Prophylactic Donor Lymphocyte Infusion Safe, Efficacious for GVHD After Haplo-HCT in Children With Myeloid Neoplasms

Prophylactic donor lymphocyte infusion (pro-DLI) for prevention of graft vs host disease (GVHD) after haploidentical hematopoietic cell transplantation (haplo-HCT) with posttransplant cyclophosphamide (PTCy) is safe and efficacious in pediatric patients with high-risk myeloid neoplasms, according to research published in Pediatric Blood & Cancer.

Researchers conducted a retrospective observational study to evaluate the efficacy and safety of pro-DLI for GVHD prophylaxis after PTCy-based haplo-HCT in pediatric patients with high-risk myeloid neoplasms. Patients enrolled in the study underwent haplo-HCT with PTCy at a single children’s hospital between June 2018 and August 2022.

Study endpoints included neutrophil and platelet recovery, acute GVHD (aGVHD), and chronic GVHD (cGVHD), disease-free survival (DFS), GVHD-free relapse-free survival (GRFS), nonrelapse mortality (NRM), and overall survival (OS).

The cohort included 54 pediatric patients (56% male) with high-risk acute myeloid leukemia (n=46) and myelodysplastic syndromes (n=8). Patients had a median age of 5.6 years (range, 0.7-16.0 years). Most (88.9%) patients received allogeneic peripheral blood stem cell transplantation (PBSCT) from parents, while the rest received PBSCT from siblings (11.1%). The median follow-up duration was for 19.7 months (range, 3.4-46.6 months).

On day 100 after transplant, there was a cumulative incidence of 37.0% (95% CI, 22.7-48.7%) of grade II-IV aGVHD and 16.7% (95% CI, 6.1-26.0%) of grade III-IV aGVHD. The 2-year cumulative incidence of cGVHD was 19.9% (95% CI, 5.9-31.8%), and the 2-year rate of moderate/severe cGVHD was 8.1% (95% CI, 0-16.7%). No graft-failure events occurred.

The 2-year rates were 5.1% (95% CI, 0-11.7%) for NRM, 16.6% (95% CI, 5.3-26.6%) for relapse, 78.9% (95% CI, 68.0-91.6%) for DFS, 62.2% (95% CI, 49.4-78.3%) for GRFS, and 87.3% (95% CI, 78.3-97.4%) for OS.

“To the best of our knowledge, this is the first study showing the efficacy of pro-DLI in decreasing relapse and improving survival after PTCy-based haploidentical HSCT in pediatric [myeloid neoplasms],” the study authors wrote in their report. “This study demonstrates excellent engraftment and overall survival, with low rates of relapse and comparable rates of [GVHD].”

Limitations of the study included the retrospective design, relatively small sample size, narrow range of hematological disorders, nontraditional GVHD prophylaxis regimen of PTCy, and cryopreserved G-CSF-primed cells of pro-DLI.

Reference

Qi SS, Chen Z, Du Y, et al. Prophylactic donor lymphocyte infusion after haploidentical hematopoietic cell transplantation and post-transplant cyclophosphamide for treatment of high-risk myeloid neoplasms in children: A retrospective study. Pediatr Blood Cancer. Published online September 5, 2023. doi:10.1002/pbc.30659