Fludarabine, Campath and Low dose Cyclophosphamide (FCClow) with or without TBI Conditioning Results in Excellent Transplant Outcomes in Children with Severe Aplastic Anemia

Abstract Various reduced-intensity conditioning regimens are in use for allogeneic hematopoietic cell transplant (HSCT) in idiopathic severe aplastic anemia (SAA). We describe the use of fludarabine, Campath and low dose cyclophosphamide (FCClow) conditioning in 15 children undergoing related or unrelated donor transplants. Total body irradiation (TBI) of 2Gy was added for unrelated donor HSCT. At a median follow-up of 2.3 years, the failure-free survival was 100%, with low rates of infection and toxicity. There was no occurrence of grade III-IV acute GvHD. All patients had full donor myeloid chimerism post-HSCT, even with mixed chimerism in the T cell lineage. The absence of chronic GvHD and long-term stable mixed donor T cell chimerism confirms immune tolerance following FCClow (±TBI) conditioned transplantation in children with SAA.