Study to Evaluate the Efficacy and Safety of Axicabtagene Ciloleucel Injection as First-Line Therapy of High-Risk Large B-Cell Lymphoma

Inclusion Criteria: * Histologically confirmed LBCL (Large B-Cell Lymphoma) according to the WHO 2016 classification, including the following subtypes:DLBCL-NOS (Diffuse Large B-Cell Lymphoma, Not Otherwise Specified),HGBL (High-Grade B-Cell Lymphoma, including HGBL with MYC, BCL-2, and/or BCL-6 rearrangements (DHL/THL), HGBL-NOS),DLBCL transformed from follicular or marginal zone lymphoma, eligible if the patient has not previously received anthracycline-containing therapy * International Prognostic Index (IPI) score of 2-5 at initial diagnosis. * Individuals must have a positive interim positron emission tomography (PET) (Deauville PET score of 4 or 5) after 2 cycles (PET2+) of chemoimmunotherapy or high-risk ctDNA status (ctDNA levels not reduced by at least 2-log after two cycles of R-chemotherapy) * Age of 18 years or older. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2. * Adequate renal, hepatic, pulmonary, and cardiac function, defined as: * Creatinine clearance (estimated by Cockcroft-Gault formula) ≥ 60 mL/min * Serum ALT/AST ≤ 2.5 × Upper Limit of Normal (ULN) * Total bilirubin ≤ 1.5 × ULN (except for patients with Gilbert's syndrome) * Left ventricular ejection fraction ≥ 50%, no pericardial effusion as determined by echocardiography, and no clinically significant arrhythmias No clinically significant pleural effusion * Baseline peripheral oxygen saturation \> 92% under room air ventilation * At least one measurable lesio…