Adoptive Immunotherapy via Donor Lymphocyte Infusions following Allogeneic Hematopoietic Stem Cell Transplantation for Myelofibrosis: A Real-World, Retrospective Multicenter Study

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the sole curative option for myelofibrosis (MF). Relapse remains a significant problem, however, occurring in up to 20% to 30% of cases. Donor lymphocyte infusion (DLI) represents a potentially effective strategy for relapse prevention and management, but the optimal timing based on measurable residual disease/chimerism analyses and the choice of regimen remain undetermined. We performed a retrospective real-world analysis of a multicenter cohort of MF allo-HCT recipients from 8 European transplantation centers who received DLI between 2005 and 2022. Response was assessed using International Working Group-Myeloproliferative Neoplasms Research and Treatment-defined response criteria, and survival endpoints were estimated using the Kaplan-Meier estimator and log-rank test. The study included 28 patients with a median age of 58 years and a Karnofsky Performance Status of >80. The majority of patients had Dynamic International Prognostic Scoring System-plus intermediate-2 or high-risk disease at the time of allo-HCT. In vivo T cell depletion was used in 20 patients (71.2%), with 19 of the 20 receiving antithymocyte globulin. The indication for DLI was either preemptive (n = 15), due to a decrease in recipient chimerism (n = 13) or molecular relapse (n = 2), or therapeutic (n = 13) for clinician-defined hematologic/clinical relapse. No patient received DLI prophylactically. The median time of DLI administration was 23.4 months post allo-HCT. Of the 16 patients receiving multiple DLIs, 12 were part of a planned escalating dose regimen. The median follow-up from the time of first DLI was 55.4 months. The responses to DLI were complete response in 9 patients, partial response in 1 patient, and clinical improvement in 6 patients. Chimerism levels improved in 16 patients, and stable disease was reported in 5 patients. No response or progression was reported in 7 patients. DLI-induced acute graft-versus-host disease (aGVHD) was reported in 11 patients (39%), with grade III-IV aGVHD in 7 (25%). The median overall survival from the time of first DLI was 62.6 months, and the cumulative incidence of relapse/progression after first DLI was 30.8% at 6 months. This study highlights that good response rates can be achieved with DLI even after frank relapse in some patients in a cohort in which other treatment options are very limited. More prospective studies are warranted to identify the optimal DLI regimen and timing to improve patient outcomes.(c) 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Automated summary

The study retrospectively analyzed the real-world effectiveness of DLI in MF allo-HCT patients, and the results showed that DLI can achieve good responses even after relapse. However, acute graft-versus-host disease induced by DLI is a common side effect. More research is needed to determine the optimal DLI regimen and timing.