival rate of adult patients is less than 40%. Recurrence or progression of the disease is the main reason affecting the survival of patients. Although CD19-targeted CAR T cell therapy is an effective salvage treatment for relapsed and refractory B-ALL, bridging allogeneic hematopoietic stem cell transplantation is required after remission. 1-year LFS and 1-year OS were 11.6% and 32% in patients without bridging grafts after CAR T. Allogeneic hematopoietic stem cell transplantation is an effective treatment for ALL. Before the transplant, patients receive high doses of chemotherapy plus or total body irradiation（TBI） to 'creation of space' ，immunosuppression and disease eradication. This is called conditioning regimen. Conditioning regimen plays a key role in reducing tumor load and diseaseconditioning regimen recurrence. Conditioning regimen for different diseases are different. Conditioning regimen are based on TBI and chemotherapy BuCy, with low TBI recurrence rate but high treatment-related mortality (TRM). BuCY chemotherapy had low TRM but high recurrence rate, so there was no difference in total OS. Therefore, it is of great clinical value to explore a conditioning regimenprogram. How to optimize the preconditioning program before transplantation, so as to reduce the recurrence rate and prolong the survival period of adult B-cell ALL patients after transplantation has become a issue that needs to be solved urgently in clinical practice. BFC (Malilane + fludarabine + cyclophosphamide) is the addition of fludarabine to BuCy (malilane + cyclophosphamide). The combination of fludarabine and cyclophosphamide has synergistic effect, which can better kill B lymphocyte, and can enhance the killing effect of pretreatment regimen on B lymphocyte tumor.

This study was a prospective, randomized, controlled, single-center clinical study. A total of 142 patients eligible for the inclusion of acute B lymphoblastic leukemia were randomly divided into two groups: the experimental group (n = 71) and the control group (n = 71). The treatment group was given BFC conditioning regimen (fludalabine, marylan, cyclophosphamide), and the control group was given BuCY conditioning regimen (marylan, cyclophosphamide), and the patients were followed up to 1 year after transplantation. The 1-year disease-free survival rate of patients in the two groups was compared to evaluate whether increasing fludarabine could reduce the recurrence rate of patients after transplantation and thus improve the overall survival rate.