Allogeneic Transplantation for Older Adults.

Allogeneic hematopoietic stem cell transplant (HCT) is a potentially curative treatment for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)-diseases that disproportionately affect older adults. Yet historically, older adults were excluded from HCT given its high morbidity and mortality and their increased susceptibility to these outcomes. This created a vast disparity: Those most often affected by AML and MDS were not considered eligible for its cure. Fortunately, clinicians have increasingly recognized that geriatric, functional, and frailty assessments, rather than chronological age alone, may help to identify older adults who are "fit" for HCT. This change in practice accompanied by the advent of azacitidine/venetoclax, which induces disease remission in a greater number of older adults, has led to the implementation of HCT in a wider population of patients than ever before. Moreover, improvements to HCT platforms, including reduced-intensity conditioning (RIC), post-transplantation cyclophosphamide (PTCy), abatacept, and the increasing use of unrelated and HLA-mismatched donors, have all contributed to the increased adoption and safety of HCT in adults up to 75 years old. In fact, select centers have extended the age of HCT eligibility up to the eighth decade. Herein, we review the data regarding the safety of existing platforms, the unique challenges inherent to HCT in older adults, and the efforts to optimize outcomes. Ultimately, in the modern era of HCT, age may, in fact, just be a number.