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 lesion.
* For women of childbearing potential, a negative serum pregnancy test is required (women who have undergone surgical sterilization or are postmenopausal for at least 2 years are considered not to be of childbearing potential).
Exclusion Criteria:
* According to the WHO 2016 classification, patients with the following subtypes are excluded:
* LBCL with T-cell/histiocyte-rich background
* Primary central nervous system DLBCL
* PMBCL (Primary Mediastinal B-Cell Lymphoma)
* B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and classical HL (Hodgkin Lymphoma)
* Burkitt lymphoma
* History of Richter transformation in chronic lymphocytic leukemia
* Presence of detectable malignant cells in the CSF (cerebrospinal fluid), brain metastases, or history of central nervous system involvement by lymphoma.
Presence of cardiac involvement by lymphoma.
* Prior treatment for LBCL other than two cycles of R-chemotherapy.
* History of severe immediate hypersensitivity reaction to any of the drugs used in this study.
* Presence of central nervous system disorders: history of stroke, transient ischemic attack, or reversible posterior leukoencephalopathy syndrome (PRES) within 12 months prior to enrollment.
* History of acute or chronic active hepatitis B or C infection, unless HBV-DNA and HCV-RNA levels are below the level of detection.
* Human immunodeficiency virus (HIV) positivity, unless on appropriate antiretroviral therapy with undetectable viral load by PCR and a CD4 count \> 200 cells/µL.
* Any medical condition that may interfere with the assessment of the safety or efficacy of the study treatment.
* History of clinically significant cardiac disease within 12 months prior to enrollment.
* Any other condition deemed by the investigator as unsuitable for enrollment.
