The efficacy of 40 mg versus dose de-escalation to less than 40 mg of afatinib (Giotrif) as the first-line therapy for patients with primary lung adenocarcinoma harboring favorable epidermal growth factor mutations.

The choice of a first-line therapy for lung cancer is a crucial decision that can impact the survival as well as the quality of life of a patient. Inhibitors of epidermal growth factor receptor (EGFR) such as afatinib, erlotinib, and gefitinib have previously been used to treat non-small cell lung cancer harboring favorable EGFR mutations. Although afatinib has greater efficacy than other EGFR inhibitors, adverse events related to its use can result in the discontinuation of the therapy. In this study, we compared the therapeutic efficacy in lung cancer patients of a regimen of 40 mg/day of afatinib with that of a lower dose regimen of <40 mg/day resulting either from a lower starting dose of 30 mg/day or dose adjustment. Seventy-nine patients were treated with 40 mg/day and 67 received de-escalated doses of <40 mg/day. There was no significant difference in the clinical characteristics of the two groups except that the proportion of patients with a body weight of 50 kg or more was greater in the 40 mg/day group. Otherwise, there were no significant differences between the two groups in the average time to treatment failure (TTF), the rates at which the administration of a second-line therapy was necessary, or the frequency and severity of adverse events. Overall, these results suggest that it is possible to calibrate the dosage of afatinib to suit individual patient parameters such as low body weight, and that such calibration can be advised based on the given patient's individual experience of the drug.