The Efficacy and Safety of the RCMOP Sequential Therapy as a First-line Treatment for Patients With Intermediate-to-high Risk Diffuse Large B-cell Lymphoma Who Had Incomplete Remission.

Inclusion Criteria:

1. Subjects fully understand and voluntarily participate in this study and sign informed consent
2. Age≥18 years old
3. International Prognostic Index (IPI)\>2
4. Expected survival ≥ 3 months
5. DLBCL initially diagnosed by histopathology meets the following subtypes according to the 2016 WHO classification: (1) Germinal center B-cell-like (GCB) subtype; (2) Non-germinal center B-cell-like (non-GCB) subtype
6. Patients who were evaluated as incomplete remission after 2 cycles of RCHOP/RCDOP for initial treatment
7. At least 1 evaluable or measurable lesion meeting Lugano 2014 criteria: Nodal lesion: Greatest transverse diameter\>1.5cm; Extra-nodal lesion: Greatest transverse diameter\>1.0cm
8. ECOG Performance Status: 0-1
9. Bone marrow function: Absolute neutrophil count ≥1.5×10\^9/L, Platelet count ≥75×10\^9/L, Hemoglobin ≥ 80g/L (Patients with bone marrow involvement were judged by the investigator to enter the group)
10. Liver and kidney function: serum creatinine ≤ 1.5×ULN (upper limit of normal); AST and ALT ≤ 2.5×ULN (≤ 5×ULN for subjects with liver metastases); total bilirubin ≤ 1.5×ULN (≤ 3×ULN for subjects with liver metastases).

Exclusion Criteria:

1. Hypersensitivity to any study drug or its components
2. Uncontrolled systemic diseases (such as active infection, uncontrolled hypertension, diabetes, etc.)
3. Heart function and disease meet one of the following conditions: (1) Long QTc syndrome or QTc interval \> 480 ms; (2) Serious and uncontrolled arrhythmias requiring drug treatment, uncontrolled angina with poor drug control and myocardial infarction within 6 months before enrollment; (3) New York Heart Association grade III\~IV; (4) Cardiac ejection fraction (LVEF)\< 45%
4. Hepatitis B and hepatitis C active infection (HBV DNA above upper limit of normal; HCV antibody positive and HCV RNA above upper limit of normal)
5. Human immunodeficiency virus (HIV) infection (HIV antibody positive)
6. Subjects with other malignant tumors past or present (except for non-melanoma skin basal cell carcinoma, breast/cervical carcinoma in control, and other malignant tumors that have been effectively controlled without treatment within the past five years)
7. Subjects suffering from primary or secondary central nervous system (CNS) lymphoma
8. pregnancy, lactation and patients of childbearing age who are unwilling to take contraceptive measures
9. Mental patients or those who cannot obtain informed consent
10. Unsuitable subjects for this study determined by the investigator.