Phase Ib trial of camrelizumab combined with chemotherapy and apatinib for neoadjuvant treatment of locally advanced thoracic esophageal squamous cell carcinoma

Abstract

This is a prospective, single-arm, phase Ib study to evaluate the safety and efficacy of camrelizumab combined with chemotherapy and apatinib as neoadjuvant therapy for locally advanced thoracic esophageal squamous cell carcinoma (ESCC). The regimen encompassed 2-4 cycles of neoadjuvant camrelizumab, nab-paclitaxel, nedaplatin, and apatinib to treatment-naive patients with resectable locally advanced ESCC. The treatment was repeated every 14 days. Initially, six patients were planned to receive two cycles of neoadjuvant therapy as safety assessment, and then 24 patients received four cycles of neoadjuvant therapy, followed by esophagectomy after 4-8 weeks. The primary endpoint was safety. The key secondary endpoints were pathologic complete response (pCR) and major pathologic response (MPR). This study enrolled 30 patients, among whom, five patients received two cycles of neoadjuvant therapy, and one patient missed the second cycle of therapy due to grade 3 elevated alanine transaminase (ALT) level. The remaining 24 patients received four planned cycles of neoadjuvant therapy. Eleven patients (36.7%) developed grade 3 neoadjuvant treatment-related adverse events (TRAEs). No patient developed grade 4 or 5 TRAEs. Neutropenia (23.3%) was the most common grade 3 TRAE. Twenty-nine patients underwent esophagectomy after neoadjuvant therapy. Among them, 15 patients (51.7%) achieved MPR, including seven patients with pCR (24.1%). Radiographic analyses established a significant correlation between maximal standardized uptake value (SUVmax) reduction and pathologic regression (P=0.00095). Neoadjuvant camrelizumab combined with chemotherapy plus apatinib demonstrated a manageable safety profile for patients with locally advanced ESCC, and an encouraging efficacy was observed in most of the treated patients. A decrease in SUVmax of the primary tumor may be a predictor of pathologic response to neoadjuvant camrelizumab combined with chemotherapy plus apatinib in ESCC.