• ≥18 years old.

• Capable of understanding and voluntarily signing written informed consent.

• ECOG performance 0 \

• Anticipated survival ≥3 months

• Histologically or cytologically confirmed DLBCL.

• PET-CT-defined measurable disease with a short axis diameter of ≥1.5 cm.

• Have received at least one prior line of systemic therapy for DLBCL.

• Resolution of any prior treatment-related non-hematologic toxicities to Grade ≤1 or baseline.

• Adequate Bone Marrow and Organ Function, defined as:

• Bone Marrow Function: ANC≥1.5 × 10⁹/L, Platelets ≥80 × 10⁹/L, Hemoglobin ≥80 g/L Hepatic Function: Total bilirubin ≤1.5 × ULN (≤3.0 × ULN if liver metastases present); AST/SGOT and ALT/SGPT ≤2.5 × ULN (≤5.0 × ULN if liver metastases present) Coagulation: INR and aPTT≤1.5 × ULN Renal Function: Serum creatinine ≤1.5 × ULN or estimated creatinine clearance (CrCl) ≥60 mL/min;

⁃ Subjects with childbearing or childbearing potential must be willing to practice birth control from the date of registration in this study to the follow-up period of the study.

⁃ Able to swallow tablets/capsules without difficulty.

⁃ Adhere to scheduled visits, treatment plans, laboratory tests, and other study procedures.