Real-world use of osimertinib for epidermal growth factor receptor T790M-positive non-small cell lung cancer in Japan

Adverse drug reactions (ADRs) during real-world osimertinib use were investigated in Japan. Patients with epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer treated with second-line or later oral osimertinib per the Japanese package insert (80 mg once daily) were included. Data were collected between 28 March 2016 and 31 August 2018. The median observation period in the safety analysis population (n = 3578) was 343.0 days. ADRs (defined as adverse events whose causality to osimertinib could not be denied by the attending physicians or manufacturer) were reported in 58.1% (2079/3578) of patients. ADRs of interstitial lung disease events were reported in 6.8% (245/3578; Grade ≥ 3, 2.9% [104/3578]) of patients, of whom 29 (11.8%) died (0.8% of patients overall). ADRs of QT interval prolonged, liver disorder and haematotoxicity were reported in 1.3% (45/3578; Grade ≥ 3, 0.1% [5/3578]), 5.9% (212/3578; Grade ≥ 3, 1.0% [35/3578]) and 11.4% (409/3578; Grade ≥ 3, 2.9% [104/3578]) of patients, respectively. In the efficacy analysis population (n = 3563), 119 (3.3%) patients had complete responses, 2373 (66.6%) had partial responses and 598 (16.8%) had stable disease. The objective response rate was 69.9%; disease control rate was 86.7%; and median progression-free survival (PFS) was 12.3 months. At 6 and 12 months, PFS rates were 77.4% (95% confidence interval [CI], 75.9-78.9) and 53.2% (95% CI, 51.3-55.1) and overall survival rates were 88.3% (95% CI, 87.2-89.4) and 75.4% (95% CI, 73.8-77.0), respectively. These data support the currently established benefit-risk assessment of osimertinib in this patient population.