A randomized, double-blind, 3-arm (1:1:1) study in subjects with first-line Stage IV non-squamous NSCLC. The purpose is to test the efficacy and safety of demcizumab, when given in combination with carboplatin and pemetrexed compared to placebo. The administration of carboplatin and pemetrexed is a standard treatment for patients with non-squamous non-small cell lung cancer.