Astrazeneca plc has won FDA approval to market Fasenra (benralizumab) as an add-on maintenance therapy for severe, eosinophilic asthma patients, age 12 years and older. Injected every eight weeks after a run-in period, the monoclonal antibody helped trial patients achieve a reduction in their annual asthma exacerbation rates (AAER) of up to 51 percent vs. placebo.