Sequential Afatinib and Osimertinib in Asian Patients with EGFR Mutation-Positive Non-Small Cell Lung Cancer and Acquired T790M: Combined Analysis of Two Global Non-Interventional Studies

Objective: Two recent non-interventional trials, GioTag and UpSwinG, demonstrated encouraging time-to-treatment failure (TTF) and overall survival (OS) in patients with epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC) (Del19 or L858R) who received sequential afatinib/osimertinib, especially in Asians. Here, we have undertaken a combined analysis of Asian patients from both studies. Materials and Methods: Existing medical/electronic records were identified for consecutive EGFR-tyrosine kinase inhibitor (TKI)-naive patients who received first-line afatinib/second-line osimertinib in "real-world" practice (all T790M-positive). Patients with active brain metastases were excluded. The primary objective was TTF. OS was a key secondary objective. Results: One hundred and sixty-eight patients were analyzed. Most patients were recruited from South Korea or Japan (52/21%). At the start of afatinib, median age (range) was 61.5 years (35-88), 58% were female, Eastern Cooperative Oncology Group Performance Status (ECOG PS) (0/1/>= 2) was 29/62/9%, 17% had brain metastases, and EGFR mutation status (Del19/L858R) was 65/35%. At the start of osimertinib, ECOG PS (0/1/>= 2) was 22/61/17% and 14% had brain metastases. Median TTF and OS were 30.0 months (95% CI: 24.5-32.5) and 45.2 months (95% CI: 41.7-71.1), respectively. Median OS was 63.5 months in patients with a Del19 mutation. Median OS in patients with brain metastases or ECOG PS >= 2 was 26.4 and 33.1 months, respectively. Conclusion: Sequential afatinib/osimertinib showed encouraging activity in Asian patients with EGFR mutation-positive NSCLC and T790M-mediated acquired resistance, especially those with Del19-positive disease. Activity was observed across "real-world" patients including those with poor ECOG PS and/or brain metastases. ECOG PS and incidence of brain metastases remained stable prior to, and after, afatinib.