A multicenter retrospective study of HDAC inhibitor- based regimen for relapsed/refractory non-hodgkin lymphoma patients post CAR-T therapy

CD19-directed CAR-T therapy has demonstrated remarkable efficacy in patients with relapsed/refractory large B-cell lymphoma, but most patients eventually relapse, and optimal salvage treatment strategies after CAR-T therapy failure are limited. A total of 27 salvage regimens were subsequently implemented in 55 patients whose CAR-T therapy failed. The median overall survival (OS) from post CAR-T therapy was 8.5 months (95% confidence interval [CI] 5.6–11.0). The overall response rate (ORR) to salvage therapy was 30.91% (complete remission [CR] 18.18%; partial response [PR] 12.73%), with a median event-free survival of 2.43 months (95% CI 1.77–5.20). 25 patients (25/55, 45.45%) received chidamide-based therapy as salvage treatment, and the CR rates of salvage therapies ranged from 28% with chidamide-based strategies to 10% with nonchidamide-based strategies. Moreover, the ORR rates of patients in the chidamide-based group and nonchidamide-based group were 44% and 20%, respectively. Patients treated with chidamide-containing regimens had significantly longer median OS and event-free survival (EFS) (10.10 months and 6.23 months) than their counterparts receiving nonchidamide therapies (6.07 months and 1.53 months, respectively). Patients with large B-cell lymphoma who relapse after CD19 CAR-T therapy have a limited prognosis but can potentially be treated with various salvage therapies, and chidamide-based therapy may induce a better response in this setting.