An Open, Single Center, Non-randomized, Single Arm Clinical Study of Evaluating the Efficacy of Selinexor in the Maintenance Treatment of PTCL

Inclusion Criteria: * Patients fully understand the study, voluntarily participate and sign the informed consent (ICF); * Age range from 18 to 85 years old (including upper and lower limits); * ECOG (Eastern Cooperative Oncology Group) score 0 \~ 2; * PTCL confirmed by histopathology falls into one of the following subtypes according to the WHO classification standard revised in 2016:1) Peripheral T-cell lymphoma non-specific type (PTCL-NOS) 2) vascular immunoblastic T-cell lymphoma (AITL) 3) ALK+ systemic anaplastic large T-cell lymphoma (ALK+ALCL) 4) Alk-systemic anaplastic large T-cell lymphoma (ALK-AlCl) 5) extranasal NK/ T-cell lymphoma (NK/TCL)6) Other subtypes of PTCL that the researchers considered suitable for inclusion. * Subjects achieved complete remission by radiographic assessment at mid-stage. * Subjects must provide a written pathological/histological diagnosis report during the screening period and must agree to provide tumor tissue sections or tumor/lymph node tissue samples for central laboratory testing. * Expected survival is at least 12 weeks. * Patients must meet the following requirements for laboratory tests at screening time and have not received cell growth factor, platelet, or granulocyte infusion within 7 days prior to screening hematological evaluation.1) Neutrophil absolute value ≥1.5×109/L in subjects without bone marrow involvement and ≥1.0×109/L in subjects with bone marrow involvement;2) Hemoglobin ≥90g/L in subjects without bone marrow involvement (in the absence of red blood cell infusion within 14 days), hemoglobin ≥75g/L in subjects with bone marrow involvement;3) Platelets ≥75×109/L in subjects without bone marrow involvement and ≥50×109/L in subjects with bone marrow involvement;4) Serum total bilirubin ≤1.5× upper limit of normal (ULN) (total bilirubin ≤3×ULN if elevated bilirubin level is caused by lymphoma invading the liver);5) Aspartate aminotransferase (AST), alanine aminotransferase (ALT) ≤2.5×ULN;If elevated AST and ALT are caused by lymphoma invading liver, both AST and ALT should be ≤5×ULN).6) Creatinine \<1.5×ULN. * Eligible patients (male and female) who are fertile must agree to use a reliable contraceptive method (hormonal or barrier method or abstinence) with their partner during the trial period and for at least 7 months after the last medication;Female patients of reproductive age must have had a negative blood pregnancy test within 14 days prior to inclusion. Exclusion Criteria: * Patients with leukemic PTCL (such as adult T-cell leukemia/lymphoma, etc.), or lymphoma leukemia stage (bone marrow examination lymphoma cell proportion ≥20%), or central nervous system (CNS) involvement, or complicated hemophagocytic syndrome. * Allergic history to similar drugs and excipients of the study drug. * Participated in other clinical studies and used the study drug within 4 weeks prior to the first administration of the study drug. * The toxic reactions of previous antitumor therapy have not recovered, and there are still more than grade 1 toxic reactions, except hair loss and pigmentation. * Impaired heart function or significant heart disease, including but not limited to: 1) myocardial infarction, congestive heart failure, viral myocarditis in the 6 months prior to screening;Heart disease with symptoms that require therapeutic intervention, such as unstable angina, arrhythmia, etc.;2) Cardiac function grade Ⅱ to Ⅳ (New York College of Cardiology Cardiac Function Grade NYHA);3) Echocardiographic examination of cardiac ejection fraction (EF) below 50% or below the lower limit of laboratory test value; * Active hepatitis B (surface antigen positive with HBV-DNA titers higher than 2000IU/ml) or hepatitis C (HCV antibody positive with HCV ribonucleic acid (HCV RNA) titers higher than the upper limit of the study center's normal). * History of severe autoimmune diseases and immunodeficiency, including positive human immunodeficiency virus (HIV) antibodies;Or other acquired or congenital immunodeficiency diseases;Or have a history of organ transplantation. * History of other malignant tumors within 5 years (except cured basal cell carcinoma of the skin and carcinoma in situ of the cervix). * Major surgery was performed within 6 weeks prior to screening or was expected to be performed during the study period. * There are significant gastrointestinal disorders at the time of screening that may affect drug intake, transport or absorption (e.g., inability to swallow, chronic diarrhea, intestinal obstruction, etc.). * Uncontrolled hypertension (refers to patients with type 2 diabetes whose blood pressure still reaches the level 3 hypertension standard after antihypertensive treatment, with systolic blood pressure ≥180mmHg and/or diastolic blood pressure ≥110mmHg) or who cannot be controlled by oral hypoglycemic drugs and insulin therapy. * History of active bleeding within 3 months prior to screening. * History of mental illness or psychotropic substance abuse or dependence. * Pregnant or lactating women. * Other conditions considered inappropriate for participation in the study