Pomalidomide Plus Rituximab Maintenance in Young High-Risk Newly Diagnosed DLBCL After First-Line Response

Inclusion Criteria: 1. Age ≥18 years and \<60 years, male or female. 2. Histologically confirmed newly diagnosed diffuse large B-cell lymphoma (DLBCL), with at least a partial response (PR) after first-line therapy. 3. Age-adjusted International Prognostic Index (aaIPI) \>1 at initial diagnosis. 4. Ann Arbor stage II-IV disease at initial diagnosis. 5. Eastern Cooperative Oncology Group Performance Status (ECOG-PS) score of 0-2. 6. Adequate bone marrow hematopoietic function, defined as absolute neutrophil count ≥1.5 × 10\^9/L, with granulocyte colony-stimulating factor support allowed; platelet count ≥75 × 10\^9/L, with platelet transfusion allowed to reach this minimum platelet count; and hemoglobin ≥8.0 g/dL, with prior red blood cell transfusion or recombinant human erythropoietin allowed. If abnormal peripheral blood counts are caused by lymphoma involvement of the bone marrow or spleen, eligibility may be determined at the investigator's discretion. 7. Adequate major organ function, defined as total serum bilirubin ≤2.0 × upper limit of normal (ULN), serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 × ULN, and creatinine clearance \>30 mL/min. For participants with hepatic involvement by lymphoma, eligibility may be determined at the investigator's discretion. 8. Expected survival of ≥3 months as judged by the investigator. 9. Ability to understand the study and willingness to provide written informed consent. 10. Female participants must use effective contraception, must not be pregnant, and must agree n Exclusion Criteria: 1. Presence of another active malignancy that is untreated or currently being treated. 2. History of severe venous thromboembolism (VTE) or cerebral infarction before treatment. 3. Active hepatitis B or hepatitis C infection, or human immunodeficiency virus (HIV) seropositivity. 4. Uncontrolled or severe cardiovascular disease, including myocardial infarction within 3 months before enrollment, unstable coronary artery disease, uncontrolled chronic congestive heart failure, New York Heart Association (NYHA) class III-IV heart failure, or clinically significant pericardial disease. 5. Uncontrolled hypertension or diabetes mellitus. 6. Uncontrolled active infection or acute active infection. 7. Contraindication or allergy to any study drug. 8. Pregnant or breastfeeding women. 9. Any severe physical or psychiatric illness that, in the opinion of the protocol or the investigator, may interfere with participation in this clinical study; or any substance abuse, medical, psychological, or social condition that may interfere with study participation or assessment of study results. 10. Current treatment with other investigational drugs. 11. Participation in another clinical trial within 1 month before enrollment. 12. Any other condition that, in the opinion of the investigator, makes the participant unsuitable for enrollment.