High-dose treosulfan in conditioning prior to hematopoietic stem cell transplantation

Importance of the field: Despite the marked development in the field of preparative regimens prior to hematopoietic stem cell transplantation (HSCT) over the last decade, the search for a superior conditioning agent is still continuing. In view of the literature reports, treosulfan (TREO), a structural analog of busulfan (BU), appears to be a promising candidate in terms of myeloablative, immunosuppressive and antimalignancy effects as well as low organ toxicity. Areas covered in this review: The article focuses on pharmacological activity, pharmacokinetics and toxicity of TREO. Compressed description of the drug-based conditioning prior to HSCT is also presented. Finally, TREO and BU characteristics are compared. Specific information of TREO concerning pediatric and adult patients is provided throughout the whole paper. The data refer predominantly to the publications, in majority from the last 10 years. What the reader will gain: According to our best knowledge, the paper is the first such comprehensive review on TREO, especially in terms of its application in pediatric HSCT. Take home message: TREO offers a great potential as a conditioning agent prior to HSCT but further investigations of the drug are warranted to clearly verify its advantages. However, we expect TREO to be registered as a novel conditioning agent in the near future.