This multicenter, randomized, double-blind, placebo-controlled study will evaluate the safety and efficacy of onartuzumab in combination with erlotinib in patients with previously untreated, unresectable stage IIIB or IV non-small cell lung cancer identified to carry and activating EGFR mutation and MET-positive. Patients will be randomized to receive either onartuzumab 15 mg/kg intravenously every 3 weeks in combination with erlotinib 150 mg orally daily or placebo in combination with erlotinib. Anticipated time on study treatment is until disease progression or unacceptable toxicity occurs.