RecruitingPhase 3Drug trialA Clinical Study to Assess the Efficacy of Adjuvant Immunotherapy With Cemiplimab in Patients With Surgically Removed Non-small Cell Lung Cancer Who Have Not Received Prior ChemotherapyARCH is a randomised, stratified, multicentre, phase III trial. Protocol treatment consists of cemiplimab, 350 mg i.v., every 3 weeks, for 4 cycles, followed by 700 mg i.v., every 6 weeks for 6 cycles or until relapse or unacceptable toxicities, whichever occurs first. The primary objective of the study is to determine the efficacy of adjuvant cemiplimab, as measured by disease-free survival, in patients without prior adjuvant platinum-based chemotherapy, compared to observation without adjuvant treatment. The primary objective will be assessed in patients with tumours with centrally confirmed PD-L1 expression of ≥1%.