Osimertinib Alone or With Chemotherapy for EGFR-Mutant Lung Cancers

This study will compare the effectiveness of osimertinib alone with the combination of osimertinib and chemotherapy (carboplatin and pemetrexed) in people with metastatic lung cancer that has a change (mutation) in the gene EGFR. Osimertinib alone is the usual treatment for metastatic EGFR-mutant lung cancer. Researchers think adding chemotherapy to osimertinib could possibly add to the anticancer effects of the usual treatment and help stop cancer from growing or spreading.