This is a randomized, double-blind, parallel group, placebo-controlled study designed to evaluate the efficacy and safety of a fixed 300 mg dose of tralokinumab administered subcutaneously every 2 weeks in adult and adolescent subjects with oral corticosteroid dependent asthma. Approximately120 subjects will be randomized globally. Subjects will receive tralokinumab or placebo, administered via subcutaneous injection at the study site, over a 40-week treatment period.