Positron Emission Tomography Evaluation in Relapsed/Refractory B-Cell Lymphoma Patients Treated with Anti-19 Chimeric Antigen Receptor (CAR) T-Cells in the CART-SIE Observational Study

Background: CD19 direct chimeric antigen receptor (CAR) T-cell therapy is an efficacious therapy for patients (pts) affected by relapsed/refractory (R/R) large B-cell lymphomas (LBCL). The role of early evaluation by Positron emission tomography/computed tomography (PET/CT) is still undefined. The study's objective was to analyze the role of early PET/CT according to histology and CAR T-cell product administered. Methods:CART-SIE is an ongoing prospective and retrospective observational study evaluating the outcome of lymphoma pts treated with CAR T-cells. From March 2019 to June 2023, 659 patients were enrolled. In this study, we included only pts with adequate follow-up (30 days) and an FDG-PET/CT before infusion (PET-0) and at least one month (PET-1) after CAR-T cells infusion. A landmark analysis based on PET-1 and PET-3 (3 months evaluation) results was performed for Progression-free survival (PFS) and Overall Survival (OS) estimation. Results: Three hundred twenty-seven pts with R/R LBCL [n= 189 (58%) Diffuse large B-cell lymphomas, n= 59 (18%) High-grade B-cell lymphomas (HGBCL), n= 41 (13%) Primary Mediastinal B-cell lymphomas (PMBCL), n= 38 (11%) Mantle Cell Lymphoma (MCL)] received CAR T-cell treatment with axicabtagene-ciloleucel [n=161(49%), axicel], tisagenlecleucel [n=128 (39%), tisacel] or brexucabtagene autoleucel [n=38(12%), brexucel]. The median age of the pts was 58 years (90 pts were older than 65 years). Most pts [n=280, (85,6%)] were treated with a bridging therapy. Bulky and extranodal disease were observed in 108 (33%) and 177 (54,1%) pts, respectively. Pts who received tisacel were significantly older (p