Evaluation of Safety and Efficacy of IBI318 Monotherapy for Relapsed/Refractory Extranodal NK/T Cell Lymphoma (Nasal Type) Trial

Inclusion Criteria: 1. Histologically diagnosed as extra-nodal NK/T cell lymphoma (nasal type) according to WHO 2016 criteria; 2. Refractory and relapsed ENKTL patients, being relapsed is defined as re-occurrence of the same lymphoma lesions at the primary site or new sites after complete response (CR); being refractory is defined as having any of the following conditions: evaluated as stable disease (SD) or progression disease (PD) after 2 cycles of treatment; not being able to achieve partial response (PR) after 4 cycles of treatment; not being able to achieve complete response (CR) after 6 cycles of treatment. Patients that did not achieve remission, or relapsed/progressed after autologous stem cell transplantation (ASCT) could also be enrolled. 3. Patients must have received asparaginase-based chemotherapy previously (patients with phase I/II disease must have received radiotherapy previously). 4. With measurable foci, defined as: lymph nodes with long diameters\>15mm，extra-nodal foci\>10mm on CT scan; 5. ECOG PS (Eastern Cooperative Oncology Group Performance Status) point 0 or 1; Exclusion Criteria: 1. Invasive NK cell leukemia; 2. Primary CNS lymphoma or CNS-involved lymphoma; 3. Patients with hemophagocytic syndrome; 4. Patients with lymphoma invading large pulmonary vessels; 5. Patients primarily resistant to anti-PD1,PD-L1,PD-L2 antibodies (generally considered as those received anti- PD1,PD-L1,PD-L2 antibodies as monotherapy or in combination with chemotherapy, but did not achieve PR or CR in non-maintenance treatment).