Favorable response of a patient with primary B/myeloid mixed phenotype acute Leukemia to CD19-CAR-T: Case report and literature review

Abstract

Rationale: Mixed phenotype acute leukemia (MPAL) is a rare and heterogeneous type of leukemia known for its poor prognosis. The optimal treatment strategy for this condition currently lacks consensus, leaving uncertainty in its management. Nonetheless, a potential therapeutic option for patients with refractory MPAL who express target antigens is donor-derived chimeric antigen receptor T (CAR-T) cell therapy. Patient concerns: We recently reported a 61-year-old woman with MPAL and elucidated its diagnosis and treatment. Diagnosis: The diagnosis of MPAL was established based on the classification of World Health Organization in 2016. Interventions: Despite undergoing 3 different acute lymphoblastic leukemia (ALL) regimens and 1 acute myelogenous leukemia (AML) regimen, the patient did not achieve remission. Subsequently, the patient received human CD19-targeted CAR-T cell therapy. Outcomes: The patient achieved a successful and complete remission after CAR-T cell therapy. Tragically, 8 months after CAR-T infusion, the patient experienced a relapse characterized by CD19-negative disease and ultimately passed away. Lessons: This case underscores the potential efficacy and safety of human-derived CD19 CAR-T cell therapy in treating refractory MPAL. While this particular patient outcome was unfortunate, it suggests that CAR-T cell therapy may still hold promise as a viable treatment option for MPAL patients unresponsive to other therapies. Further research in this field is warranted to determine the most effective treatment strategies for managing this challenging disease.