481P - Updated survival outcomes of the phase II study of low starting dose of afatinib as first-line treatment in patients with EGFR mutation-positive non-small cell lung cancer (KTORG1402)

Abstract

BackgroundThe phase II trial evaluated the efficacy and safety of low starting dose of afatinib in patients with advanced epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC). In primary analysis, progression free survival (PFS) met the primary endpoint. Here, we report updated survival outcomes. MethodsThis study was a multi-center, single-arm, open-label phase II trial. Treatment-naïve patients with common EGFR mutation-positive NSCLC were treated with afatinib starting at a dose of 20 mg/day. If tolerated, the dose is increased by 10- mg increments up to 50mg/day. PFS and overall survival (OS) were re-evaluated at the final data cut-off point (October 2018). Results46 patients were enrolled. Median age was 73 years (range, 43-86). The median follow-up was 31.9 months. Median PFS of entire population was 15.2 months (95% confident interval (CI), 13.2–21.2), and 2-year PFS rate was 27.7% (95% CI, 17.1-44.7). Median OS was not estimated, and the 2-year overall survival was 76.1% (95% CI, 64.7-89.5). Performance status (PS) and existence of brain metastases at study entry were revealed to have significant impact on the survival with Cox-regression test. Among patients with disease progression on afatinib (n = 36), rebiopsy was performed on 29 patients, and T790M was proved positive on 14 patients. Twelve out of the 14 patients positive for T790M received osimertinib as a second line therapy. Median time from enrollment to progression on the osimertinib (PFS2) was 32.6 months (95%CI: 20.5-NE). ConclusionsLow starting dose afatinib therapy demonstrated promising OS outcome. PS and existence of brain metastases were predictive factors of this therapy. Clinical trial identificationUMIN 000016444. Legal entity responsible for the studyKyoto Thoracic Oncology Research Group. FundingHas not received any funding. DisclosureT. Yokoyama: Honoraria (self): Boehringer Ingelheim Japan; Honoraria (self): Chugai Pharmaceutical; Honoraria (self): Taiho Pharmaceutical; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Novartis; Honoraria (self): AstraZeneca; Honoraria (self): Ono pharmaceutical; Honoraria (self): MSD. H. Yoshioka: Honoraria (self): Boehringer Ingelheim; Honoraria (self): Chugai Pharmaceutical; Honoraria (self): Taiho Pharmaceutical; Honoraria (self): Eli Lilly Japan; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Novartis; Honoraria (self): Merck Serono; Honoraria (self): Kyowa Kirin; Honoraria (self): AstraZeneca; Honoraria (self): Ono pharmaceutical; Honoraria (self): Daiichi Sankyo; Honoraria (self): MSD. D. Fujimoto: Honoraria (self), Research grant / Funding (self): AstraZeneca KK; Honoraria (self): Ono Pharmaceutical Co Lt; Honoraria (self): Bristol-Myers Squibb Co Ltd; Honoraria (self): Taiho Pharmaceutical Co ; Honoraria (self), Research grant / Funding (self): Chugai Pharmaceutical Co Ltd; Honoraria (self): MSD KK; Honoraria (self): Boehringer Ingelheim Japan Inc; Honoraria (self): Eli Lilly Japan KK. K. Hirano: Honoraria (self): Boehringer Ingelheim Japan. T. Ishida: Honoraria (self): Boehringer Ingelheim Japan. T. Hirai: Research grant / Funding (institution): Boehringer Ingelheim Japan. All other authors have declared no conflicts of interest.