[BCMA/CS1 bispecific CAR-T cell therapy for multiple myeloma complicated with thrombocytopenia: a case report and literature review].

Abstract

Objective: To investigate the clinical manifestations, diagnostic and therapeutic strategies, for thrombocytopenia after BCMA/CS1 bispecific chimeric antigen receptor T-cell (CAR-T cell) therapy in patients with multiple myeloma. Methods: Retrospective collection and analysis were conducted on the clinical data of a patient with multiple myeloma who received BCMA/CS1 bispecific CAR-T cell therapy in the Hematology Department of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, in June 2021. To review the literature, Chinese databases (CNKI, Wanfang Database) and PubMed were searched from their inception up to November 2024 using the keywords "chimeric antigen receptor T-cell therapy", "thrombocytopenia", "CAR-T", "BCMA", and "CS1" . Results: A 72-year-old male patient was diagnosed with light chain κ-type multiple myeloma (R-ISS stage Ⅱ) in a local hospital and had a prolonged treatment course with poor disease control despite multiple adjustments of chemotherapy regimens. The patient met the inclusion criteria for the BCMA/CS1 dual-target CAR-T cell clinical trial (NCT04662099) and achieved complete remission two months after receiving a low dose of CAR-T cells. On the 8th day after CAR-T cell infusion, the patient developed grade 3 cytokine release syndrome, followed by severe gastrointestinal bleeding and persistent grade ≥3 thrombocytopenia, accompanied by a significant increase in thrombopoietin levels, with no megakaryocytes observed in bone marrow cytology. After treatment with rituximab, significant improvement was observed with platelet count gradually increased. However, the patient experienced persistent malnutrition and cachexia, and transferred to the gastroenterology department, after which follow-up was lost. A total of 24 relevant English articles and 8 Chinese articles were retrieved from the literature search. Conclusion: CAR-T cell therapy associated thrombocytopenia is characterized by thrombocytopenia and megakaryocyte production disorders. Persistent thrombocytopenia increases the risk of bleeding, and the use of CD20 monoclonal antibodies and supportive therapy can effectively improve thrombocytopenia.