517PA real-world study of osimertinib: ASTRIS 2nd DCO Korean subgroup analysis

Background: ASTRIS (NCT02474355) is a phase III, open-label, single-arm, multinational, real world study, investigating safety and efficacy of osimertinib in patients (pts) with T790M-positive advanced non-small cell lung cancer (NSCLC), who have previously received EGFR-TKI. As the largest real world study of osimertinib, ASTRIS has globally enrolled 3,014 pts; 466 were from Korea. We report the interim analysis (data cut-off (DCO): 20 Oct 2017) of Korean subset. Methods: Eligible pts had advanced NSCLC with confirmed T790M mutation with no history of interstitial lung disease (ILD) or QTc prolongation. Pts with asymptomatic, stable CNS metastases were enrolled. Pts received osimertinib 80 mg once daily. The primary efficacy outcome was overall survival; other outcomes included investigator-assessed response rate (RR), progression-free survival (PFS), time to treatment discontinuation (TTD) and safety. Results: A total of 466 pts received at least one dose of osimertinib from 31 Korean sites. Baseline pts’ characteristics were median age 61.2 (27–85) years, 47.4% had prior chemotherapy and 46.8% had prior radiotherapy. At DCO, 236 pts (50.6%) were ongoing and median follow-up time was 11.6 (0–18) months. 49.4% had treatment discontinuation; median duration of exposure 11.2 (0–19) months, 35.2% had disease progression and 19.7% died. In pts evaluable for response, defined as at least one dose of osimertinib and one response assessment, the investigator-assessed RR was 71.0% (320/451; 95% CI 66.5 – 75.1). Median PFS and TTD were 12.4 months (10.6-13.6 months) and 15months (12.7-16.5). Due to limited follow-up period, OS was immature to analyze. Adverse events (AEs) leading to dose modification including treatment discontinuation was reported in 12.0%. Serious AEs were reported in 24.9% and AEs leading to death were reported in 2.8%. ILD/pneumonitis-like events were reported in 1.7%, and QTc prolongation (>470ms) in 1.5%. Conclusions: With additional follow-up, ASTRIS Korean subgroup continues to demonstrate similar clinical activities (RR) and safety to that observed in the other osimertinib clinical trials. Clinical trial identification: NCT02474355. Legal entity responsible for the study: AstraZeneca. Funding: AstraZeneca. Disclosure: All authors have declared no conflicts of interest.