Observational Multicenter Study in Patients Receiving Chemotherapy and Amivantamab for Metastatic Non-small Cell Lung Cancer

The purpose of this observational study is to understand how well a treatment combining chemotherapy and amivantamab works in real life, and how safe it is, in adults with metastatic non-small cell lung cancer (NSCLC) who have certain EGFR gene mutations. The study includes two groups of people: * Group A: people with an EGFR exon 20 insertion who receive amivantamab together with platinum-based chemotherapy as their first treatment, through an early access program. * Group B: people with an EGFR exon 19 or exon 21 mutation who receive amivantamab with platinum-based chemotherapy after having been treated with osimertinib (with or without chemotherapy), also through an early access program. The main question the study wants to answer is: How long can the combination of amivantamab and chemotherapy keep the cancer from coming back or getting worse in these two groups of people? People already receiving amivantamab and chemotherapy for NSCLC through an early access program may be included. They will continue to be followed by their usual oncologist as part of their normal medical care. The study will simply collect their medical information from March 21, 2024 to October 21, 2025. No extra tests or procedures are required. This is an observational study, carried out by the GFPC and partner centers in France.