3766 - Safety and Efficacy of Bridging Radiation Therapy for Refractory/Relapsed Diffused Large B-cell Lymphoma: Systematic Review and Meta-Analysis
Presenter(s)
Y. Zhou1, Y. X. Li2, Q. Xiao1, and J. Jin1; 1National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Shenzhen, China, 2National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, Guangdong, China
Purpose/Objective(s): CD19-targeted chimeric antigen receptor T cell (CART) therapy has revolutionized the treatment paradigm for patients with relapsed or refractory diffused large B-cell lymphoma (R/R DLBCL). Bridging radiotherapy (BRT) prior to CAR-T infusion has been increased used for disease control or palliation during the manufacturing period. However, the potential additive or synergistic effect of adding RT to CART remains unclear. This study aimed to investigate the efficacy and safety of BRT in patients with R/R DLBCL thought a systematic review and meta-analysis.
Materials/Methods: Clinical studies on BRT for R/R DLBCL were searched from the PubMed, Embase, MEDLINE, and Cochrane Library databases. The primary outcomes were overall response (ORR) rate, complete response (CR) rate, and severe adverse events, including grade = 3 cytokine release syndrome (CRS) and effector cell-associated neurotoxicity syndrome (ICANS). The second outcomes including progression-free survival (PFS) and overall survival (OS). Fixed and random effects models were used to estimate pooled proportions and risk ratios (RRs) with 95% confidence intervals (CI). All analysis were performed using R-4.1.0 software.
Results: A total of 31 studies comprising 2726 patients were included. The pooled incidence of Grade = 3 CRS and ICANS was 3.7% and 9.8% in patients received BRT, which is comparable to bridging system therapy (BST) (4.9% and 12.0%; CRS: RR = 1.08, 95% CI 0.66-1.78; ICANS: RR = 0.93, 95% CI 0.66-1.30), and no bridging therapy (noBT) (6.5% and 13%; CRS: RR =1.20, 95% CI 0.56-2.56; ICANS: RR = 1.02, 95% CI 0.64-1.60). The baseline characteristics of patients vary across different bridging groups. In the BRT and BST groups, a higher proportion of patients present with high-risk factors, including stage III-IV disease, IPI scores = 3, bulky disease and extra-nodal invasion, although the proportion was similar between the two groups. In contrast, the noBT group has a significantly lower proportion of patients exhibit these high-risk factors. However, the results showed that BRT group achieved higher ORR rate and CR rate compare to BST group (ORR: RR = 2.73, 95% CI 1.63-4.58; CR: RR = 2.72, 95% CI 1.52-4.89), and comparable ORR rate and CR rate compare to noBT group (ORR: RR = 1.15, 95% CI 1.04-1.27, CR: RR = 1.25, 95% CI 1.01-1.55). The pooled ORR rate and CR rate were 77.5% and 52.6%, 67.0% and 41.8, 80.1% and 55.9% in BRT group, BST group and noBT group, respectively. The pooled 1-year OS and 1-year PFS were 72.8% and 53.2% in BRT group, 53.1% and 38.1% in BST group, and 68.4% and 50.9% in noBT group.
Conclusion: Our study shows that BRT is a promising therapy with higher responses rate and similar severe side effects compare to BST and noBT for patients with R/R DLBCL, worthing further investigation in a prospective setting.