Assessment of Salvage Regimens Post-Chimeric Antigen Receptor T Cell Therapy for Patients with Diffuse Large B Cell Lymphoma

Abstract

Anti-CD19 chimeric antigen receptor T cell therapy (CAR19) represents a critical treatment modality for patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). However, the majority of patients subsequently experience disease progression following CAR19, and data are limited on assessing the best salvage regimen for these patients. This study aimed to evaluate outcomes in R/R DLBCL patients with progressive disease post-CAR19 and to assess variables that predict response to salvage therapy. We performed a retrospective analysis of all patients with DLBCL who received CAR19 at our institution between January 2018 and February 2021, collecting data on demographic characteristics, disease characteristics, best response to CAR19, date of relapse or progression, and first salvage therapy and response to salvage. We analyzed patients according to whether they responded to CAR19 (responders) or did not (nonresponders). Salvage regimens were classified into 6 groups for analysis. Primary endpoints included overall survival (OS) and progression-free survival (PFS), calculated using the Kaplan-Meier method. Cox models were fit to evaluate the effect of prognostic factors. Among the 120 patients who received CAR19 during the analysis period were 69 responders who achieved a complete or partial response to CAR19 and 51 nonresponders, including 44 with stable or progressive disease and 7 who died before assessment. Thirty responders relapsed and 26 received salvage therapy, and 24 nonresponders received salvage therapy. The primary salvage regimens included lenalidomide-based regimens (n = 17; 34%), BTKi (n = 10; 20%), checkpoint inhibitor-based (n = 7; 14%), chemo-immunotherapy (n = 5; 10%), allogeneic hematopoietic stem cell transplantation (n = 5; 10%), and others (n = 6; 12%). There was no significant difference in OS based on salvage regimen (P = .4545). Responders who received salvage therapy had significantly longer OS than nonresponders (median OS not reached versus 10.9 months; P = .0187), and response to CAR19 and elevated lactate dehydrogenase level at time of salvage treatment were the only two statistically significant prognostic factors after accounting for other variables. Responders to CAR19 had significantly better outcomes with salvage therapy compared with nonresponders to CAR19. There was no significant difference in outcomes based on salvage regimen. Future research is needed to assess the best salvage regimen post-CAR19 failure.

Keywords: CAR19; Cellular therapy; DLBCL; Outcomes; Relapsed/refractory; Salvage therapy.