Observational Study of Afatinib 30 mg Daily

Afatinib, a first-in-class irreversible ErbB family blocker, is a 1st line treatment option for patients with advanced stage NSCLC harbouring sensitizing EGFR mutations. In randomized 1st line studies of afatinib at a standard dose of 40 mg daily versus standard of care, 28-53% of patients required a dose reduction due to adverse events (AE) induced by afatinib. The most common AEs are cutaneous and gastrointestinal (diarrhoea, dysphagia, and mucositis). Prevalence of diarrhoea in patients receiving 40 mg of afatinib, in 1st line phase II and III studies is as high as 90.0% (all grades of diarrhoea) and 14.4% (grade 3-4 diarrhoea). Another important gastrointestinal AE is mucositis, which presents in 51.9%-64.4% of patients treated with afatinib, with only 4.4%-8.3% of the cases being grade 3-4. Dose reduction tended to occur in patients who had higher initial afatinib plasma concentrations and led to decreases in the incidence and severity of afatinib-related AEs without affecting therapeutic efficacy. The incidence of gastrointestinal AEs could be decreased \>50% with proper afatinib dose reduction. The effect of 1st line afatinib 30 mg daily in patients with EGFR mutation-positive NSCLC is unknown. We hypothesize that, in patients with EGFR mutation-positive NSCLC, 1st line afatinib treatment at 30 mg daily is tolerable with less gastrointestinal AEs and with a similar efficacy to standard dose afatinib.