The dimaleate salt form of afatinib, an orally bioavailable anilino-quinazoline derivative and inhibitor of the receptor tyrosine kinase (RTK) epidermal growth factor receptor (ErbB; EGFR) family, with antineoplastic activity. Upon administration, afatinib selectively and irreversibly binds to and inhibits the epidermal growth factor receptors 1 (ErbB1; EGFR), 2 (ErbB2; HER2), and 4 (ErbB4; HER4), and certain EGFR mutants, including those caused by EGFR exon 19 deletion mutations or exon 21 (L858R) mutations. This may result in the inhibition of tumor growth and angiogenesis in tumor cells overexpressing these RTKs. Additionally, afatinib inhibits the EGFR T790M gatekeeper mutation which is resistant to treatment with first-generation EGFR inhibitors. EGFR, HER2 and HER4 are RTKs that belong to the EGFR superfamily; they play major roles in both tumor cell proliferation and tumor vascularization and are overexpressed in many cancer cell types. or A drug used to treat non-small cell lung cancer that has spread to other parts of the body. It is used in patients with certain mutations (changes) in a cell protein called epidermal growth factor receptor (EGFR). It is also being studied in the treatment of other types of cancer. Afatinib dimaleate blocks certain EGFRs, which may help keep cancer cells from growing. It may also prevent the growth of new blood vessels that tumors need to grow. Afatinib dimaleate is a type of tyrosine kinase inhibitor and a type of antiangiogenesis agent. Also called Gilotrif.