Afatinib in EGFR TKI-naive patients with locally advanced or metastatic EGFR mutation-positive non-small cell lung cancer: Interim analysis of a Phase 3b study

Objectives: Randomized controlled trials have demonstrated that afatinib is a suitable treatment option for patients with epidermal growth factor receptor mutation-positive (EGFRm +) non-small cell lung cancer (NSCLC). However, such studies often exclude patients treated in routine clinical practice. We report interim results from a Phase 3b, open-label, multicenter, single-arm, exploratory trial, in which afatinib was investigated in a real world setting. Materials and methods: Patients with EGFRm + tyrosine kinase inhibitor (TKI)-naive NSCLC received afatinib 40 mg orally, once-daily, until disease progression, or voluntary withdrawal. Primary objective was safety. Results: Overall, 479 patients received afatinib: median age 65 years, 8 % of patients had an ECOG performance status >= 2, 17 % had brain metastases, and 13 % had tumors containing uncommon mutations only. All but one patient (99.8 %) had an adverse event (AE). Treatment-related AEs (TRAEs; any/grade >= 3) occurred in 97 %/44 % of patients; most common were diarrhea (87 %/16 %) and rash (51 %/11 %). AEs leading to afatinib dose-reduction were reported in 258 patients (54 %), and 37 patients (8 %) discontinued treatment due to a TRAE. Objective response rate was 45.5 %, median duration of response was 14.1 months (95 % CI: 12.2-16.4). Overall median time to symptomatic progression and progression-free survival were 14.9 months (95 % CI: 13.8-17.6) and 13.4 months (95 % CI: 11.8-14.5), respectively, in the overall population and 19.3 months (95 % CI: 15.6-21.8) and 15.9 months (95 % CI: 13.9-19.1) in patients with EGFR exon 19 deletions. Conclusions: Afatinib administration in routine clinical practice was well tolerated with no new safety signals and demonstrated promising efficacy in patients with EGFRm + NSCLC. TRAEs were generally manageable with tolerability-guided dose reductions. Overall, these data independently support findings from randomized controlled trials of afatinib in EGFRm + NSCLC.