Durvalumab has proven effective as a maintenance therapy following chemoradiotherapy in clinical trials for stage III non-small cell lung cancer (NSCLC), yet its impact in everyday clinical practice remains unclear. We conducted a multi-center observational study of veterans with stage III NSCLC to assess survival outcomes in those receiving durvalumab after chemoradiotherapy compared with patients treated with chemoradiotherapy alone. Survival analyses were performed using Kaplan–Meier estimates and Cox regression models, and outcomes were compared to PACIFIC trial results using an efficacy-effectiveness metric. The study included 1006 patients treated with durvalumab from 2017 to 2021 and 989 patients treated with chemoradiotherapy alone from 2015 to 2016. Durvalumab therapy was linked to improved progression-free survival (HR 0.62, 95% CI 0.55–0.70) and overall survival (HR 0.57, 95% CI 0.50–0.66). Despite these gains, overall survival in the veteran cohort was lower than in the PACIFIC trial population (HR 1.24, 95% CI 1.03–1.48; EE gap 0.73). These findings demonstrate that durvalumab provides meaningful survival benefits in real-world practice, though outcomes fall short of those reported in controlled clinical trials.
