Toripalimab plus intensity-modulated radiotherapy for recurrent nasopharyngeal carcinoma: An open-label single-arm, phase II trial.

Abstract

6023 Background: Toripalimab is a humanized immunoglobulin G4 monoclonal antibody against programmed death 1 (PD-1). We aimed to investigate the efficacy and safety of toripalimab in combination with intensity-modulated radiotherapy (IMRT) for recurrent nasopharyngeal carcinoma (rNPC). Methods: We conducted a single-arm, phase II trial with rNPC patients who had biopsy-proven disease and were unsuitable for local surgery. Eligible patients received IMRT in combination with toripalimab administered via intravenous infusion of 240 mg once every 3 weeks for a maximum of seven cycles. The primary endpoint was the objective response rate (ORR). The secondary endpoints included safety profiles, progression-free survival (PFS). Results: Between May 2019 and January 2020, a total of 25 rNPC patients were enrolled (18 men [72.0%] and 7 women [28.0%]; median [IQR] age, 49.0 [43.5-52.5] years). With a median (IQR) follow-up duration of 14.6 months (13.1-16.2) months, 19 patients (79.2%) achieved an overall response, and disease control was achieved in 23 (95.8%) patients at 3 months post radiotherapy. The 12-month progression-free survival was 91.8% (95% CI 91.7% - 91.9%). The incidences of acute (grade ≥3) blood triglyceride elevation, creatine phosphokinase elevation, skin reaction, and mucositis were 1 (4.0%), 1 (4.0%), 2 (8.0%), and 1 (4.0%), respectively. The incidences of late severe (grade ≥3) nasopharyngeal wall necrosis, nasal bleeding, and trismus were 28.0%, 12.0%, and 4.0%, respectively. Conclusions: Toripalimab combined with IMRT was tolerable and showed promising antitumor activity in rNPC patients. Clinical trial information: NCT03854838.