Outcome in Patients with Multiple Myeloma Receiving Salvage Therapy after Exposure to BCMA-Targeted CAR-T Therapy

Novel immunotherapies such as B-cell maturation antigen (BCMA) targeted directed chimeric antigen receptor T-cell (CAR T) therapy has shown favorable responses in patients with relapsed/refractory multiple myeloma (R/RMM). Despite their remarkable efficacy, disease progression still occurs in some patients with limited treatment options.

To investigate optimal strategies of subsequent therapies. We retrospectively performed a comprehensive analysis of the clinical characteristics, post-CAR T treatments, and outcomes of 31 patients from our center who experienced disease progression following BCMA-directed CAR T cell therapy.

A total of 48 patients with R/RMM were treated with BCMA-directed CAR-T in our study. 31 patients suffered progressive disease (PD) with 5 (range 2~9) prior lines of therapy and received subsequent salvage therapies, including one patient who lacked of following treatment details after relapse post BCMA-directed CAR T therapy but had available survival data. There was a median time of 41.5 months (7.7- 175.8 months) between the time of MM diagnosis and CAR-T infusion.

The median overall survival from relapse after BCMA CAR-T for the cohort of 31 patients was 19.5 months (95% confidence interval [CI], 15.7-NE months). Among them, 13 (42%) patients suffered death, although receiving antimyeloma treatment after PD. The overall response rate (ORR) and the median progression-free survival (PFS) for first line salvage therapy after BCMA CAR-T relapse was 46.7% and 5.5 months (95% CI 3.9-27.5 months). Carfilzomib-containing therapy is the most commonly used first line salvage treatment, with the highest ORR of 72.7%, demonstrating a median PFS that was not reached (95% CI 2.03months-NE) and no patients suffered death. Overall, a total of 78 salvage treatment lines were used among the 30 patients at any time post-CAR T relapse with an ORR of 39.4%.

This analysis indicates that Carfilzomib-containing therapy after previous BCMA-targeted treatments offers clinical benefit with higher objective response rates in patients who have few other options.

No relevant conflicts of interest to declare.