Abstract
We evaluated the effectiveness of adding anti-PD-1 antibody to P-GEMOX regimen in previously untreated advanced-stage natural killer/T-cell lymphoma (NKTCL) compared to P-GEMOX alone or with autologous stem cell transplantation (ASCT). 418 patients (135 and 283 in the immunochemotherapy and chemotherapy groups, respectively) were analyzed from 15 Chinese centers (2014-2023). The median follow-up was 40.7 months. The immunochemotherapy group had a higher objective response rate (ORR) (89.6% versus 77.0%), complete response (CR) rate (77.0% versus 50.5%), 3-year progression-free survival (PFS) rate (64.1% versus 40.7%), and 3-year overall survival (OS) rate (79.5% versus 60.8%) compared to the chemotherapy group. Grade 3-4 neutropenia was more common in the immunochemotherapy group (40.0% versus 20.8% in the chemotherapy group, p < 0.001). Grade 3-4 hematologic toxicities were prevalent during ASCT, whereas anti-PD-1 maintenance was well tolerated. Grade ≥3 non-hematologic adverse events during anti-PD-1 maintenance were rare. In propensity score-matched (PSM) analysis of patients achieving CR after induction (n = 41 per group), the 3-year disease-free survival (DFS) rate was 72.6% for immunochemotherapy plus anti-PD-1 maintenance versus 50.9% for chemotherapy plus ASCT (p = 0.032), and the 3-year OS rate was 91.5% versus 72.9% (p = 0.029). First-line anti-PD-1 antibody plus P-GEMOX followed by anti-PD-1 maintenance shows better response and survival over P-GEMOX chemotherapy alone and P-GEMOX with ASCT, while maintaining acceptable toxicity.