Abstract
BACKGROUND
EGFR is a key oncogenic target for the treatment of glioblastoma. EGFR amplification is detected in ~50% of tumors. Depatuxizumab mafodotin (depatux-m), formerly called ABT-414, is a tumor-specific antibody-drug conjugate that preferentially targets tumors with EGFR amplification. Herein, we report the frequency of EGFR amplification in 2 large-scale glioblastoma clinical trials of depatux-m.
METHODS
As of May 1, 2017, testing for EGFR amplification status was performed centrally in 2077 glioblastoma samples during screening for 2 randomized glioblastoma trials with depatux-m: INTELLANCE 1 (NCT02573324) for newly diagnosed patients (n=1001), and INTELLANCE 2 (NCT02343406) for recurrent disease (n=1076). EGFR amplification, required for eligibility in both trials, was determined by fluorescence in situ hybridization and defined as at least 2 copies in at least 15% of cells. EGFRvIII mutation data will be reported at the meeting.
RESULTS
Out of 2077 total patients, 1084 were positive for EGFR amplification (52.2%), similar to published rates. Per world region number and frequency of EGFR amplification was as follows: Africa (4/9; 44.4%), Americas (238/451; 52.8%), Asia (69/201; 34.3%), Europe (672/1190; 56.5%), Middle East (21/40; 52.5%), Oceania (80/186; 43.0).
CONCLUSIONS
To our knowledge, this study represents the first report of lower EGFR amplification rates in patients from Asia with glioblastoma. This observation requires further study.