Treatment of CD19-Positive Mixed Phenotype Acute Leukemia with Blinatumomab

Mixed phenotype acute leukemia (MPAL) encompasses a rare group of acute leukemia with blasts expressing markers specific to several lineages, which accounts for 2-5% of all newly diagnosed cases of acute leukemia. At present, patients with MPAL are treated with acute lymphoblastic leukemia (ALL)-directed chemotherapy. However, the prognosis of MPAL, especially in cases of relapsed/refractory (R/R) disease, remains poor. Blinatumomab, a bispecific T cell-engaging antibody, has shown encouraging outcomes in R/R B cell ALL positive for CD19. Here, we report a patient with CD19+ MPAL who achieved complete remission after treatment with blinatumomab, which may be a therapeutic option for patients with relapsed CD19+ MPAL. To our knowledge, this is the first case report of MPAL treated with blinatumomab in Korea.