Induction chemotherapy plus camrelizumab followed by concurrent chemoradiotherapy in unresectable locally advanced esophageal squamous cell carcinoma: a single-arm phase II trial

Concurrent chemoradiotherapy (CCRT) has remained the standard treatment for unresectable locally advanced esophageal squamous cell carcinoma (ESCC), yet survival remains poor. This single-arm, phase II trial aims to evaluate the efficacy and safety of two cycles of induction chemotherapy with camrelizumab followed by CCRT in previously untreated patients with unresectable locally advanced ESCC. The primary endpoint, the 1-year overall survival (OS) rate in the per-protocol population (N = 46), was 87.0% (95% confidence interval [CI]: 77.7%-97.3%), exceeding the pre-specified target. Secondary endpoints included OS in the intention-to-treat (ITT) population, progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR), duration of response, safety, and health-related quality of life. In the ITT population (N = 49), the 1-year OS rate was 85.7% (95% CI: 76.5%-96.1%). The 1-year PFS rates in the per-protocol and ITT populations were 71.7% (95% CI: 59.8%-86.0%) and 71.4% (95% CI: 59.8%-85.3%), respectively. The median OS, PFS, and duration of response were not reached. Following CCRT, the ORR was 93.5%, with a DCR of 95.7%. Lymphopenia was the most frequent Grade ≥3 adverse event (100%). One patient died from treatment-related myelosuppression. Health-related quality of life generally improved after induction therapy, with significant improvements in global health status, emotional functioning, and some symptom relief, despite a slight decline in physical functioning. Here, we show that induction chemoimmunotherapy followed by CCRT exhibits promising efficacy and manageable safety in patients with unresectable locally advanced ESCC, thus warranting further randomized controlled trials. Trial number: ChiCTR2000034304.