A Randomized, Double-blind, Placebo-Controlled, Phase 2 Study to Evaluate the Efficacy and Safety of Mono and Combination Therapy With Monoclonal Antibodies in Participants With Mild to Moderate COVID-19 Illness (BLAZE-4)

• For low-risk participant arms 9-11 only: Are greater than or equal to (≥)18 and less than (\<)65 years of age at the time of randomization and do not have the risk factors defined in the bullet point directly below

• For high-risk participant arms 12 and 13 only:

⁃ - Are ≥18 years of age and satisfy at least one of the following risk factors at the time of screening

⁃ Are ≥65 years of age

⁃ Have a body mass index (BMI) ≥ 35

⁃ Have chronic kidney disease

⁃ Have type 1 or type 2 diabetes

⁃ Have immunosuppressive disease

⁃ Are currently receiving immunosuppressive treatment, or

⁃ Are ≥55 years of age AND have

• cardiovascular disease, OR

∙ hypertension, OR

∙ chronic obstructive pulmonary disease or other chronic respiratory disease

• For high-risk participant arms 12 and 13 only:

‣ Are 12-17 years of age (inclusive) AND satisfy at least one of the following risk factors at the time of screening

• Have a BMI ≥85th percentile for their age and gender based on CDC growth charts, https://www.cdc.gov/growthcharts/clinical_charts.htm

∙ Have sickle cell disease

∙ Have congenital or acquired heart disease

∙ Have neurodevelopmental disorders, for example, cerebral palsy

∙ Have a medical-related technological dependence, for example, tracheostomy, gastrostomy, or positive pressure ventilation (not related to COVID-19)

∙ Have asthma or reactive airway or other chronic respiratory disease that requires daily medication for control

∙ Have type 1 or type 2 diabetes

∙ Have chronic kidney disease

∙ Have immunosuppressive disease, or

∙ Are currently receiving immunosuppressive treatment.

⁃ For high-risk participants arm 14 only:

• Are ≥12 years of age and satisfy at least one of the following risk factors at the time of screening Are ≥65 years of age

• Are adults (≥18 years of age) with BMI \>25 kg/m2 , or if age 12-17, have BMI ≥85th percentile for their age and gender based on CDC growth charts

• Have chronic kidney disease

• Have type 1 or type 2 diabetes

• Have immunosuppressive disease

• Are currently receiving immunosuppressive treatment

• Have cardiovascular disease (including congenital heart disease) or hypertension

• Have chronic lung diseases (for example, chronic obstructive pulmonary disease, asthma \[moderate-to-severe\], interstitial lung disease, cystic fibrosis and pulmonary hypertension)

• Have sickle cell disease

• Have neurodevelopmental disorder (for example, cerebral palsy) or other conditions that confer medical complexity (for example, genetic or metabolic syndromes and severe congenital anomalies)

• Have a medical-related technological dependence (for example, tracheostomy, gastrostomy, or positive pressure ventilation \[not related to COVID-19\]

• Are currently not hospitalized

• Have one or more mild or moderate COVID-19 symptoms: Fever, cough, sore throat, malaise, headache, muscle pain, gastrointestinal symptoms, or shortness of breath with exertion, nasal congestion or runny nose, new loss of smell, chills

• Must have sample taken for test confirming viral infection no more than 3 days prior to starting the drug infusion

• Are men or non-pregnant women who agree to contraceptive requirements

• Understand and agree to comply with planned study procedures

• Agree to the collection of nasopharyngeal swabs and venous blood

• The participant or legally authorized representative give signed informed consent and/or assent