Efficacy and safety of chidamide in combination with the R-mini CHOP regimen, followed by chidamide plus CD20 monoclonal antibody as maintenance therapy, in elderly patients with newly diagnosed MYC/BCL2 double-expressor DLBCL.

The primary study objective is to evaluate the 2-year progression-free survival (PFS) rate of chidamide in combination with the R-miniCHOP regimen. Secondary objectives include the objective response rate (ORR), duration of response (DOR), complete response (CR) rate, the percentage of patients converting from PR/SD to CR/PR, overall survival (OS), and safety parameters. The exploratory objective is to investigate the correlation between biomarkers (e.g., tumor genomics, proteomics) and ctDNA with treatment efficacy.

Inclusion Criteria:

1. Age ≥ 70 years;
2. No prior treatment for DLBCL;
3. Histopathologically confirmed diagnosis (all of the following conditions must be met simultaneously): ① Diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), and CD20-positive; ② "MYC/BCL2 double-expressor": Immunohistochemistry (IHC) per WHO criteria: MYC ≥ 40%, and BCL2 ≥ 50%; ③ Non-"double-hit" or "triple-hit" lymphoma;
4. At least one 18F-fluorodeoxyglucose (18FDG)-avid lesion on positron emission tomography-computed tomography (PET-CT) according to the 2014 Lugano classification for Hodgkin and non-Hodgkin lymphoma;
5. International Prognostic Index (IPI) score > 1;
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2;
7. At screening, laboratory tests must meet the following criteria, unless judged by the investigator to be due to lymphoma (no corrective or supportive treatment for the indicators below within 2 weeks prior to assessment): ① Hematology: Hemoglobin (Hb) ≥ 90 g/L, Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L, Platelet count (PLT) ≥ 90 × 10⁹/L; ② Biochemistry: Serum creatinine (Cr) ≤ 1.5 × upper limit of normal (ULN); Total bilirubin (TBIL) ≤ 1.5 × ULN; Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN (≤ 5 × ULN in cases of liver metastasis);
8. Life expectancy ≥ 6 months;
9. Understand and voluntarily sign a written informed consent form.

Exclusion Criteria:

1. Central nervous system (CNS) involvement;
2. Transformed lymphoma, i.e., lymphoma transformed from other lymphoma types such as follicular lymphoma, marginal zone B-cell lymphoma, or chronic lymphocytic leukemia/small lymphocytic lymphoma; specific subtypes of DLBCL (e.g., primary CNS DLBCL, etc.);
3. Uncontrolled cardiovascular or cerebrovascular diseases, coagulation disorders, autoimmune diseases, or severe infectious diseases;
4. History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies, or known sensitivity or allergic reactions to murine products; contraindications to any component of the CHOP regimen or chidamide;
5. HIV/HCV infection;
6. If HBsAg is positive, HBV DNA testing is required; patients with negative DNA may be enrolled. If HBsAg is negative but HBcAb is positive (regardless of HBsAb status), HBV DNA testing is required; patients with negative DNA may be enrolled.
7. Uncontrolled cardiovascular or cerebrovascular diseases, coagulation disorders, autoimmune diseases, or severe infectious diseases;
8. Inability to comply with the study protocol due to psychiatric or other unknown reasons;
9. For female patients of childbearing potential or male patients with partners of childbearing potential, unwillingness or inability to use effective contraception throughout the study treatment period and for 12 weeks after the last dose of chidamide or 12 months after the last dose of rituximab, whichever is longer; pregnant or breastfeeding women;
10. Other conditions deemed unsuitable for participation in this trial.