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

Inclusion Criteria:

- Female and male patients aged 12 to 21 years, inclusive, at the time of Visit 1

- Weight of ≥40 kg

- Documented history of current treatment with Inhaled corticosteroids (ICS) and
long-acting β2 agonists (LABA)

- Morning pre-bronchodilator forced expiratory volume in 1 second (FEV1) of >50%
predicted at Visit 1 or Visit 2.

- Airway reversibility (FEV1 >12% and 200 ml) demonstrated at Visit 1 or Visit 2 using
the Maximum Post-bronchodilator Procedure OR

- Airway reversibility documented in the previous 12 months prior to Visit 1

- An exacerbation, 1 or more, that required oral corticosteroids in the previous year OR

- Any condition assessed by patient recall over the previous 2-4 weeks

Exclusion Criteria:

- Clinically important pulmonary disease other than asthma

- Known history of allergy or reaction to the Investigational Product formulation or
influenza vaccine

- Receipt of an influenza vaccine within 90 days prior to randomization

- Poorly controlled asthma during the screening period that requires treatment with oral
corticosteroids or a hospitalization/emergency room visit for the treatment of asthma

- Acute illness or evidence of significant active infection or known influenza infection
during the current flu season