Neoadjuvant docetaxel-cisplatin followed by concurrent chemoradiotherapy and adjuvant tislelizumab for locally advanced nasopharyngeal carcinoma: A multicenter, single-arm, phase II trial.

Abstract

e18047 Background: Patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC) have a high risk of distant metastasis or recurrence despite the current standard of neoadjuvant chemotherapy and concurrent chemoradiation (CCRT), indicating the need of more comprehensive treatment. Due to good compliance and convenient adverse event management, the TP (docetaxel and cisplatin) regimen is more widely accepted and commonly used as a neoadjuvant chemotherapy for LA-NPC in the real world. Immune checkpoint blockade therapy plus chemotherapy has been shown to improve the survival in recurrent or metastatic NPC. We investigated the efficacy and safety of tislelizumab, an anti-PD-1 monoclonal antibody, as adjuvant treatment in patients with LA-NPC that had the neoadjuvant TP chemotherapy and CCRT. Methods: This multicenter, open label, single arm, phase II clinical trial was done at four hospitals in China. Patients (aged 18-65 years) with histologically confirmed, LA-NPC (T4N1 and T1-4N2-3) were enrolled and treated with neoadjuvant chemotherapy for 3 cycles (docetaxel 75 mg/m2 D1, cisplatin 75 mg/m2 D1) followed by concurrent cisplatin (100mg/m2, D1 and D22) during intensity-modulated radiation (IMRT). Four weeks post-RT, tislelizumab (200 mg) was given intravenously once every 3 weeks for up to 12 cycles. By Fleming one-stage design (type I error 0.05, power 0.80, 10% drop out), planned sample size is 100. Primary endpoint is 3-year (yr) progression free survival (PFS). Secondary endpoints include safety and tolerability. Results: From June 2021 to January 2024, a total of 100 patients (median age 53y, 73.0% male) were recruited at four study sites. This protocol specified analysis included 78 subjects with >12 months post-treatment follow up (median 26.2 months, 95% CI 21.3-30.1). Overall compliance rate: neoadjuvant cisplatin + docetaxel 97.5%, concurrent cisplatin 80.8%, adjuvant tislelizumab 78.2%, IMRT 99.7% (69.96 Gy). Treatment related adverse events (AEs, ≥grade 3, >10%): dysphagia (30.5%), mucositis (26.2%), neutropenia(26.7%), radiation dermatitis (23.7%), anemia (16.2%). No ≥grade 4 mucositis/dermatitis. In addition, the incidence of immune-related adverse events (irAEs) of grade 3 or 4 was 5.2%, and all were thyroid toxicity and skin rash. The 2-yr PFS and 2-yr overall survival were 89.6% (95% CI 53.8 - 88.5%) and 100%, respectively. 3-yr PFS and long-term efficacy are awaited. Conclusions: Tislelizumab adjuvant therapy after neoadjuvant docetaxel -cisplatin followed by CCRT is safe with promising results for LA-NPC. However, further follow-up is needed to confirm the long-term efficacy. Clinical trial information: NCT04870905 .