Selinexor in Combination With R-CHOP Followed by Selinexor Maintenance for Untreated EBV-positive DLBCL Patients

Inclusion Criteria:

1. Subjects fully understand and voluntarily participate in this study and sign informedconsent
2. Age ≥18, ≤70 years, no gender limitation.
3. Histologically confirmed diagnosis of EBV-positive diffuse large B-cell lymphoma (DLBCL) (more than 50% of tumor cells are positive with EBV encoded small RNAs (EBERs)in situ hybridization were considered EBERs positive).
4. Untreated patients, except for the short-time use of prednisone for controllingtumor-induced symptoms (no more than 30mg/d (or other equivalent amounts of otherglucocorticoids), no more than 7 days).
5. There must be at least one measurable or evaluable lesion that meets the evaluationcriteria for Lugano 2014 lymphoma: measurable lesion: Positron emissiontomography/computed tomography (PET/CT) or CT and/or MRI, intranodal lesions with longdiameter >1.5cm, and short diameter >1.0cm, or extranodal lesions with long diameter > 1.0 cm.
6. Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0-2.
7. Expected survival ≥ 3 months.
8. Adequate function of bone marrow: White blood cell ≥3.0×10E9/L, absolute neutrophil count ≥1.5×10E9/L Platelet ≥100×10E9/L (Bone marrow invasive patient≥75×109/L) Hemoglobin≥ 90g/L No granulocytegrowth factor, platelet, or red blood cell transfusions were received within 14 daysprior to examination.
9. Adequate function of the liver and renal: Total bilirubin≤2×upper limit of normal (ULN) (patients with liver invasion or Gilbertsyndrome ≤5×ULN) Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5×ULN (patients with liver invasion ≤5×ULN) Serum creatinine ≤1.5×ULN or creatinineclearance rate ≥60 mL/min
10. The patients agree to take effective contraceptive measures during the study periodand till 12 months after the last administration of the study treatment.

Exclusion Criteria:

1. EBV-positive DLBCL combined with other types of lymphoma. Transformed DLBCL.
2. EBV-positive DLBCL with central nervous system invasion.
3. The patients had previously received XPO1 inhibitors, such as selinexor and so on.
4. The patients have contraindications to any drug in the combined treatment.
5. The major surgery is performed within 4 weeks before enrollment, except for diagnosis.
6. There are any life-threatening diseases, medical conditions or organ systemdysfunction that the investigator believes may affect the safety or compliance ofpatients.
7. Heart function and disease meet one of the following conditions:
8. Heart failure with the classification of New York Heart Association heartfunction of grade II;
9. A history of unstable angina pectoris;
10. A history of myocardial infarction within the past 1 years;
11. Patients with clinically significant supraventricular or ventricular arrhythmiarequiring treatment or intervention;
12. A history of other malignant tumors within the past 5 years (except the cured cervicalcancer and basal cell carcinoma of the skin).
13. Patients with active bleeding.
14. Uncontrolled infection exists within 7 days before treatment and parenteralantibiotics, antiviral drugs or antifungal drugs are needed; However, preventive useof these drugs (including parenteral anti-infective drugs) is allowed.
15. Patients with chronic active hepatitis B or active hepatitis C. If the backgroundhepatitis B Surface Antigen (HBsAg) and/or hepatitis B core Antibody (HBcAb) orhepatitis C Virus (HCV) antibody are positive, the further determination for HepatitisB Virus (HBV) DNA (no more than 2500 copies /mL or 500 IU/mL) and HCV RNA (no morethan the lower limit of the assay) can be included. The patients with HBsAg and/orHBcAb positive need to receive anti-HBV drugs.
16. Patients with the infection of human immunodeficiency virus (HIV) and/or acquiredImmunodeficiency syndrome.
17. Inability to swallow tablets, presence of malabsorption syndrome, or any othergastrointestinal disease or dysfunction that may affect the absorption of the studydrug.
18. Pregnant and lactating women, and subjects of childbearing age who do not want to usecontraception.
19. Mentally ill persons or persons unable to obtain informed consent.
20. The investigators think that the patient is not suitable for the study.