This study involves patients with non-small cell lung cancer that has spread to other parts of the body or grown locally in an advanced way and has a specific change in the cancer cells called an EGFR mutation. The treatment being studied is osimertinib, which is also known by its code name AZD9291, and is given as tablets taken by mouth. This medicine is already being used as a standard treatment for this type of lung cancer.
The purpose of this study is to find out if taking osimertinib less often than the usual daily dose works just as well as taking it every day. Patients in this study will already have been taking osimertinib once daily for at least three months and will have shown a positive response to the treatment, meaning their cancer has gotten smaller or stayed stable. The study will compare how well the cancer stays under control when patients continue taking the medicine every day versus taking it less frequently.
During the study, patients will continue their treatment with osimertinib and will be monitored regularly to see how the cancer responds and to check for any side effects. The study will also look at how the treatment affects patients’ daily lives and overall well-being, as well as the costs associated with different dosing schedules. Patients will be asked to complete questionnaires about their symptoms and quality of life throughout the study period, which is expected to last up to two years for each participant.
Belgium 
The Netherlands 
