Study to Evaluate the Potential Effect of Benralizumab on the Humoral Immune Response to the Seasonal Influenza Vaccination in Adolescent and Young Adult Patients With Severe Asthma

This study is designed to investigate the potential effect of benralizumab on the antibody response to the seasonal influenza virus vaccine in patients 12-21 years of age with asthma. Benralizumab will be given subcutaneously (SC) at Weeks 0, 4, and 8 weeks, at which time benralizumab levels will reach steady state. Patients will then receive 1 dose of intramuscular (IM) seasonal influenza virus vaccine at Week 8 and samples drawn at Week 8 and Week 12 to measure the antibody response to the influenza virus