Treosulfan-based conditioning strategies in older or frail patients undergoing allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) constitutes the only curative option for patients with hematological malignancies. Nevertheless, older or comorbid allo-HCT recipients are at greater risk for several allo-HCT-related complications. Treosulfan has emerged as an optimal part of prior HCT conditioning regimens in this patient population. We summarize the clinical outcomes of older/frail patients treated with treosulfan-based regimens and, based on the pharmacological properties of treosulfan and the data derived from clinical studies, and provide some insights regarding the rigorous clinical evaluation of patients in everyday clinical practice. Treosulfan is a safe and effective agent for conditioning in older or comorbid allo-HCT recipients, exhibiting comparable or superior survival outcomes compared to reduced intensity regimens and busulfan, with similar or lower rates of graft-versus-host disease and reduced non-relapse mortality. Before allo-HCT, geriatric assessment and evaluation of the underlying comorbidities are important for the selection of a personalized conditioning regimen.