LAUSR

2003Background: GBM is the most common malignant primary brain tumor in adults. Pts with rGBM have a poor prognosis. EGFR is amplified (amp) in ~50% of GBMs and is a compelling therapeutic target. ABT-414 is an antibody-drug conjugate composed of an EGFR-directed antibody conjugated to a microtubule toxin, MMAF. ABT-414 binds a unique epitope exposed during EGFR activation, either through ligand stimulation or mutation such as EGFR variant III (EGFRvIII), releasing MMAF into the cancer cell. Here, we report a pooled safety and efficacy analysis of ABT-414 +/- TMZ in EGFR amp, rGBM. Methods: M12-356 is a Phase 1, open-label, multi-arm study. Results from the 2 arms accruing rGBM pts were pooled for analysis. Eligible adults had rGBM, centrally confirmed EGFR amp, and KPS ≥ 70. Pts received 0.5-1.25 mg/kg ABT-414 on days 1 and 15 +/- 150-200 mg/m2 TMZ on days 1-5 of 28-day cycles until progression (per RANO). Results: As of 11 January 2017, 126 pts were treated. The most common adverse events (AEs, ≥ 25% pt...