Treosulfan-based conditioning has gained popularity in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) because of its presumed favourable efficacy and toxicity profile.... Show moreTreosulfan-based conditioning has gained popularity in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) because of its presumed favourable efficacy and toxicity profile. Treosulfan is used in standardized dosing regimens based on body surface area. The relationship between systemic treosulfan exposure, early and long term clinical outcome in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) for non-malignant diseases is unresolved. In this thesis we aimed to answer these questions. We found a relationship between the level of exposure to treosulfan and acute toxicity, but we found no relationship with the risk of rejection, survival and long-term endocrine complications. A personalized dose of treosulfan can therefore be useful to reduce toxicity in children, but because the toxicity profile of treosulfan is generally relatively mild, it will not be necessary in most cases. This is beneficial, because measuring blood levels is not always available in every hospital. Future research should focus on specific disease categories or patient groups that may benefit from treosulfan monitoring. More research is also needed on the late complications of treosulfan, such as dental, neurocognitive, hair, eye and lung problems, as this aspect becomes increasingly important as more (very young) patients undergo stem cell transplantation. Show less
