Inclusion Criteria:

• Male or female aged 18 through 70 years.
• Physician-diagnosed asthma requiring continuous treatment with medium- or high-dose ICS plus LABA with or without additional controller medication for at least 12  months prior to Visit 1, and current treatment with high-dose ICS plus LABA for at least 3 months prior to Visit 1 with or without additional asthma maintenance medication.
• Morning pre-BD FEV1 ≥ 50 to < 80% of predicted normal value (PNV) and ≥ 1 liter (L) or morning pre-BD FEV1 ≥ 50 to < 90% of PNV, if historical pre-BD FEV1 value (within 12 months prior to screening visit) was < 80% of PNV.
• A blood eosinophil count meeting any of 3 criteria below:
  • ≥ 300 cells/µL during screening at Visit 1 or Visit 2; OR
  • ≥ 220 to < 300 cells/µL during screening at Visit 1 or Visit 2 and documented eosinophil count of ≥ 300 cells/µL in the past 12 months; OR
  • ≥ 150 to < 300 cells/µL during screening at Visit 1 or Visit 2 PLUS one of the following:
  • Presence of nasal polyps; or
  • Pre-BD FVC < 65% predicted at Visit 2.
• Negative pregnancy test.
• Asthma control questionnaire (ACQ-6) > 1.5.
• Fewer than 12 exacerbations within the 6 months prior to Visit 3.

Exclusion Criteria:

• Any disease or concomitant medication which could affect study results or safety of study participants, including:
  • current smokers;
  • history of cancer;
  • life-threatening asthma;
  • clinically important pulmonary disease other than asthma.
• Use of chronic immunosuppressive medication or receipt of immunoglobulin (or blood products) within 30 days prior to the date informed consent is obtained.
• Previously received:
  • benralizumab;
  • live attenuated vaccines 30 days prior to the date of  randomization;
  • bronchial thermoplasty in the last 24 months prior to Visit 1;
  • any investigational non-biologic within 22 days (or 5 half-lives) prior to the date informed consent is obtained, whichever is longer; 
  • Receipt of any marketed (eg, omalizumab, mepolizumab and reslizumab) or investigational biologic for the treatment of asthma within 4 months or 5 half-lives prior to the date informed consent is obtained, whichever is longer. Exception: Participants on stable therapy for 3 months prior to the date informed consent is obtained can participate in the study if they intend to stay on treatment throughout the study with marketed biologic products that are not likely to interfere with the safety assessment and/or efficacy of benralizumab (eg, for the treatment of osteoporosis, migraine, pain, diabetes, obesity, ocular, cardiovascular, or metabolic diseases).
• Currently pregnant, breastfeeding or lactating women.
• Radiological findings suggestive of a respiratory disease other than asthma that is contributing to the participant’s respiratory symptoms. Radiological findings of pulmonary nodules suspicious for lung cancer, as per applicable guidances, eg, ACR Lung-RADS v2022, (ACR 2022) without appropriate follow-up prior to randomization. Radiological findings suggestive of acute infection. Screening period may be extended for cases of acute infection and based on case-by-case discussion between investigator and AstraZeneca Study Physician.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 1/2/24. Questions regarding updates should be directed to the study team contact.