Sintilimab (IBI308) in Combination With Chidamide and Azacitidine in Refractory or Relapsed PTCL

Inclusion Criteria: * Histopathologically confirmed PTCL; * Disease status defined as relapsed or refractory after \>=1 prior treatment lines; * Prior use of HDACi or PD-1/PD-L1 antibodies or demethylation drugs is allowed; * At least one measurable disease (defined as ≥ 1.5 cm in length-diameter, or 1.1\~1.5 cm in length-diameter and \>1.0 cm in short-diameter ) ； * ECOG PS 0\~2； * Provide written informed consent for the trial； * 18 ≤ age ≤ 80； * Life expectancy ≥12 weeks; * Adequate organ and bone marrow function, laboratory tests should be received within 7 days prior to the use of the research drug and meet the eligibility requirements; * Subjects of reproductive potential must be willing to use adequate contraception during the course of the study and through 120 days after the last dose of study medication. Exclusion Criteria: * Known central nervous system lymphoma or cutaneous T-cell lymphoma; * Received any immunesuppressive drugs within 4 weeks of the first dose of study medicationy, not including topical corticosteroids or systemic corticosteroids in physiological doses (≤10 mg/day prednisone or equivalent dose of other steroid); * Patients with active autoimmune diseases requiring systematic treatment in the past two years; * Received or plan to receive any attenuated vaccines within 4 weeks of the first dose of study medication; * Received the last anti-tumor therapy within 4 weeks of the first dose of study medication or have not recovered (recovery defined as baseline or ≤ grade 1) from adverse events due to anti-cancer agents; * Currently participating in an interventional clinical study, unless participating in observational study or during follow-up period of an interventional study; * Received any investigational agent within 4 weeks of the first dose of study medication; * Subjects with interstitial lung disease or lung disease that may interfere with the detection or treatment of suspected drug-related pulmonary toxicity; * Other primary malignancy; * Known history of allogeneic organ or allogeneic hemopoietic stem cell transplantation; * Received autologous hemopoietic stem cell transplantation within 90 days of the first dose of study medication; * Received major surgery or unhealed wound, ulcer or fracture within 4 weeks of the first dose of study medication; * Active tuberculosis； * Known primary immunodeficiency； * Known allergy or hypersensitivity to any monoclonal antibodies or any components used in their preparation; * Uncontrolled concomitant disease; * Patients with active hepatitis. Patients who are positive for hepatitis B Surface Antigen (HBsAg) or hepatitis C Virus (HCV) antibodies at screening stage must pass further detection of hepatitis B Virus (HBV) DNA titer (no more than 50 IU/mL) and HCV RNA (no more than the lower limit of the detection method); * History of gastrointestinal perforation and /or fistula within 6 months before enrollment; * Hemophagocytic syndrome； * Uncontrolled third space effusion, e.g. ascites or pleural effusion cannot be drained or controlled; * Women who are pregnant or nursing； * According to the researchers' judgment, patients' underlying condition may increase their risk of receiving research drug treatment, or confuse their judgment on toxic reactions; * Other researchers consider it unsuitable for patients to participate in this study.