Multi-institutional study of osimertinib dose-optimization in non-small cell lung cancer patients with EGFR activating mutation aged 70 years or older ('MONEY' trial).

Osimertinib is the standard of care for patients with epidermal growth factor receptor-activating mutation-positive non-small cell lung cancer. Dose-toxicity has been previously reported, but no dose-response data within the range of 20-240 mg daily (mg/d). Thus, the current 80 mg/d dosing might be too high for elderly Japanese patients with an average body weight of only 50 kg, resulting in excessive toxicity and cost. We therefore initiated a study to investigate whether osimertinib at 40 mg/d is non-inferior to 80 mg/d in patients with advanced or recurrent epidermal growth factor receptor-activating mutation-positive non-small cell lung cancer aged ≥70 years, using a regression discontinuity design. Osimertinib is administered at 40 mg/d for body weight ≤50 kg, and 80 mg/d for body weight >50 kg. The primary endpoint is progression-free survival. Sample size is 550 patients, based on a non-inferiority margin of the progression-free survival hazard ratio 1.333, 0.10 one-sided type I error and 80% power.