Gilotrif, also known as afatinib, is now approved to treat patients with metastatic non-small cell lung cancer (NSCLC) that have an EGFR gene mutation. The drug was approved quickly by the Food and Drug Administration under the agency's priority review program because of the aggressive nature of NSCLC, and the fact that there are few treatment options for patients with this type of cancer. [FDA: FDA approves new treatment for a type of late-stage lung cancer]NSCLC is the most common type of lung cancer, but EGFR mutation-positive lung cancers account for about 10 percent, which still means that thousands of patients may potentially benefit from the new drug. In addition to the drug approval, the FDA also approved a diagnostic test that identifies lung cancers with the EGFR mutation. The practice of approving therapies with a specific diagnostic test is something we may be seeing more of in the future. Tarceva (erlotinib), a lung cancer drug that also targets the EGFR mutation, was approved in May to treat patients with newly diagnosed NSCLC, along with a separate EGFR test. (Tarceva was previously approved for second-line NSCLC and as maintenance therapy.) "Companion diagnostics are a fundamental element of personalized treatment for cancer and other diseases," said Tadd Lazarus, chief medical officer of Qiagen, the company that developed Gilotrif's companion diagnostic test, in response to an email question. "Diagnostics such as therascreen EGFR can identify patients who are most likely to respond to treatment and avoid ineffective, expensive and potentially harmful medical care." Lazarus added that "Within the next five to 10 years, all new oncology drugs will have a companion diagnostic," according to a report from Tufts University in Boston. The drug, which is taken orally, was approved based on a large-scale phase 3 clinical study called LUX Lung-3, which compared Gilotrif with (Alimta) pemetrexed and cisplatin. Of the 345 participants, those who received Gilotrif delayed cancer growth a median of 4.2 months (11.1 months versus 6.9 months). In a group of participants who had the most common types of EGFR mutations, such as exon 19 deletion, the delay in progression was nearly double with Gilotrif (13.6 versus 6.9 months). Reports also show that quality of life was better in the investigational arm. A benefit in overall survival was not seen, but participants in the chemotherapy arm may have received another EGFR-targeted therapy after their disease progressed. Results were announced last year at the annual meeting of the American Society of Clinical Oncology (ASCO) [CURE: Afatinib Helps Delay Lung Cancer Progression].Studies do suggest that Gilotrif blocks the EGFR pathway for a longer period of time than Tarceva. The drug also inhibits the HER2 pathway, a mutation that is sometimes seen in breast and gastric cancers. The next step may be to compare Gilotrif with the other EGFR-targeted therapies, Tarceva and Iressa (gefitinib). The LUX-Lung 7 trial will compare Gilotrif to Iressa. Side effects of Gilotrif include diarrhea, skin issues, inflammation in the mouth, throat or lung, and liver toxicity. For more information on EGFR mutation-positive lung cancer, Cancer.Net (ASCO's patient website) explains the importance of testing for the EGFR mutation and what it means for treatment options. Afatinib is also being examined in head and neck cancers, gliomas and other solid tumors.