Phase Ib/II Study of Polatuzumab Vedotin in Combination With Rituximab and Chidamide in Newly Diagnosed Elderly Patients With Double-Expressor DLBCL

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.