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

PRIMARY OBJECTIVES: To determine the objective response rate (ORR). SECONDARY OBJECTIVES: 1. To determine the complete response rate (CRR). 2. To determine the duration of response (DOR). 3. To determine the progression free survival (PFS). 4. To determine the overall survival (OS). 5. To determine the safety. EXPLORATORY OBJECTIVES: Assess the correlation between the expression of PD-L1, CD4, CD8, CD68 in tumor microenvironment and the efficacy of combined therapy in relapsed or refractory peripheral T-cell lymphoma.