A Phase II Study of Axicabtagene Ciloleucel, an Anti-CD19 Chimeric Antigen Receptor (CAR) Tcell Therapy, in Combination With Radiotherapy (RT) in Relapsed/Refractory Follicular Lymphoma

Primary Objectives: The primary objective of this study is to determine the safety of standard of care axicabtagene ciloleucel with bridging radiotherapy (RT) in patients with relapsed or refractory follicular lymphoma, as assessed by the incidence of grade 3 or higher cytokine release syndrome (CRS) within 30 days after chimeric antigen receptor (CAR) T-cell infusion. Secondary Objectives: * Establish the rates of CRS and ICANS in patients treated with CAR T-cell therapy and radiation * Determine complete response rate (CR) at approximately 1 month post CAR T-cell ---therapy * Determine complete response rate (CR) at approximately 6 month post CAR T-cell ---therapy * Determine the overall response rate (ORR) * Determine the duration of response (DOR) * Determine progression free survival (PFS) * Determine overall survival (OS) Exploratory Objectives: * Assess the impact of tumor burden as measured by metabolic tumor volume and total lesion glycolysis on PET/CT on response following CAR T-cell infusion * Assess T-cell fitness from blood samples by flow cytometry and ssRNAseq prior to and after bridging RT * Perform immune profiling of blood samples for T-cell subsets prior to and after bridging RT * Assess cytokine profile after infusion