Management of relapsed acute lymphoblastic leukemia in a patient with down syndrome: A case report.

Children with Down syndrome (DS) have a 10-20-fold increased risk of acute lymphoblastic leukemia (ALL) and heightened chemotherapy toxicity. Blinatumomab, a bispecific CD19 × CD3 T-cell engager, offers targeted immunotherapy with reduced myelotoxicity. We describe a 9-year-old girl with DS diagnosed with B-cell precursor ALL in early 2021 who relapsed during maintenance in September 2023. After reinduction, she received two 28-day blinatumomab cycles: the first resulted in <5 % blasts and undetectable minimal residual disease (MRD), and the second was well tolerated. She remains in remission pending allogeneic hematopoietic stem cell transplantation, highlighting blinatumomab's efficacy and safety as a bridge to transplantation.