Neoadjuvant and adjuvant toripalimab for locoregionally advanced nasopharyngeal carcinoma: a randomised, single-centre, double-blind, placebo-controlled, phase 2 trial

Abstract

Patients with locoregionally advanced nasopharyngeal carcinoma with a high pretreatment plasma concentration of Epstein-Barr virus (EBV) DNA remain at high risk for recurrence after concurrent chemoradiotherapy. This study aimed to compare the efficacy and safety of neoadjuvant-adjuvant treatment with the PD-1 inhibitor toripalimab and concurrent chemoradiotherapy versus placebo and concurrent chemoradiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma. This randomised, single-centre, double-blind, placebo-controlled, phase 2 trial was conducted at Sun Yat-sen University Cancer Centre in Guangzhou, China. Adult patients (aged 18-65 years) with newly diagnosed high-risk stage III-IVa locoregionally advanced nasopharyngeal carcinoma, with a pretreatment plasma EBV DNA concentration of at least 1500 copies per mL and an Eastern Cooperative Oncology Group performance score of 0-1, were eligible. Patients were randomly assigned (2:1) using an interactive web response system (block size of six), stratified by TNM stage (III vs IVa), to neoadjuvant toripalimab (240 mg intravenously) or placebo once every 2 weeks for two cycles, followed by concurrent cisplatin (100 mg/m2 intravenously) on days 1, 22, and 43 during intensity-modulated radiotherapy and adjuvant toripalimab (240 mg intravenously) or placebo once every 3 weeks for up to eight cycles. The primary endpoint was 2-year progression-free survival in the intention-to-treat population. This study was registered with ClinicalTrials.gov, NCT03925090, and is closed to enrolment; follow-up is ongoing. Between Dec 6, 2019, and Dec 9, 2021, 150 patients were enrolled and randomly assigned to the toripalimab group (n=100) or placebo group (n=50). 115 (77%) patients were male and 35 (23%) were female. As of data cutoff (May 31, 2024), median follow-up for progression-free survival was 37·8 months (IQR 34·2-46·5) for the intention-to-treat population analyses. 2-year progression-free survival was higher in the toripalimab group (92·0% [95% CI 86·7-97·3]) than in the placebo group (74·0% [61·8-86·2]; stratified hazard ratio 0·40 [95% CI 0·18-0·89]; log-rank p=0·019). The most common grade 3 or worse acute adverse events (occurring within 1 year of randomisation) were leukopenia (40 [40%] of 99 patients in the toripalimab group vs 22 [44%] of 50 patients in the placebo group), mucositis (28 [28%] vs ten [20%]), neutropenia (17 [17%] vs nine [18%]), anaemia (16 [16%] vs five [10%]), and weight loss (12 [12%] vs six [12%]). The most common grade 3 or worse late adverse events (occurring >1 year after randomisation) was auditory or hearing loss (eight [8%] vs four [8%]). Immune-mediated adverse events of grade 3 or worse occurred in ten (10%) patients only in the toripalimab group. One (2%) of 50 patients in the placebo group died due to septic shock caused by bacteraemia considered not treatment related. There were no treatment-related deaths in the toripalimab group. Our findings suggested that a so-called sandwich approach involving toripalimab (in the neoadjuvant and adjuvant phases) combined with concurrent chemoradiotherapy could be a highly promising therapy for the treatment of locoregionally advanced nasopharyngeal carcinoma. Phase 3 non-inferiority trials are warranted comparing neoadjuvant and adjuvant toripalimab versus cisplatin plus gemcitabine neoadjuvant chemotherapy combined with concurrent chemoradiotherapy. National Key Research and Development Program of China, National Natural Science Foundation of China, Guangdong Basic and Applied Basic Research Foundation, Science and Technology Program of Guangzhou, Sun Yat-sen University Clinical Research 5010 Program, Innovative Research Team of High-level Local Universities in Shanghai, Postdoctoral Innovative Talent Support Program, Planned Science and Technology Project of Guangdong Province, Key Youth Teacher Cultivating Program of Sun Yat-sen University, and Fundamental Research Funds for the Central Universities. For the Chinese translation of the abstract see Supplementary Materials section.