Neoadjuvant sintilimab and chemotherapy in patients with resectable esophageal squamous cell carcinoma: A prospective, single-arm, phase 2 trial

BACKGROUND: Immunotherapy (Programmed cell death 1 blockade) has entered the ranks of advanced esophageal cancer first-line treatment; however, little is known about the efficacy of PD-1 inhibitor as neoadjuvant therapy in resectable esophageal squamous cell carcinoma (ESCC). We aim to evaluate the activity and safety of the neoadjuvant sintilimab combined with chemotherapy in the treatment of resectable thoracic ESCC. METHODS: The enrolled patients with resectable (clinical stage II to IVA) ESCC received neoadjuvant sintilimab injection (200 mg/time, day 1), paclitaxel liposomes (135 mg/m(2), day 1), and carboplatin (area under curve of 5 mg/mL/min, day 1) every 21 days for 2 cycles, and esophagectomy was performed within 3-6 weeks after the 2 cycles of treatment. The primary endpoint of the study was the pathological complete response (PCR) rate. RESULTS: From July 2019 to March 2021, a total of 47 patients were enrolled, of which 33 patients (70.2%) had clinical stage III disease. All patients completed the full two-cycle treatment and forty-five patients received radical surgery, including 44 (97.8%) R0 resections. Ten (22.2%) of 45 patients had a PCR, and the major pathological response (MPR) rate was 44.4% (20/45). The grade 3–4 treatment-related adverse events (TRAEs) were mainly neutropenia (6 of 47,12.8%) and leucopenia (8 of 47,17.0%). One (2.1%) patient occurred postoperative immune-associated encephalitis. No delays in surgery were observed. CONCLUSIONS: sintilimab combined with paclitaxel liposome and carboplatin, as demonstrated in this phase II trial to exhibit a relatively high PCR rate and acceptable safety, warrants additional investigation in resectable ESCC. TRIAL REGISTRATION: http://www.chictr.org.cn/, ChiCTR1900026593.