Exploratory biomarker analyses from OAM4558g: A placebo-controlled phase II study of erlotinib with or without MetMAb in patients with advanced non-small cell lung cancer (NSCLC).

7529 Background: MetMAb, a monovalent anti-cMet receptor antibody, inhibits HGF-mediated activation of c-Met. The Phase II study testing MetMAb in combination with erlotinib in patients with advanced NSCLC (n=128) demonstrated an OS benefit in Met Diagnostic (Dx)+ patients (n=65, defined as ≥50% of tumor cells staining 2+ or 3+ intensity for c-Met by IHC; HR=0.37, p=0.002). Methods: Exploratory tumor biomarkers related to c-Met and/or EGFR signaling were measured by FISH, qRT-PCR or various mutation detection techniques from archival tumor tissue specimens. Plasma HGF levels were measured by ELISA. Analyses with outcome were carried out independent of Met Dx status. Results: Baseline characteristics of patients with evaluable tumor or plasma specimens were generally comparable. MET gene copy number was evaluated in 96 specimens with a median mean copy number of 3.44 copies/cell (range 1.6–25.0) and true gene amplification was detected in 8%. Analysis of different copy number cutoffs revealed a non-signifi...