Afatinib dimaleate is a medication primarily used in the treatment of metastatic non-small cell lung cancer (NSCLC) that harbors specific genetic mutations known as EGFR (epidermal growth factor receptor) mutations. It belongs to a class of drugs called tyrosine kinase inhibitors, which work by blocking the activity of certain proteins involved in cancer cell growth and spread. Afatinib is specifically indicated for patients with NSCLC whose tumors have EGFR mutations. It is typically taken orally in tablet form.