Does Post-Transplantation Cyclophosphamide Inhibit Graft-versus-Leukemia?

Fludarabine and antithymocyte globulin-based conditioning regimen combined with post-transplantation cyclophosphamide for haploidentical allogeneic hematopoietic stem cell transplantation in patients with high-risk acute myeloid leukemia and myelodysplastic syndrome

INTRODUCTION

Relapse and graft-versus-host disease (GVHD) are the important complications influencing mortality for patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). GVHD prophylaxis based on post-transplant cyclophosphamide (PTCy) or antithymocyte globulin (ATG) is widely used in haploidentical HSCT (haplo-HSCT).

OBJECTIVE

We developed a modified intensified conditioning regimen including fludarabine (Flu) and investigated the effect of ATG-PTCy combination on transplant outcomes in high-risk AML and MDS compared with those patients who received only ATG as GVHD prophylaxis.

METHODS

A total of 80 patients with high-risk AML and MDS were divided into two groups and assigned to one-to-one pairing.

RESULTS

The modified ATG-PTCy group had more infused mononuclear cells, CD34-positive cells and CD3-positive cells than those in the ATG group (P < 0.05). The amount of platelet transfusion was higher in the ATG group than the modified ATG-PTCy group [2 (range, 1-6) U vs 2 (range, 1-5) U, P = 0.005]. The median of platelet recovery was better in the modified ATG-PTCy group than in the ATG group (12 days vs 13 days,P = 0.041). The infection rates of bacteria, fungi and virus at 100 days after transplantation were similar in both groups. Compared with the ATG group, individuals who received the modified ATG-PTCy regimen had higher 2-year GVHD- and relapse-free survival(GRFS) [60.0% (95%CI, 44.9-75.1%) vs 34.8% (95%CI, 19.9-49.7%), P = 0.028]; lower 180-day incidence of II-IV acute GVHD (aGVHD) [15.0% (95%CI, 4.0-26.0%) vs 39.8% (95%CI, 23.9-55.7%), P = 0.029]; lower 1-year incidence of moderate to severe chronic GVHD (cGVHD) [2.9% (95%CI, 2.0-3.8%) vs 19.6% (95%CI, 5.3-33.9%), P = 0.039]; and without an increase in the 2-year cumulative incidence of relapse (CIR) [19.5% (95%CI, 6.6-32.4%) vs 30.4% (95%CI, 15.3-45.5%), P = 0.291].

CONCLUSIONS

High-dose stem cells can promote blood cell implantation. The modified ATG-PTCy combination was associated with decreased risk of aGVHD and cGVHD, no increased risk of recurrence, and improved GRFS. It represents an effective strategy for high risk AML and MDS.

Possible prognostic impact of WT1 mRNA expression at day + 30 after haploidentical peripheral blood stem cell transplantation with posttransplant cyclophosphamide for patients with myeloid neoplasm: a multicenter study from the Okayama Hematological Study Group

BACKGROUND

Previous studies have revealed that relapse of myeloid neoplasms after allogeneic hematopoietic stem cell transplantation (allo-HSCT) could be predicted by monitoring Wilms' tumor 1 (WT1) mRNA expression. However, only a few studies have investigated patients who received human leukocyte antigen-haploidentical stem cell transplantation with posttransplant cyclophosphamide (PTCY-haplo). In this study, we investigated the relationship between WT1 mRNA levels and clinical outcomes in the PTCY-haplo group, and compared them with those in the conventional graft-versus-host disease prophylaxis group (conventional group).

METHODS

We retrospectively analyzed 130 patients who received their first allo-HSCT between April 2017 and December 2020, including 26 who received PTCY-haplo.

RESULTS

The WT1 mRNA expression level at day + 30 after allo-HSCT associated with increased risk of 1-year cumulative incidence of relapse (CIR) was ≥ 78 copies/μg RNA in the conventional group (p < 0.01) and ≥ 50 copies/μg RNA in the PTCY-haplo group (p = 0.03).

CONCLUSIONS

The appropriate cutoff level of WT1 mRNA at day + 30 after allo-HSCT for predicting prognosis in patients treated with PTCY-haplo may be < 50 copies/μg RNA.

Post-transplant cyclophosphamide in one-antigen mismatched unrelated donor transplantation versus haploidentical transplantation in acute myeloid leukemia: a study from the Acute Leukemia Working Party of the EBMT

Whether to choose Haploidentical (Haplo) or one-antigen mismatched unrelated donor (1Ag-MMUD) hematopoietic cell transplantation (HCT) with post-transplant cyclophosphamide (PTCy) remains an unanswered question. We compared PTCy- Haplo-HCT to PTCy-1Ag-MMUD-HCT for acute myeloid leukemia (AML) in complete remission (three groups: 1Ag-MMUD using peripheral blood (1Ag-MMUD-PB; n = 155); Haplo using bone marrow (Haplo-BM; n = 647) or peripheral blood (Haplo-PB; n = 949)). Haplo-BM and Haplo-PB had a higher non-relapse mortality (NRM) compared to 1Ag-MMUD-PB (HR 2.28, 95% CI 1.23-4.24, p < 0.01; HR 2.65, 95% CI 1.46-4.81, p < 0.01, respectively). Haplo groups experienced a lower leukemia-free survival (LFS) compared to 1Ag-MMUD-PB (Haplo-BM: HR 1.51, 95% CI 1.06-2.14, p = 0.02; Haplo-PB: 1.47, 95% CI 1.05-2.05, p = 0.02); overall survival (OS) was also lower in Haplo-HCT (Haplo-BM: HR 1.50, 95% CI 1.02-2.21, p = 0.04; Haplo-PB: HR 1.51, 95% CI 1.05-2.19, p = 0.03). No differences were observed for graft-versus-host/relapse-free survival (GRFS) and relapse incidence (RI). Haplo-BM was associated with a lower risk of grade III-IV acute graft-versus-host disease (GVHD) (HR 0.44, 95% CI 0.24-0.81; p < 0.01), while no statistical differences were observed between groups for grade II-IV aGVHD and for cGVHD. Use of PTCy in 1Ag-MMUD-HCT is a valid alternative to consider when using alternative donors. Larger analysis of 1Ag-MMUD versus Haplo-HCT are warranted.

HLA-Haploidentical Family Donors: The New Promise for Childhood Acute Lymphoblastic Leukaemia?

Allogeneic haematopoietic stem cell transplantation (HSCT) is indicated in children with high-risk, relapsed or refractory acute lymphoblastic leukaemia (ALL). HLA-matched grafts from cord blood and stem cell repositories have allowed patients without suitable sibling donors to undergo HSCT. However, challenges in procuring matched unrelated donor (MUD) grafts due to high cost, ethnic disparity and time constraints have led to the exponential rise in the use of stem cells from human leukocyte antigen (HLA)-haploidentical family donors. Whilst HLA-haploidentical HSCT (hHSCT) performed in adult patients with acute leukaemia has produced outcomes similar to MUD transplants, experience in children is limited. Over the last 5 years, more data have emerged on hHSCT in the childhood ALL setting, allowing comparisons with matched donor transplants. The feasibility of hHSCT using adult family donors in childhood ALL may also address the ethical issues related to selection of minor siblings in matched sibling donor transplants. Here, we review hHSCT in paediatric recipients with ALL and highlight the emergence of hHSCT as a promising therapeutic option for patients lacking a suitable matched donor. Recent issues related to conditioning regimens, donor selection and graft-vs.-host disease prophylaxis are discussed. We also identify areas for future research to address transplant-related complications and improve post-transplant disease-free survival.