[Advances in the treatment of relapsed or refractory acute lymphoblastic leukemia]

Relapsed or refractory acute lymphoblastic leukemia remains associated with poor outcomes, with conventional chemotherapy offering limited long-term survival. In recent years, the introduction of immunotherapies, including antibody-based agents and chimeric antigen receptor T-cell (CAR-T) therapy, has improved treatment outcomes; however, optimization of therapeutic strategies remains a critical challenge. The anti-CD22 antibody-drug conjugate inotuzumab ozogamicin achieves high remission and minimal residual disease negativity rates, although it requires careful monitoring due to serious adverse events such as sinusoidal obstruction syndrome. The bispecific T-cell engager blinatumomab induces deep remission through T-cell-mediated cytotoxicity but is associated with cytokine release syndrome and neurotoxicity. These immunotherapies play a crucial role as a bridge to allogeneic hematopoietic stem cell transplantation, and timely transition to transplantation is essential for improving prognosis. CAR-T therapy has demonstrated high response rates and durable remissions; however, its use is limited by eligibility and access. Further optimization of frontline therapy, as well as development and appropriate integration of novel therapeutic approaches, is warranted.