LAUSR

BACKGROUND Dacomitinib significantly improves progression-free survival and overall survival (OS) compared with gefitinib in patients with non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR)-activating mutations. However, dacomitinib often causes skin toxicities, resulting in treatment discontinuation. We aimed to evaluate a prophylactic strategy for skin toxicity induced by dacomitinib. METHODS We performed a single-arm, prospective, open-label, multi-institutional phase II trial for comprehensive skin toxicity prophylaxis. Patients with NSCLC harboring EGFR-activating mutations were enrolled and received dacomitinib with comprehensive prophylaxis. The primary endpoint was the incidence of skin toxicity (Grade ≥2) in the initial 8 weeks. RESULTS In total, 41 Japanese patients participated between May 2019 and April 2021 from 14 institutions (median age 70 years; range: 32-83 years), 20 were male, and 36 had a performance status of 0-1. Nineteen patients had exon 19 deletions and L858R mutation. More than 90% of patients were perfectly compliant with prophylactic minocycline administration. Skin toxicities (Grade ≥2) occurred in 43.9% of patients (90% confidence interval [CI], 31.2%-56.7%). The most frequent skin toxicity was acneiform rash in 11 patients (26.8%), followed by paronychia in five patients (12.2%). Due to skin toxicities, eight patients (19.5%) received reduced doses of dacomitinib. The median progression-free survival was 6.8 months (95% CI, 4.0-8.6 months) and median OS was 21.6 months (95% CI, 17.0 months-not reached). CONCLUSION Although the prophylactic strategy was ineffective, the adherence to prophylactic medication was quite good. Patient education regarding prophylaxis is important and can lead to improved treatment continuity.