Adjuvant durvalumab for esophageal squamous cell carcinoma after neoadjuvant chemoradiotherapy: a placebo-controlled, randomized, double-blind, phase II study

•The adjuvant durvalumab therapy failed to demonstrate the survival benefit in ESCC who underwent neoadjuvant CCRT.•This is the first report on the role of adjuvant immunotherapy in both pathologic complete response (ypCR) and non-ypCR.•The post-CCRT PD-L1 expression seems more useful than pre-CCRT PD-L1 expression in predicting the survival.•The benefit of adjuvant durvalumab seems to be greater in patients without ypCR than in those with ypCR. BackgroundWe evaluated the efficacy of adjuvant durvalumab after neoadjuvant concurrent chemoradiotherapy (CCRT) in patients with esophageal squamous cell carcinoma (ESCC).Patients and methodsThis randomized, double-blind, phase II study included patients with ESCC who underwent curative surgery after neoadjuvant CCRT. Patients were randomized to receive either durvalumab (20 mg/kg/i.v. every 4 weeks for 12 months) or placebo in a 1:1 ratio and were stratified by age and pathologic tumor stage. The primary endpoint was disease-free survival (DFS).ResultsBetween March 2016 and June 2018, 86 patients were randomized to the durvalumab (n = 45) or placebo (n = 41) arm. The median follow-up duration was 38.7 months. There was no difference in DFS hazard ratio (HR) 1.18, 95% confidence interval (CI) 0.62-2.27, P = 0.61 or overall survival (HR 1.08, 95% CI 0.52-2.24, P = 0.85) between the two arms. Subgroup analysis was performed for patients for whom the post-CCRT programmed death-ligand 1 (PD-L1) expression profile could be assessed (n = 54). In the PD-L1-positive group, based on tumor proportion score ≥1%, durvalumab was associated with longer overall survival compared with the placebo (36-month survival rate: 94% versus 64%; HR 0.42, 95% CI 0.10-1.76), while in the PD-L1-negative group, it was associated with shorter overall survival (42% versus 55%; HR 1.53, 95% CI 0.48-4.83), showing the tendency of interaction between post-CCRT PD-L1 status and adjuvant durvalumab therapy for overall survival (interaction P = 0.18).ConclusionsWe failed to demonstrate that adjuvant durvalumab improved survival after neoadjuvant CCRT in patients with ESCC. However, post-CCRT PD-L1 expression could predict the survival of patients who receive adjuvant durvalumab after neoadjuvant CCRT, which needs to be validated. We evaluated the efficacy of adjuvant durvalumab after neoadjuvant concurrent chemoradiotherapy (CCRT) in patients with esophageal squamous cell carcinoma (ESCC). This randomized, double-blind, phase II study included patients with ESCC who underwent curative surgery after neoadjuvant CCRT. Patients were randomized to receive either durvalumab (20 mg/kg/i.v. every 4 weeks for 12 months) or placebo in a 1:1 ratio and were stratified by age and pathologic tumor stage. The primary endpoint was disease-free survival (DFS). Between March 2016 and June 2018, 86 patients were randomized to the durvalumab (n = 45) or placebo (n = 41) arm. The median follow-up duration was 38.7 months. There was no difference in DFS hazard ratio (HR) 1.18, 95% confidence interval (CI) 0.62-2.27, P = 0.61 or overall survival (HR 1.08, 95% CI 0.52-2.24, P = 0.85) between the two arms. Subgroup analysis was performed for patients for whom the post-CCRT programmed death-ligand 1 (PD-L1) expression profile could be assessed (n = 54). In the PD-L1-positive group, based on tumor proportion score ≥1%, durvalumab was associated with longer overall survival compared with the placebo (36-month survival rate: 94% versus 64%; HR 0.42, 95% CI 0.10-1.76), while in the PD-L1-negative group, it was associated with shorter overall survival (42% versus 55%; HR 1.53, 95% CI 0.48-4.83), showing the tendency of interaction between post-CCRT PD-L1 status and adjuvant durvalumab therapy for overall survival (interaction P = 0.18). We failed to demonstrate that adjuvant durvalumab improved survival after neoadjuvant CCRT in patients with ESCC. However, post-CCRT PD-L1 expression could predict the survival of patients who receive adjuvant durvalumab after neoadjuvant CCRT, which needs to be validated.