Abstract: Objective To analyze the clinical characteristics of patients with relapsed/refractory multiple myeloma (RRMM) after CAR⁃T cell therapy, and to explore the possible effective strategies for such patients in the future. Methods Patients with RRMM who were hospitalized in Beijing Chao⁃Yang Hospital, Capital Medical University from January 2020 to June 2024 were selected as the study subjects, and clinical characteristics and survival and survival after CAR⁃T cell therapy were analyzed. Results A total of 14 eligible RRMM patients who collected by the medical record system received CAR⁃T cell therapy targeting BCMA, with the median progression⁃free survival (PFS) of 17 months (range: 3-47 months）. At the time of disease recurrence and progression, 1 patient had extramedullary relapse, 2 patients developed secondary plasma cell leukemia,and 11 patients were intramedullay recurrence. Cytogenetics was examined in 7 patients, of which 4 patients with 1 high⁃risk gene, 1 patient with two high⁃risk genes. In the first salvage regimens, the commonly used agents included Daratumumab (6 cases）, Pomalidomide (5 cases）, and Carfilzomib (3 cases), and 3 patients were enrolled in the clinical trials. Among the 13 evaluable  patients, the overall response rate was 61.5% (8/13）, with a complete response rate of 30.8% (4/13) and a very good partial response rate of 23.1% (3/13）. The median follow⁃up time was 15 months (range: 1-32 months）, and the median PFS was 7 months. As of the last follow⁃up, 6 patients died. The median overall survival was 32 months. 1 patient developed a secondary malignance (lung cancer）. Conclusions Patients with RRMM receiving CAR⁃T cell therapy have a poor response to the currently available agents at the time of relapse and progression. 

Key words: Multiple myeloma, CAR-T cell therapy, Relapsed, Refractory, Salvage therapy, Prognosis