Penpulimab Plus R2-GemOx Regimen in Relapsed or Refractory DLBCL

This study evaluates the efficacy and safety of penpulimab plus lenalidomide, rituximab, gemcitabine and oxaliplatin (R2-GemOx) in patients with relapsed/refractory diffuse large B cell lymphoma (DLBCL). All patients will receive six cycles of penpulimab plus R2-GemOx. Afterwards, 1) patients who achieve complete response (CR)/unconfirmed (CRu)/partial response (PR) assessed by positron emission tomography/computedtomography (PET-CT) and are eligible for autologous stem cell transplantation (ASCT) will undergo ASCT. 2) Patients who achieve CR/CRu/PR assessed by PET-CT and are not eligible for ASCT will directly receive penpulimab and lenalidomide as maintenance treatment, penpulimab for a maximum of 6 months, lenalidomide monotherapy for 18 months. 3) Patients achieved stable disease (SD) or progression disease (PD) assessed by PET-CT will withdraw from this study and receive proper treatment based on investigator's decision.