Successful BCMA CAR-T Therapy for Multiple Myeloma With Central Nervous System Involvement Manifesting as Cauda Equina Syndrome—A Wandering Road to Remission

Multiple myeloma (MM) with central nervous system (CNS) involvement is rare with only 1% occurrence. So far, there is no standard and effective treatment for CNS MM, and the predicted survival time is fewer than 6 months. Here, we reported a case of MM with CNS involvement presented with cauda equina syndrome (CES) who achieved complete remission after anti-BCMA chimeric antigen receptor T (CAR-T) cell therapy (Chictr.org.cn, ChiCTR1800017404). The expansion of BCMA CAR-T cells was observed in both peripheral blood (PB) and CSF. The CAR-T cells peaked at 2.4×106/L in CSF at day 8 and 4.1×109/L in PB at day 13. The peak value of IL-6 in CSF was obtained 3 days earlier, and it was almost 5 times higher than in the PB. Next, the morphological analysis displayed that the nucleated cells were eliminated from 300 nucleated cells/μL in CSF after CAR-T cell treatment one month and the patient achieved functional recovery with regressed lesion in PET-CT. The case demonstrated that BCMA CAR-T cells are effective and safe in multiple myeloma with central nervous system involvement patient.