A Study to Investigate the Efficacy and Safety of Dato-DXd With or Without Osimertinib Compared With Platinum Based Doublet Chemotherapy in Participants With EGFR-Mutated Locally Advanced or Metastatic Non-Small Cell Lung Cancer

This is a Phase III, open-label, 3-arm, multicenter study assessing the effects of Dato-DXd in combination with osimertinib or Dato-DXd monotherapy versus platinum-based doublet chemotherapy in participants with epidermal growth factor receptor gene mutation (EGFRm) locally advanced or metastatic non-small cell lung cancer (NSCLC) whose disease has progressed on prior osimertinib treatment. Participants will be randomized in a 1:1:1 ratio to one of the following intervention groups: 1. Dato-DXd + osimertinib combination therapy 2. Dato-DXd monotherapy 3. Platinum-based doublet chemotherapy Participants will receive study intervention until Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1) -defined radiological progression by the investigator, unacceptable toxicity, or other discontinuation criterion is met. After study intervention discontinuation, all participants will undergo an end of treatment (EoT) visit within 35 days of discontinuation and will be followed up for safety assessments 28 (+ 7) days after their last dose of study intervention.