Durvalumab vs Placebo With Stereotactic Body Radiation Therapy in Early Stage Unresected Non-small Cell Lung Cancer (NSCLC) Patients / Osimertinib Following SBRT in Patients With Early Stage Unresected NSCLC Harboring an EGFR Mutation

Patients who are to receive SoC SBRT as definitive treatment of Stage I/II lymph node-negative NSCLC and confirmed to meet all eligibility criteria will be randomized 1:1 to Durvalumab or placebo. The primary objective of main cohort is to assess the efficacy of Durvalumab with SoC SBRT compared to placebo with SoC SBRT in terms of PFS. Key secondary is to assess the efficacy of Durvalumab with SoC SBRT compared to placebo with SoC SBRT in terms of Overall Survival (OS). In addition, a study cohort with a sufficient number of patients harboring an EGFR mutation, will receive Osimertinib treatment after completion of SoC SBRT as definitive treatment of Stage I/II lymph node-negative NSCLC. The primary objective of Osimertinib cohort is to assess efficacy of Osimertinib following SoC SBRT in terms of 4years-PFS. Key secondary objectives include safety, OS and efficacy of Osimertininb treatment with SBRT.