Lisaftoclax Plus Chidamide and Rituximab in Relapsed or Refractory Diffuse Large B-cell Lymphoma

Inclusion Criteria: * Age ≥18 years. * Histologically confirmed diffuse large B-cell lymphoma (DLBCL) according to the 2016 WHO classification with BCL-2 positivity by immunohistochemistry (defined as BCL-2 expression ≥30%). * Relapsed or refractory DLBCL after prior treatment with an anthracycline-containing regimen and an anti-CD20 antibody-containing regimen. * Received at least one prior line of therapy and considered ineligible for autologous stem cell transplantation (ASCT). * Estimated life expectancy ≥3 months. * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. * At least one measurable or evaluable lesion according to the Lugano 2014 lymphoma response criteria. * Adequate bone marrow, hepatic, and renal function. * Ability to understand and willingness to voluntarily sign a written informed consent form. Exclusion Criteria: * Central nervous system (CNS) involvement by lymphoma, primary CNS lymphoma, or leukemic phase lymphoma. * Prior intolerance to BCL-2 inhibitors and chidamide, or disease refractory to or relapsed after treatment with both agents. * Known hypersensitivity to any component of the study drugs or their analogs. * Prior allogeneic hematopoietic stem cell transplantation within 6 months before the first dose, active graft-versus-host disease (GvHD), or requirement for immunosuppressive therapy within 28 days prior to study treatment. * Clinically significant active cardiovascular disease. * Uncontrolled or clinically unstable infection requiring parenteral antibacterial, antiviral, or antifungal therapy within 7 days before the first dose of study treatment. * Pregnant or breastfeeding women. * Active human immunodeficiency virus (HIV) infection and/or acquired immunodeficiency syndrome (AIDS). * Malabsorption syndrome or other conditions that may interfere with enteral administration or absorption of study drugs. * Any other medical, psychiatric, or social condition that, in the investigator's judgment, would make the subject inappropriate for participation in this study.