Differences Between Chidamide Taken Daily and Twice a Week in Therapeutic Effect，Pharmacokinetics, Pharmacodynamics and EB Virus Activation

Inclusion Criteria:

1. NKTCL patients confirmed by histopathology examination.
2. Age 18-75 years old, male or female, fertile women should have effective contraceptive measures.
3. NT/T cell lymphoma patients with disease progression or non-remission after L-asparaginase treatment or L-asparaginase-contained regimen treatment. Non-remission is defined as: patients do not have partial remission (PR) or better responses after treated by L-asparaginase contained regimen.
4. Patients who had 1-3 regimens (including chemotherapy, stem cell transplantation), but did not achieve remission or relapsed after remission.
5. With at least 1 measurable focus, whose long diameter ˃ 1.5cm, short diameter ˃1.0cm, or at least one evaluable focus.
6. Body weight: male 67±20 kilograms (47-87 kg), female 55±20 kilograms (35-75 kg);
7. Blood-routine test within 14 days of enrollment should satisfy (except lymphoma-related abnormalities): Hb≥80g/L，ANC≥1.0×109/L，PLT≥75×109/L；
8. ECOG: 0-2;
9. Estimated survival ≥ 3 months;
10. Willing to sign the written consent before the trial.

Exclusion Criteria:

1. Women during pregnancy or lactation, or fertile women unwilling to take contraceptive measures.
2. QTc elongation with clinical significance ( male˃ 450ms, female˃ 470ms), ventricular tachycardia, atrial fibrillation, cardiac conducting blockage, myocardial infarction within 1 year, congestive heart failure, symptomatic coronary heart disease that requires treatment.
3. Cardiac B ultrasound show end-diastolic pericardial dark zone≥ 10cm
4. Patients who have received organ transplantation.
5. Patients received symptomatic treatment for bone marrow toxicity within 7 days prior to enrollment.
6. Patients with active hemorrhage.
7. Patients with or with history of thrombosis, embolism, cerebral hemorrhage, or cerebral infarction.
8. Patients with active infection, or with continuous fever within 14 days prior to enrollment.
9. Had major organ surgery within 6 weeks prior to enrollment.
10. Abnormal blood routine test results within 14 days prior to enrollment (Hb˂80g/L，ANC˂1.0×109/L，PLT˂75×109/L； Impaired liver function ( Total bilirubin ˃ 1.5 times of normal maximum, ALT/AST˃ 2.5 times of normal maximum, for patients with infiltrative liver disease ALT/AST ˃ 5 times of normal maximum), impaired renal function (serum creatinin˃ 1.5 times of normal maximum).
11. Patients with history of Chidamide treatment and had disease progression within 6 months afterward;
12. Patients that received large dose of steroids (˃10mg/d dexamethasone or other steroids of the equivalent dosage) within 4 weeks prior to enrollment;
13. Patients with hemophagocytic syndrome;
14. Patients with central nerve system diseases or history of central nerve system diseases;
15. Patients with mental disorders or those do not have the ability to consent;
16. Patients that had been enrolled in other clinical trials within 3 months prior to enrollment;
17. Patients with drug abuse, long term alcoholism that may impact the results of the trial.
18. Non-appropriate patients for the trial according to the judgment of the investigators.