Clinical analysis of EGFR-positive non-small cell lung cancer patients treated with first-line afatinib: A Nagano Lung Cancer Research Group.

Background: In the LUX-Lung 3 and LUX-Lung 6 trials, afatinib improved overall survival in previously untreated patients with EGFR 19del mutated non-small cell lung cancer (NSCLC) compared to chemotherapy. The appropriate management of adverse events and dose reduction of afatinib are important for EGFR-positive NSCLC patients. We conducted a retrospective and observational study of patients treated with first-line afatinib for EGFR-positive NSCLC in Nagano prefecture, Japan, focusing on efficacy and toxicities.

Methods: We retrospectively collected the medical records of NSCLC patients initially treated with afatinib between May 2014 and March 2018.

Results: A total of 62 patients with a median age of 67 years and a median body surface area (BSA) of 1.57 m were included. The overall response rate was 87.7% and median progression-free survival (PFS) was 15.7 months. The median PFS was similar between standard initial dose (40 mg) and reduced initial doses (30 and 20 mg) (15.7 vs. 14.2 months; P = 0.978). The frequency of dose reduction and the discontinuation rate in the 40 mg daily dose group was higher in patients with BSA < 1.58 m (100%) compared to BSA ≥ 1.58 m (68.2%) (P = 0.014). The frequency of diarrhea was higher in patients with BSA < 1.58 m (93.5%) compared to BSA ≥ 1.58 m (71.0%) (P = 0.02).

Conclusion: In real-world clinical practice, first-line afatinib was well managed and was equally as effective as in previous clinical trials of EGFR-positive NSCLC. BSA is considered a predictive marker for appropriate afatinib dose reduction.