Sintilimab Plus R-GemOx as Second-line Salvage Therapy in Patients With R/R DLBCL

This study evaluates the addition of Sintilimab to current 2nd line salvage therapy of Rituximab, Gemcitabine and Oxaliplatin (R-GemOx) for patients with relapsed or refractory Diffuse Large B-Cell Lymphoma (DLBCL). All patients will receive four cycles of sintilimab plus R-GemOx. Afterwards, 1) patients who achieve CR assessed by PET-CT and are eligible for autologous stem cell transplantation (ASCT) will undergo ASCT. After transplantation, patients will receive sintilimab monotherapy up to 8 cycles or until disease recurrence and progression, death, intolerance and toxicity, withdrawal of informed consent, or other reasons specified in the protocol. 2) Patients who achieve CR assessed by PET-CT and are not eligible for ASCT will directly receive sintilimab monotherapy as maintenance treatment for a maximum of 8 cycles as described above. 3) Patients achieved PR, SD or PD assessed by PET/CT will withdraw from this study and receive proper treatment based on investigator\'s decision.