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.