A phase II clinical trial of toripalimab combined with neoadjuvant chemoradiotherapy in locally advanced esophageal squamous cell carcinoma (NEOCRTEC1901).

Background: To evaluate the efficacy and safety of toripalimab combined with neoadjuvant chemoradiotherapy (NCRT) for locally advanced esophageal squamous cell carcinoma (ESCC). Methods: In this single arm, phase II trial, 44 ESCC patients were enrolled from December 2019 to July 2021 at Sun Yat-sen University Cancer Center (Guangzhou, China). All patients received concurrent radiotherapy (44 Gy in 20 fractions), chemotherapy (paclitaxel 50 mg/m2 and cisplatin 25 mg/m2 on days 1, 8, 15, and 22), and toripalimab (240 mg on days 1 and 22). Within 6-8 weeks of neoadjuvant treatment, patients underwent surgery. The results of the study patients were compared with those of 86 matched patients between July 2015 and March 2022. The primary endpoint was pathological complete response (pCR) rate, and the secondary endpoints were treatment-related adverse events and R0 rates. This trail was registered with ClinicalTrails.gov, NCT04006041. Findings: All patients received neoadjuvant treatment, and 42 completed esophagectomy. Of the 42 patients, 21 (50%; 95% CI 35-65) achieved pCR and 2 (5%) patients were ypT0N+. The R0 resection rate was 98% (41/42). Nine (20%) of 44 patients had grade 3/4 adverse events. Among the perioperative complications (n = 42), anastomotic leakage occurred in five cases (12%), tracheal fistula in three cases (7%), and postoperative death in one case (2%) due to tracheal fistula. Compared with the control cohort, the pCR rate of the study group was higher but without significant difference (50% vs. 36%, P = 0.19). Interpretation: Toripalimab combined with NCRT failed to show significantly better pCR rate than historical data. Nevertheless, considering the signs of efficacy and acceptable safety of this regimen, further evaluation in phase III randomized trials might be warranted. Funding: National Natural Science Foundation of China.