1290POBSERVATIONAL STUDY OF TREATMENT WITH EPIDERMAL GROWTH FACTOR RECEPTOR TYROSINE KINASE INHIBITORS (EGFR-TKI) IN ACTIVATING EGFR MUTATION-POSITIVE (EGFRM+) ADVANCED OR RECURRENT NON-SMALL-CELL LUNG CANCER (NSCLC) AFTER RADIOLOGICAL PROGRESSION TO FIRST-LINE THERAPY WITH EGFR-TKI

ABSTRACT Aim: NSCLC with activating EGFR mutation is generally sensitive to EGFR-TKIs, but resistance is inevitable. The clinical course after radiological “progressive disease” (PD) judgment is variable and not fully elucidated. Methods: 31 institutions in Japan participated in the survey of patients with EGFRm+ NSCLC who received first-line EGFR-TKIs between 2009 and 2011. The primary endpoint was the time from RECIST-based radiological PD (R-PD) to clinical PD (C-PD) in patients who continuously received TKI beyond R-PD. C-PD was defined as one or more of the following: 1) symptomatic PD; 2) worsening performance status due to PD; 3) threat to major vital organ(s); or 4) multi-organ unequivocal PD. Durations of TKI administration and overall survival (OS) were also recorded. The study fund was provided to the Comprehensive Support for Oncology Research with support from an Investigator Sponsored Study Programme of AstraZeneca. Results: At the time of submission, 579 cases were registered, with 412 analyzed. Objective response rate to the first-line EGFR-TKI was 68.5%. 38 cases were still on TKI without R-PD. The remaining 374 could be sub-classified into the following groups: Group A, TKI stopped at R-PD concurrently occurring with C-PD (n = 140); Group B, TKI stopped at R-PD without C-PD (n = 104); Group C, TKI continued beyond R-PD (n = 63); and Group D, TKI stopped due to other reasons (n = 67). Therefore, 63/167 patients (38%) continued to receive TKI beyond clinically stable R-PD. Median time from R-PD to C-PD or TKI discontinuation in Group C was 4.2 months. Median OS for Groups A, B, C and D were 20.6, 23.3, 27.4 and 13.6 months, respectively, whereas median periods on TKIs were 8.8, 9.9, 18.3 and 2.7 months, respectively. Conclusions: Clinical courses and pattern of care after resistance to EGFR-TKI varied. 38% of the patients without clinical deterioration at R-PD were continued on TKI, for a median period to C-PD of 4.2 months. This group of patients had numerically longer EGFR TKI treatment period and OS. Disclosure: All authors have declared no conflicts of interest.