∙ \-

∙ Participants must meet all of the following criteria to participate in the study:

• Age ≥18 years old;

• ineligible for autologous transplantation;

• Sign the Informed Consent Form (ICF);

• CD79b-positive DLBCL confirmed by pathology (including transformed DLBCL, PMBL, HGBCL);

• Patients must have received adequate first-line treatment and only first-line treatment, with

‣ Anti-CD20 monoclonal antibodies (unless the investigator determines that the tumor is CD20-negative)

⁃ Chemotherapy regimens containing anthracyclines

• Recurrent or refractory diseases after first-line immunochemotherapy:

‣ Refractory disease is defined as not having a complete response to first-line therapy (except for patients who are intolerant to first-line therapy)

⁃ Recurrent disease is defined as disease recurrence after complete response to first-line treatment

• Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2, with an expected survival of more than 12 weeks.

• Have at least one measurable two-dimensional lesion identified by clinical examination, CT scan or MRI: ① lymph node \>1.5cm; ② Other non-lymph node lesions ≥1.0cm;

• The main tissues and organs function well:

∙ Hematological function: absolute granulocyte count ≥ 1,000/mm3, platelet count ≥ 75,000/mm3; Liver function: ALT/AST \< 3 times upper limit of normal (ULN) and total bilirubin ≤1.5× upper limit of normal (ULN) (\< 5 times ULN in patients with Gilbert syndrome, cholestasis due to hilar compression adenopathy, biliary obstruction due to liver involvement or lymphoma); Renal function: creatinine clearance \> 30 mL/min, creatinine ≤1.5× upper limit of normal (ULN) Lung function: indoor oxygen saturation ≥95%; Cardiac function: no obvious cardiac insufficiency or cardiovascular disease; 10. Fertile patients must be willing to use highly effective contraception during the study period and for 120 days after the last dose of treatment.