A 26 week, randomized, double-blind, parallel-group, active controlled, multicenter, multinational safety study evaluating the risk of serious asthma-related events during treatment with Symbicort®, a fixed combination of inhaled corticosteroid (ICS) (budesonide) and a long acting β2-agonist (LABA) (formoterol) as compared to treatment with ICS (budesonide) alone in adult and adolescent (≥12 years of age) patients with asthma.