Abstract
Background:
B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor T-cell (CAR T-cell) therapy has exhibited remarkable efficacy in refractory or relapsed multiple myeloma (R/R MM), but recurrence and rapid progression of disease are still observed within a short time after treatment. Long-term pomalidomide therapy, which potentiates T-cell functionality, might enhance the efficacy of BCMA CAR T-cell therapy.
Methods:
We performed a single-center retrospective clinical study. Patients with relapsed or refractory multiple myeloma who received BCMA CAR T-cell infusion were enrolled in our study, and were followed by long-term pomalidomide treatment (4 mg/day) or not one month after infusion. The response and adverse events were assessed after infusion. The effect of pomalidomide on BCMA CAR T-cells was assessed in vitro.
Results:
The objective response rate (ORR) of BCMA-CART was 100%. Three months following CAR T-cell infusion, of the 8 patients receiving pomalidomide, except for 2 patients who stopped maintenance therapy and were lost to follow-up, all patients (6/6) achieved VGPR (very good partial response) or CR (complete response), while only 5 patients (5/8) who did not receive pomalidomide treatment achieved VGPR or better. At a median follow-up of 27 months, for the 8 patients who did not receive pomalidomide administration, the median TTP (time to progression) was 5.85 (1-14) months, while the OS (overall survival) was 10.7 (1.2-16) months. Of the 8 patients who received pomalidomide therapy after CAR T-cell infusion, the median TTP was 13 (7-13) months, while the OS was not reached. Moreover, neither long-term hematological toxicity nor drug-induced liver damage was observed during the follow-up period. Mechanistically, pomalidomide promotes antimyeloma efficacy of BCMA CAR T-cells by inhibiting cell apoptosis and enhancing cytoxicity.
Conclusions:
Our results confirmed that BCMA CAR T-cell therapy combined with long-term pomalidomide had a low recurrence rate and manageable therapy-related side effects, providing a promising option for treating R/R MM.