A Study Osimertinib in Patients With Stage 4 Non-small Cell Lung Cancer With Uncommon EGFR Mutations

This is a research study to find out if a drug called, osimertinib, is safe and effective in treating advanced Non-Small Cell Lung Cancer (NSCLC) by targeting the treatment of epidermal growth factor receptor (EGFR) mutation exon 18 G719X, exon 20 S7681, or exon 21 L861Q. Patients on the study will not have had previous tyrosine kinase inhibitor (TKI) treatment. Patients who have one of the following EGRF mutations: exon 18 G719X, exon 20 S7681, or exon 21 L861Q) may be eligible to participate in this study. If enrolled into the study, the study team will give the patient a supply of the study drug, osimbertinib (80 mg) to take at home. The patient will be asked to take the study drug by mouth on days 1-28 of each study cycle. As part of this study, the patient will have blood samples other tests, exams and procedures done for study purposes and their standard of care. Patient participation in the study will last for up to 2 years after completion of the last dose of the study drug or until your condition worsens or intolerable adverse events as deemed by the study doctor. There are possible patient risks to this study that include but are not limited to diarrhea, changes to the lining of the mouth (e.g. ulcers), rash, dry skin, itching, and nail infections.