alemtuzumab + busulfan + fludarabine

Alemtuzumab + busulfan + fludarabine is a reduced-toxicity conditioning regimen used before allogeneic hematopoietic stem cell transplantation (HSCT). This combination therapy helps decrease transplantation-related toxicity while improving engraftment rates. The regimen typically consists of targeted intravenous busulfan, fludarabine administered over several days, and alemtuzumab (a monoclonal antibody targeting CD52). This conditioning approach has shown efficacy in patients with various malignant and nonmalignant diseases, including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and hemophagocytic lymphohistiocytosis (HLH). The regimen allows for consistent engraftment with reduced rates of graft-versus-host disease (GVHD).