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

Abstract

Background: 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.

Methods: 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.

Findings: 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.

Interpretation: 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.

Funding: 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.

Translation: For the Chinese translation of the abstract see Supplementary Materials section.