Neoadjuvant sintilimab plus chemotherapy for locally advanced resectable esophageal squamous cell carcinoma: a prospective, single-arm, phase II clinical trial (CY-NICE).

Background: Adding immune checkpoint inhibitors (ICIs) to the chemotherapy has shown significant clinical benefits in neoadjuvant treatment of locally advanced esophageal squamous cell carcinoma (ESCC). Sintilimab is one such ICI used for treatment. Herein, we designed a trial to evaluate the safety and efficacy of sintilimab combined with paclitaxel and platinum for locally advanced resectable ESCC.

Methods: Patients with locally advanced resectable (stage II-III) ESCC were enrolled and received at least two cycles of neoadjuvant therapy with sintilimab (200 mg on day 1) plus platinum-based chemotherapy in each 3-week cycle followed by esophagectomy. The primary endpoint of the trial was the pathological complete response (pCR) rate. The secondary endpoints were the major pathological response (MPR) rate, the objective response rate (ORR), the treatment-related adverse events (TRAEs), the immune-related adverse events (irAEs) and quality of life (QOL). Besides, relapse-free survival (RFS), overall survival (OS) were exploratory endpoints. Forty-three cases were needed to be enrolled in this trial. It was assumed the regimen of the neoadjuvant sintilimab plus chemotherapy would achieve a pCR rate of 30.5%.

Results: Between March 2021 and January 2023, a total of 43 patients (41 men and 2 women) were enrolled, including 11 cases (25.6%) of clinical stage II and 32 cases (74.4%) of clinical stage III at baseline. All the 43 patients completed two cycles of neoadjuvant therapy, and 32 patients received McKeown radical resection for esophageal cancer. The pCR rate was 28.1% (9/32), which was below the 30.5% reference cutoff value, and the MPR rate was 37.5% (12/32). According to RECIST 1.1, four patients (4/43, 9.3%) had a complete response (CR), 21 patients (21/43, 48.8%) had a partial response (PR), ORR was 58.1% (25/43). The incidence of ≥ grade 3 TRAEs was 23.3% (10/43) and there were no ≥ grade 4 TRAEs.

Conclusions: Sintilimab plus platinum-based chemotherapy as neoadjuvant therapy is safe, feasible and effective in locally advanced resectable ESCC, suggesting a supportive rationale for its further evaluation in randomized clinical trials.

Trial Registration: Chinese Clinical Trial Registry identifier: ChiCTR2200056558.