Endocrine Late Effects Requiring Therapy Following Allogeneic Hematopoietic Cell Transplantation Using Treosulfan-Based Conditioning for Treatment of Non-Malignant Diseases

Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for many patients with non-malignant disease. Standard chemotherapy conditioning protocols are associated with undesirable late effects, but incidence of long-term endocrine effects following treosulfan-based conditioning regimens are unknown. To examine the cumulative incidence of endocrine late effects associated with treosulfan-based based conditioning in patients with non-malignant diseases. A retrospective, institutional analysis of patients with non-malignant diseases who underwent HCT with TREO (treosulfan, fludarabine, anti-thymocyte globulin ± thiotepa) conditioning regimens between 2006-2024 was performed. The cumulative incidences of the following endocrine late effects were analyzed: serum cholesterol >200 ± on medication, serum triglycerides >150 mg/dL, serum glucose >ULN and on therapy, bone mineral density Z-Score ≤-2.0 using dual X-ray absorptiometry, incidence of patients prescribed calcium/bisphosphonate/vitamin D, incidence of patients requiring growth hormone therapy, and overall reported # children fathered, pregnancies, and live births. A total of 88 survivors were included in this analysis. The median age at HCT was 4.4 (range 0.2-32.4) years for this HCT survivor group. Median follow-up post-HCT was 7.1 years (range 0.9-14.5) years for this survivor group. Endocrine late effects are uncommon in patients with non-malignant disease following HCT with treosulfan-based conditioning. Additional work is underway to describe additional organ system late effects and to compare these findings with a matched cohort of survivors who received other conditioning agents (e.g. busulfan).