Background: Consolidation durvalumab is approved for treatment of newly diagnosed, unresectable stage III non-small cell lung cancer (NSCLC) who have not progressed after definitive chemoradiotherapy (CRT) and the NCCN guidelines has since included stage II NSCLC who have not progressed after definitive CRT. Methods: A retrospective, observational real-world study was conducted to identify and describe the off-label use of consolidation durvalumab in NSCLC after completion of CRT between June 2018-June 2021. Data sources included claims data and electronic medical records submitted with prior authorization (PA) requests to OncoHealth, a digital health company that reviews PA requests for cancer treatment. With a data cut-off of 12/22/2022, real-world Time to Progression (rwTTP) and real-world Time to Next Treatment (rwTTNT) were evaluated. All endpoints were measured from the start of consolidation durvalumab treatment; rwTTP spanned until earliest date of clinician-reported progression and rwTTNT spanned until initiation of subsequent treatment. Results: Among 326 patients identified to have received durvalumab after definitive CRT, 45 (13.8%) received off-label treatment. The median age was 71 years (range: 53 to 88), 51% male, 53% former smokers, 29% Stage I, IIA or IIB, 71% locoregional recurrent disease; 58% squamous histology, 47% had undergone prior surgery +/- adjuvant chemo, 27% received prior radiation only and 98% received concomitant platinum-based chemotherapy prior to durvalumab. Median time to initiating durvalumab after CRT was 47 days. After a median follow up of 13.1 (range: 7.0-50.7) months, 33% (n = 15) had progression of disease. The median rwTTP was 14.0 (range: 4.2-32.9) months and median rwTTNT was 14.7 (range: 6.0-33.0) months. Conclusions: In the real world, off-label use of consolidation durvalumab was based on clinical justification and extrapolation of results from PACIFIC trial. The results of rwTTP and rwTTNT outcomes suggest patients with early stage or recurrent disease achieved clinically meaningful benefit from treatment approach used in the PACIFIC trial. With additional patients and longer follow up, real-world data could shed light on the appropriateness of expanding off-label use of durvalumab consolidation.