Eligibility Criteria:
Inclusion Criteria:
* They voluntarily participated in the study and signed the informed consent.
* Age 18 or higher;
* Expected survival time for 3 months or more;
* The histopathological diagnosed late relapsed (\> 12 months) diffuse large B cell lymphoma;
* Must have at least a Lugano 2014 standard can be evaluation or measurable lesions: lymph node lesions, measurable lymph nodes should be diameter \> 1.5 cm; Non-lymph node lesions, measurable extranodal lesions should be diameter \> 1.0 cm;
* ECOG score 0 to 2 points;
* Bone marrow function: neutrophil count \>= 1.5 x 10\^9 / L, platelet count \>= 75 x 10\^9 / L, and hemoglobin \>= 80 g/L (neutrophil count may be extended to \>= 1.0 x 10\^9 / L, the platelet count can be extended to \>= 50 x 10\^9 / L, and hemoglobin can be extended to \>= 75 g/L in patients with bone marrow involvement);
* Liver and kidney function: serum creatinine acuities were \<= 1.5 times the upper limit of normal (ULN) value; AST and ALT \<= 2.5 times the ULN(\<= 5 times the upper limit of normal in patients with liver invasion); Total bilirubin \<= 1.5 times the ULN (\<= 3 times the upper limit of normal in patients with liver invasion);
* Blood coagulation function: International standardization Ratio (International Normalized thewire, INR) \<= 1.5 x ULN; Prothrombin Time (PT), Activated PartialThromboplastin Time (APTT) \<= 1.5×ULN (unless receiving anticoagulant therapy, And PT and APTT at screening were within the expected range for anticoagulant therapy).
Exclusion Criteria:
* Previous history of antitumor therapy meeting any of the following conditions:
1. Prior treatment with mitoxantrone or liposomal mitoxantrone;
2. Prior treatment with doxorubicin or other anthracyclines, with a total cumulative doxorubicin dose \>360 mg/m² (for other anthracyclines, 1 mg of doxorubicin is equivalent to 2 mg of epirubicin);
3. Prior autologous hematopoietic stem cell transplantation within 100 days before the first dose, or a history of allogeneic hematopoietic stem cell transplantation;
4. Prior antitumor therapy (including chemotherapy, targeted therapy, hormone therapy, traditional Chinese medicine with antitumor activity, etc.) or participation in other clinical trials involving investigational drugs within 4 weeks or 5 half-lives (whichever is shorter) before the first dose of the study drug.
* Hypersensitivity to any study drug or its components;
* Uncontrolled systemic diseases (e.g., progressive infections, uncontrolled hypertension, diabetes, etc.);
* Cardiac function and diseases meeting any of the following conditions:
1. Long QTc syndrome or QTc interval \>480 ms;
2. Complete left bundle branch block, complete right bundle branch block with left anterior fascicular block, type II second-degree or third-degree atrioventricular block;
3. Severe, uncontrolled arrhythmia requiring medication;
4. New York Heart Association Class ≥ III;
5. History of acute myocardial infarction, unstable angina, severe unstable ventricular arrhythmia, or any other arrhythmia requiring treatment within 6 months before enrollment; history of clinically significant pericardial disease; or electrocardiographic evidence of acute ischemic or active conduction system abnormalities.
* Active hepatitis B or C infection (hepatitis B surface antigen positive with HBV DNA \>1×10³ copies/mL; HCV RNA \>1×10³ copies/mL);
* Human immunodeficiency virus (HIV) infection (HIV antibody positive);
* History or concurrent presence of other malignancies (except for effectively controlled non-melanoma skin basal cell carcinoma, in situ carcinoma of the breast/cervix, and other malignancies effectively controlled without treatment in the past five years);
* Presence of primary or secondary central nervous system (CNS) lymphoma or a history of CNS lymphoma at enrollment;
* Pregnant or lactating women, and patients of childbearing potential unwilling to use contraception;
* Requirement for systemic corticosteroid therapy or other immunosuppressive therapy due to a medical condition within 14 days before the start of study treatment \[topical use (ocular, intra-articular, intranasal, and inhaled corticosteroids with minimal systemic absorption) is permitted; short-term (≤7 days) corticosteroid use for prophylaxis (e.g., contrast agent allergy) or treatment of non-autoimmune conditions (e.g., delayed hypersensitivity due to contact allergens) is permitted\];
* Other conditions deemed by the investigator to be unsuitable for participation in this study.