Anti-PD-1 antibody (Tislelizumab) combined with gemcitabine and oxaliplatin for extranodal NK/T-cell lymphoma failing asparaginase: A multicenter phase II trial

Background: Extranodal natural killer/T-cell lymphoma (ENKTCL) is almost always fatal after the failure of asparaginase. This phase II study aimed to investigate the efficacy and safety of tislelizumab combined with gemcitabine and oxaliplatin (Tisle-GemOx) in patients with ENKTCL failing asparaginase. Methods: Eligible patients received Tisle-GemOx as initial induction for 6-8 cycles at 21-day intervals. Responders continued tislelizumab maintenance every two months for two years. The primary endpoint was the best complete response rate (CRR). Results: As of September 2023, 32 patients were enrolled in our study. Among the 30 efficacy-evaluable patients, the best CRR was 60 %, meeting the primary efficacy endpoint. With a median follow-up of 22.6 months, the median progression-free survival (PFS) was 7.4 months and the 1-year PFS rate was 46.4 %. Subgroup analyses showed that shorter PFS was associated with previous lines of chemotherapy >= 2 (P = 0.034) and concomitant hemophagocytic lymphohistiocytosis (P = 0.040). Pseudo-progression was observed in three patients (10 %). The most common grade >= 3 toxicities were lymphopenia (25 %) and anemia (15.6 %). Conclusions: Tisle-GemOx exhibits promising anti-tumor activity and manageable toxicities as a salvage therapy for ENKTCL failing asparaginase. Further long-term follow-up is necessary to evaluate the durability of the response with tislelizumab maintenance in this patient population.