Treosulfan-Based Conditioning in Allogeneic Stem Cell Transplantation for Myelofibrosis: A Systematic Review

Background: Allogeneic hematopoietic stem cell transplantation (allo-HCT) is the only curative therapy for myelofibrosis (MF), but its use is limited by substantial transplant related morbidity and mortality, particularly in older or comorbid patients. Treosulfan has emerged as a less toxic alternative to busulfan, with potential advantages in myeloablative and reduced intensity conditioning. Methods: We conducted a comprehensive, multi-database literature search (PubMed, Scopus/EMBASE, Cochrane Library, Web of Science, and grey literature) for studies published between 2000 and 2025 evaluating treosulfan-based conditioning in MF patients undergoing allo-HCT. Data on patient characteristics, conditioning regimens, engraftment, graft-versus-host disease (GVHD), and survival outcomes were synthesized. Results: Eight studies including more than 800 patients were analyzed. Treosulfan was most commonly combined with fludarabine, with or without additional agents. Engraftment rates were consistently high at 94 to 100%, with low non-relapse mortality (NRM) and favorable progression-free survival (PFS). An EBMT registry study demonstrated superior survival and significantly lower NRM compared with busulfan based regimens. Benefits were observed across older patients, alternative donors, and second transplants. Higher treosulfan doses were associated with increased toxicity in some cohorts. Conclusions: Treosulfan based conditioning offers an effective and better tolerated option for MF transplantation. Prospective trials are needed to refine dosing and patient selection.