This is a single-arm, prospective, multicenter, open-label phase Ib/II study to evaluate the safety and efficacy of polatuzumab vedotin in combination with rituximab and chidamide in previously untreated elderly patients with MYC/BCL2 double-expressor diffuse large B-cell lymphoma.

Inclusion Criteria:

• Voluntarily participate in the clinical study; fully understand and be informed about the study and sign the Informed Consent Form (ICF); willing to comply with and capable of completing all trial procedures;
• Age ≥70 years, or age 60-69 years with frailty determined by comprehensive geriatric assessment (CGA).
• Pathologically confirmed diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS) with MYC/BCL2 double expression, and no double-hit or triple-hit lymphoma.
• At least one measurable or evaluable lesion according to the Lugano 2014 criteria.
• No prior systemic therapy for DLBCL.
• Adequate organ and bone marrow function.

Exclusion Criteria:

• Other subtypes of DLBCL.
• Lymphoma involvement in the central nervous system or meninges.
• Active infections.
• History of Human Immunodeficiency Virus (HIV) infection and/or Acquired Immunodeficiency Syndrome (AIDS).
• Patients with mental disorders or those unable to provide informed consent
• Any other condition deemed by the investigator to be unsuitable for study enrollment.
• Known hypersensitivity to any investigational drug.