Radioimmunotherapy with 131I-anti-CD45 prior to HCT in high-risk AML, ALL, or MDS
Orozco JJ, Vo PT, Gooley TA, et al. Targeted Radiation Delivery Before Haploidentical HCT for High-Risk Leukemia or MDS Patients Yields Long-Term Survivors. Clinical Cancer Research. 2023; (doi: 10.1158/1078-0432.CCR-23-1200).
Researchers say prolonged survival is possible in patients with high-risk leukemia or MDS who receive targeted radioimmunotherapy prior to haploidentical hematopoietic cell transplantation (HCT). They assembled a study population of 20 adults with relapsed/refractory acute myeloid leukemia (AML), 4 with acute lymphoid leukemia (ALL), and 1 with myelodysplastic syndrome (MDS). All participants in the Phase I/II trial underwent nonmyeloablative conditioning with fludarabine, cyclophosphamide, and 2 Gy total body irradiation before HCT. At the same time, they also all received an infusion of iodine-131 (131I)-anti-CD45 antibody BC8. The entire cohort achieved morphologic remission 28 days after the transplant procedure, including seven patients with prior, unsuccessful HCT. At 1-year followup, estimated overall survival (OS) was 40% and estimated progression-free survival (PFS) was 32%. Relapse and non-relapse mortality at that interval was measured, respectively, at 56% and 12%. At 2-year followup, OS and PFS were both at 24%. The study results suggest that 131I-anti-CD45 radioimmunotherapy ahead of haploidentical marrow HCT can benefit some patients without introducing further toxicity.