Durvalumab and tremelimumab with definitive chemoradiotherapy for locally advanced esophageal squamous cell carcinoma

Background The current standard treatment for patients with inoperable, locally advanced esophageal squamous cell carcinoma (ESCC) is definitive concurrent chemoradiotherapy (CCRT). Methods Patients with locally advanced ESCC received 2 cycles of 5‐fluorouracil, cisplatin, durvalumab, and tremelimumab every 3 weeks with concurrent radiation therapy (60.2 or 64.5 grays). After completing CCRT plus immunotherapy, patients received 2 cycles of consolidative durvalumab and tremelimumab followed by durvalumab monotherapy every 4 weeks for 2 years after enrollment. Their survival outcomes were compared with those from a propensity score‐matched historical control group that had received CCRT alone. Results In total, 40 patients were enrolled and analyzed. The 24‐month progression‐free survival (PFS) and overall survival rates were 57.5% and 75%, respectively. Compared with the historical control group (n = 75), the study population had significantly longer PFS (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.28‐0.97; P = .040) and overall survival (HR, 0.49; 95% CI, 0.25‐0.98; P = .043). In the study population, patients who had PD‐L1–positive tumors (n = 28) had significantly longer PFS (HR, 0.20; 95% CI, 0.07‐0.54; P < .001) and overall survival (HR, 0.16; 95% CI, 0.05‐0.56; P = .001) compared with those who had PD‐L1–negative tumors (n = 11). However, there was no difference in survival outcomes according to PD‐L1 status in the historical control group, indicating a strong interaction between PD‐L1–positive status and survival outcomes in the treatment groups (PFS, P for interaction = .003; overall survival, P for interaction = .002). Conclusions Durvalumab and tremelimumab with definitive CCRT had promising efficacy in patients with locally advanced ESCC. In addition, PD‐L1 expression had strong predictive value in the study population.