The purpose of this study is to evaluate the efficacy and safety of sugemalimab (CS1001) in combination with PGemOx regimen (pegaspargase, gemcitabine, oxaliplatin) in treatment of adult patients with Extranodal NK/T-Cell Lymphoma (ENKTL) who have relapsed or become refractory to asparaginase-based regimens.
Has ENKTL histologically confirmed by the study center. Nasal and non-nasal ENKTL are both allowed.
Has relapsed or refractory ENKTL after prior asparaginase-based chemotherapy or chemoradiotherapy.
Has Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2.
Has at least one measurable lesion per Lugano 2014 classification.
Has aggressive natural killer-cell leukemia, current central nervous system (CNS) involvement or is concomitant with hemophagocytic lymphohistiocytosis.
Has known additional malignancy within 5 years prior to randomization.
Has an active autoimmune disease or has had an autoimmune disease that may relapse.
Has had a major surgical procedure within 28 days or radiotherapy within 90 days before the first dose of study treatment.