This trial evaluated the efficacy and safety of tezepelumab (AMG 157/MEDI9929), a human monoclonal antibody specific for the epithelial-cell-derived cytokine thymic stromal lymphopoietin (TSLP), in patients whose asthma remained uncontrolled despite treatment with long-acting beta-agonists and medium-to-high doses of inhaled glucocorticoids.<br><b>METHODS</b>: In this phase 2, randomized, double-blind, placebo-controlled trial, we compared subcutaneous tezepelumab at three dose levels with placebo over a 52-week treatment period.