Cancer Clinical Research Unit

INCLUSION CRITERIA: - Participant must be ≥ 18 years at the time of screening. - Histologically- or cytologically-documented NSCLC and have been treated with concurrent CRT for locally advanced, unresectable (Stage III) disease - Provision of a tumour tissue sample obtained prior to CRT - Documented tumour PD-L1 status by central lab - Documented EGFR and ALK wild-type status (local or central). - Patients must not have progressed following definitive, platinum based, concurrent chemoradiotherapy - Participants must have received at least 2 cycles of platinum-based chemotherapy concurrent with radiation therapy - Participants must have received a total dose of radiation of 60 Gy ±10% (54 Gy to 66 Gy) as part of the chemoradiation therapy, to be randomised. Radiation therapy should be administered by intensity modulated RT (preferred) or 3D-conforming technique. - WHO performance status of 0 or 1 at randomization - Adequate organ and marrow function EXCLUSION CRITERIA: - History of another primary malignancy except for malignancy treated with curative intent with no known active disease ≥5 years before the first dose of study intervention and of low potential risk for recurrence, adequately resected non-melanoma skin cancer and curatively treated in situ disease, or adequately treated carcinoma in situ or Ta tumours without evidence of disease. - Mixed small cell and non-small cell lung cancer histology. - Participants who receive sequential (not inclusive of induction) chemoradiation therapy for locally advanced (Stage III) unresectable NSCLC. - Participants with locally advanced (Stage III) unresectable NSCLC who have progressed during platinum-based cCRT. - Any unresolved toxicity CTCAE >Grade 2 from the prior chemoradiation therapy (excluding alopecia). - Participants with ≥grade 2 pneumonitis from prior chemoradiation therapy. - History of idiopathic pulmonary fibrosis, drug-induced pneumonitis, or idiopathic pneumonitis - regardless of time of onset prior to randomisation. Evidence of active non-CRT induced pneumonitis (≥ Grade 2), active pneumonia, active ILD, active or recently treated pleural effusion, or current pulmonary fibrosis - diagnosed in the past 6 months prior to randomization. - Active or prior documented autoimmune or inflammatory disorders (with exceptions) - Current or prior use of immunosuppressive medication within 14 days before the first dose of durvalumab.