Toripalimab plus gemcitabine and cisplatin induction chemotherapy in locoregionally advanced nasopharyngeal carcinoma: a retrospective study.

Objective: To explore the efficacy and safety of toripalimab combined with gemcitabine and cisplatin (GP) induction chemotherapy and sequential concurrent chemoradiotherapy in LANPC treatment. Methods: This was a retrospective analysis of 105 patients with LANPC from December 2019 to December 2022. In total, 50 patients received two or three cycles of GP induction chemotherapy and 55 patients received toripalimab plus GP. Toripalimab (240 mg) was given intravenously on the first day of each cycle of induction chemotherapy. All patients received radiotherapy or concurrent chemoradiotherapy with cisplatin. Results: After induction therapy, 17 (30.9%) patients in the GP plus toripalimab group and 6 (12.0%) in the GP alone group achieved complete response (CR) (p=0.019). After a median follow-up of 38.6 months, 16.0% (8/50) of the patients in the GP group and 3.6% (2/55) of the patients in the toripalimab plus GP group experienced recurrence or metastasis. There were 2 deaths in the GP group and no deaths in the toripalimab plus GP group. The 2-year event-free survival (EFS) rate was higher in the toripalimab plus GP group than in the GP group (98.1% vs. 85.4% (HR, 0.28; 95% confidence interval [CI], 0.08-0.97; p=0.024)). The 2-year overall survival, locoregional relapse-free survival and distant metastasis-free survival rates for toripalimab plus GP vs. GP alone were 100.0% vs. 100.0% (p=1.00), 98.1% vs. 89.5% (p=0.086), and 100.0% vs. 95.9% (p=0.15), respectively. Grade 3-4 adverse events (AEs) occurred in 26 (47.3%) and 29 (58.0%) patients in the toripalimab plus GP and GP alone arms, respectively. The most common grade 3-4 AEs were neutropenia (20 [36.4%] vs. 21 [42.0%]), leukopenia (18 [32.7%] vs. 17 [34.0%]), and vomiting (15 [27.3%] vs. 12 [24.0%]) in the toripalimab plus GP arm compared with the GP alone arm. Immune-related AEs of grade 3-4 occurred in three (5.5%) patients in the toripalimab plus GP arm. Conclusions: The addition of toripalimab to GP induction chemotherapy significantly improves EFS without increasing toxicity in LANPC.