A case of successful CAR-T cell therapy for early isolated CNS recurrence of DLBCL with persistent CAR-T cells.

Secondary central nervous system (CNS) lymphomas typically require CNS-penetrating drugs; however, the available agents are limited with temporary effects and poor outcomes. Chimeric antigen receptor T (CAR-T) cell therapy (lisocabtagene maraleucel; liso-cel) has been used to treat a few cases of isolated secondary CNS lymphoma. Herein, we report the case of a 66-year-old male diagnosed with diffuse large B-cell lymphoma (Ann Arbor grade IV; R-IPI, good risk; CNS IPI: Intermediate risk) who achieved complete remission (CR) after six courses of R-CHOP therapy. Three months later, he presented with ptosis and eye movement disorder. Systemic CT and bone marrow examination revealed no lymphoma. Although cranial-enhanced MRI showed normal findings, an increased number of B-cells (51/μL) with the original lymphoma phenotype (CD19+CD79a+CD5-CD10-CD20-Igλ+) was detected in cerebrospinal fluid (CSF), indicating an isolated CNS relapse. Seven high-dose methotrexate courses led to partial response. Subsequently, the patient received CAR-T cell therapy with tolerable adverse events - cytokine release syndrome treated with tocilizumab, no immune effector cell-associated neurotoxicity syndrome, and bone marrow failure treated with granulocyte-colony stimulating factor and eltrombopag. Sequential flow cytometry revealed a high peak of CAR-T cells and the presence of residual CAR-T cells in the peripheral blood, indicating immune surveillance of CNS lymphoma by CAR-T cells. This treatment led to a second CR. This case is the first to validate the efficacy and safety of CAR-T cell therapy for isolated secondary CNS lymphoma in clinical practice. Future accumulation of evidence on the efficacy and safety of CAR-T cell therapy is essential.