Conditioning regimen for hematopoietic cell transplant in transfusion dependent thalassemia: Recommendations from the EBMT practice harmonisation and guidelines committee.

Allogeneic hematopoietic cell transplantation (HCT) has represented a curative therapy for transfusion-dependent thalassemia (TDT) for over four decades. Despite major advances in conditioning regimens, graft-versus-host disease (GVHD) prophylaxis, and supportive care, substantial heterogeneity persists in patient preparation strategies and transplant protocols across centers. To address these practice variations and provide harmonized guidance, the European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonization and Guidelines Committee convened an international expert workshop in Berlin (Germany) on September 29-30, 2025. A structured literature review was conducted in advance. Evidence was presented, critically appraised, and discussed in consensus-based sessions. Recommendations were formulated using the GRADE framework and approved by panel members and external reviewers. These guidelines summarize contemporary evidence regarding pre-transplant optimization, conditioning regimens according to age and donor type, management of iron overload and ineffective erythropoiesis, and approaches for alternative donor transplantation and gene therapy. The aim of this document is to provide practical, evidence-informed recommendations to standardize HCT practice and optimize outcomes for children and adults with TDT globally, including in resource-limited settings.