Osimertinib is used to help prevent a certain type of non small-cell lung cancer (NSCLC) from returning after the tumor(s) has been removed by surgery in adults. It is also used as a first treatment for a certain type of NSCLC that has spread to other parts of the body in adults. Osimertinib is also used to treat certain types of NSCLC that has spread to other parts of the body in adults who could not be treated successfully with other similar chemotherapy medications. Osimertinib is in a class of medications called kinase inhibitors. It works by blocking the action of the abnormal protein that signals cancer cells to multiply. This helps stop or slow the spread of cancer cells and may help shrin. Osimertinib, sold under the brand name Tagrisso, is a medication used to treat non-small-cell lung carcinomas with specific mutations. It is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor.
The most common side effects include diarrhea, rash, musculoskeletal pain, dry skin, skin inflammation around nails, sore mouth, fatigue and cough. 
 Osimertinib was approved for medical use in the United States in November 2015,[7] and in the European Union in February 2016
 k tumors.