P3.02b-086 ASP8273 Tolerability and Antitumor Activity in TKI-Naïve Japanese Subjects with EGFRmut+ NSCLC: Preliminary Results: Topic: EGFR Clinical

Abstract

ASP8273, an orally administered epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) that inhibits EGFR-activating mutations, has demonstrated clinical activity in ongoing Phase 1/2 studies in subjects with EGFR mutation-positive non-small cell lung cancer (NSCLC). EGFR TKI-naïve adult subjects (≥20 years) with EGFR mutation-positive metastatic or advanced unresectable NSCLC were enrolled in this ongoing, open-label, Phase 2 single-arm study conducted in Japan (NCT02500927). Subjects received once-daily ASP8273 300 mg until discontinuation criteria were met. The primary endpoint was tolerability; the secondary endpoint was antitumor activity (defined by RECIST v1.1). As of 23 February 2016, 31 subjects (12M/19F; median age 64 years [range: 31–82]) with EGFR mutation-positive NSCLC have been enrolled; 25 subjects (81%) were still on study. Based on local testing, 27 (87%) of the 31 enrolled subjects had an ex19del (n=13, 42%) or a L858R (n=14, 45%) EGFR activating mutation; 4 subjects (13%) had other EGFR activating mutations, including 2 subjects (6%) with L861Q. Moreover, 3 subjects (10%) were found to have both an activating mutation as well as the T790M resistance mutation. Tolerability of ASP8273 is presented in Table 1; gastrointestinal disorders were the most commonly reported treatment-emergent adverse events (eg, diarrhea [n=24, 77%], nausea [n=12, 39%], and vomiting [n=8, 26%)]). All subjects had at least 1 post-baseline scan; 1 subject (3%) achieved a confirmed complete response, 13 subjects (42%) had a confirmed partial response, and 15 subjects (48%) had confirmed stable disease (disease control rate: 94% [n=29/31]) per investigator assessment. These preliminary data showed that ASP8273 300 mg is generally well tolerated and demonstrates antitumor activity in TKI-naïve Japanese subjects with EGFR mutation-positive NSCLC.