Bone marrow transplantation for non-malignant diseases using treosulfan-based conditioning

Area of Science:

• Pediatric Hematology
• Oncology
• Transplantation Immunology

Background:

• Treosulfan is an alkylating agent with low toxicity, increasingly used in pediatric hematopoietic stem cell transplantation (HSCT) for non-malignant diseases.
• Limited evidence exists comparing different treosulfan-based conditioning protocols.
• This study retrospectively analyzes data from three Israeli centers using varied treosulfan regimens.

Purpose of the Study:

• To compare the efficacy and safety of different treosulfan-based conditioning regimens in pediatric HSCT.
• To evaluate overall survival (OS) and disease-free survival (DFS) across treatment groups.
• To assess donor chimerism rates and identify factors influencing transplant success.

Main Methods:

• Retrospective data collection from 44 children undergoing 45 HSCTs.
• Patients received treosulfan combined with fludarabine/thiotepa (Flu/Treo/TT), fludarabine (Flu/Treo), or cyclophosphamide (Treo/Cy).
• Outcomes analyzed included OS, DFS, and donor chimerism.

Main Results:

• Overall survival was 70.5% and disease-free survival was 54.6%.
• No statistically significant differences in OS or DFS were observed between the conditioning regimens.
• Patients under one year old had higher OS (88.2%).
• The Flu/Treo/TT regimen resulted in significantly higher 100% donor chimerism (94.7%) compared to Flu/Treo (66.7%) and Treo/Cy (16.7%).

Conclusions:

• Treosulfan-based conditioning regimens demonstrate comparable survival outcomes in pediatric HSCT for non-malignant diseases.
• The combination of fludarabine, treosulfan, and thiotepa may enhance donor chimerism.
• Prospective studies are necessary to establish the optimal treosulfan preparative regimen for this patient population.