Epidermal growth factor receptor (EGFR) amplification rates observed in screening patients for randomized trials in glioblastoma

Purpose Epidermal growth factor receptor (EGFR) amplifcation has been reported to occur in ~ 50% of glioblastomas (GBMs). We are conducting several global studies that require central testing for EGFR amplifcation during screening, representing an opportunity to confrm the frequency of amplifcation in GBM in a large cohort and to evaluate whether EGFR amplifcation difers by region of the world. Methods EGFR amplifcation was measured by fuorescence in situ hybridization during screening for therapeutic trials of an EGFR antibody–drug conjugate: two Phase 2/3 global trials (INTELLANCE-1, INTELLANCE-2), and a Japanese Phase 1/2 trial (INTELLANCE-J). We evaluated the proportion of tumor tissue samples harboring EGFR amplifcation among those tested and diferences in amplifcation frequency by geography. Results EGFR was amplifed in 54% of 3150 informative cases screened for INTELLANCE-1 and -2, consistent with historic controls, but was signifcantly lower in patients from Asia versus the rest of the world (35% vs. 56%, P<0.0030). The independent INTELLANCE-J trial validated this fnding (33% amplifed of 153 informative cases). Conclusions EGFR amplifcation occurs less frequently in patients from Asia than elsewhere. Further study is required to understand biological diferences to optimize treatment in glioblastoma.

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