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Haploidentical versus matched unrelated donor transplants using post-transplant cyclophosphamide for lymphomas
Mussetti, A., Kanate, A. S., Wang, T., He, M., Hamadani, M., Sr, H. F., Boumendil, A., Sr., Glass, B., Castagna, L., Dominietto, A., et al
Transplantation and cellular therapy. 2022
Abstract
BACKGROUND when using post-transplant cyclophosphamide (PTCy) graft-versus-host-disease (GVHD) prophylaxis for lymphoma patients, it is currently unknown whether a matched unrelated donor (MUD) or a haploidentical related donor is preferable if both are available. OBJECTIVE In this study we wanted to test if using a haploidentical donor has the same results of a MUD. STUDY DESIGN a total of 2140 adults (34% CIBMTR, 66% EBMT registry) aged ≥18 years who received their first haploidentical hematopoietic cell transplant (haplo-HCT) or MUD-HCT (8/8 match at HLA-loci A, B, C, and DRB1) for lymphoma using PTCy-based GVHD prophylaxis from 2010-2019 were retrospectively analyzed. RESULTS The majority of both MUD and haploidentical HCTs received reduced intensity/non-myeloablative conditioning (74% and 77%, respectively), used a peripheral blood stem cell graft (91% and 60%, respectively) and a three-drug GVHD prophylaxis (PTCy + calcineurin inhibitor + MMF in 54% and 90%, respectively). Haploidentical HCT has less favorable results versus MUD cohort in terms of overall mortality (HR=1.69, 95%CI=1.30-2.27, p<0.001), progression-free survival (HR=1.39, 95%CI=1.10 - 1.79, p=0.008), non-relapse mortality (HR=1.93, 95% CI=1.21 - 3.07, p=0.006), platelets engraftment (HR=0.69, 95%CI=0.59 - 0.80, p<0.001), acute grade 2-4 GVHD incidence (HR=1.65, 95%CI=1.28 - 2.14, p<0.001) and chronic GVHD (HR=1.79, 95%CI=1.30 - 2.48, p<0.001). No significant differences were observed in terms of relapse and neutrophil engraftment. Adjusting for propensity score yielded similar results. CONCLUSION whenever MUD is available in a timely manner, it should be preferred over a haploidentical donor when using PTCy-based GVHD prophylaxis for patients with lymphoma.