Abstract 5515
Background
EGFR tyrosine kinase inhibitors (EGFR-TKIs) are standard therapy for EGFRm aNSCLC. Upon progression, 50-60% will develop the secondary T790M mutation. Recent trials demonstrated improvement in outcomes with osimertinib over standard platinum-based chemotherapy as 2L therapy for T790M-positive EGFRm aNSCLC. To identify T790M, tumour biopsy or plasma testing is necessary. This study aimed to evaluate biopsy procedures and mutational analysis at two Canadian cancer centres.
Methods
BC Cancer-Vancouver and Cross Cancer Institute performed a retrospective review of pts who signed consent to enroll to the AURA2, AURA3 or ASTRIS studies. Pt characteristics, biopsy method, rebiopsy methods/complications, number of rebiopsies performed, and incidence of the T790M mutation were collected.
Results
84 pts were considered for trial enrolment. 80 signed consent with M:F 32:68%; ECOG 0/1/2: 11/66/23%; smoker/ex-smoker/never smoker: 6/21/73%; exon 19/L858R/other: 60/36/4%; prior curative intent treatment in 18%. 78 pts underwent biopsy, most commonly CT/US-guided biopsy (50%), bronchoscope/EBUS (32%), thoracentesis/surgical biopsy (12%). 3 pts had plasma testing. Type of biopsies were cores (47%), fine needle biopsy (18%), transbronchial biopsy (14%), other (21%). The most common sites for biopsy were lung or nodes (64%). The median number of biopsies performed was 2. Only 8% of pts experienced complications after biopsy. 77% of samples were adequate for T790M testing: 35% performed locally, 65% centrally. Overall, 47 pts were found to have T790M; of which, 44 were enrolled in a trial. Among 40 pts who were ineligible for trials, reasons included: T790M negative (72.5%), decline in performance status/death (15%), inadequate tissue (5%), biopsy refusal, unable to biopsy, and symptomatic brain metastases requiring radiation (2.5% each). Additional data on practice pattern will be presented.
Conclusions
Patients and physicians were amenable to re-biopsy at progression for further tumor characterization and treatment selection. The incidence of complications was low despite the majority being pulmonary biopsies. 23% of the samples were not adequate for molecular analysis.
Clinical trial identification
Legal entity responsible for the study
University of Alberta, Alberta Health Services, Cross Cancer Institute and AstraZeneca.
Funding
AstraZeneca.
Editorial Acknowledgement
Disclosure
Q.S-C. Chu: Honorarium: AstraZeneca, BMS, BI, Eisai, Lily, Merck, Novartis, Roche, Takeda; Research funding: AstraZeneca. N.C. Devost, R. Walton: Employee: AstraZeneca. C. Ho: Honorarium and research funding: AstraZeneca. All other authors have declared no conflicts of interest.