Abstract 416: Toripalimab plus paclitaxel and carboplatin as neoadjuvant therapy in patients with locally advanced resectable esophageal squamous carcinoma: An open-label, single arm phase 2 trial

Background: Immune checkpoint inhibitors (ICIs) have shown promising results in patients with advanced esophageal squamous carcinoma (ESCC), while their efficacy for locally advanced patients is unclear. We conducted a neoadjuvant immunotherapy trial, investigating the safety and feasibility of toripalimab, a PD-1 inhibitor, combined with paclitaxel and carboplatin in patients with resectable ESCC (ClinicalTrials.gov identifier: NCT04177797). Methods: Between May 2020 and June 2020, 18 patients with histopathologically diagnosed ESCC, clinically staged as T3N1-3M0, ECOG PS 0, received toripalimab 240 mg IV, D1, Q3W and paclitaxel 135 mg/m2, IV, D1, Q3W and carboplatin AUC 5 mg/mL per min, IV, D1, Q3W for two cycles, followed by McKeown esophagectomy 4-6 weeks later. The primary endpoint were safety and major pathological response (MPR) rate, and the secondary point were pathological complete response (pCR) rate, DFS and OS. Results: Sixteen patients received surgery with no treatment-related surgical delay, and the R0 resection rate was 87.5% (14/16). Two patients refused surgery due to the clinical assessment as complete response. Among 16 patients undergoing surgery, 3 (16.6%) were pCR and 7 (43.8%) were MPR. Treatment-related adverse events occurred in all patients (100%), and 4 patients (22.2%) experienced grade 3 or higher treatment-related adverse events including neutropenia (2, 12.5%), leukopenia (1, 6.2%), diarrhea (1, 6.2%), fatigue (1, 6.2%). No surgery-related adverse events or treatment-related death occurred. Conclusions: The combination of toripalimab, paclitaxel and carboplatin for patients with locally advanced resectable ESCC is well tolerated and shows antitumor activity, which might be a potential neoadjuvant therapy regimen. Citation Format: Wenwu He, Lin Peng, Yu Bao, Wenguang Xiao, Qiang Fang, Xuefeng Leng, Jiaxin Yan, Tianqin Mao, Xudong Shen, Depei Huang, Hushan Zhang, Xueke She, Yongtao Han. Toripalimab plus paclitaxel and carboplatin as neoadjuvant therapy in patients with locally advanced resectable esophageal squamous carcinoma: An open-label, single arm phase 2 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 416.