Emerging SARS-CoV-2 variants impacting susceptibility to study drug

The primary objective of the study is to characterize the concentrations of casirivimab+imdevimab in serum over time after a single subcutaneous (SC) administration

The secondary objectives of the study are:

• To assess the safety and tolerability of SC or single administration of casirivimab+imdevimab
• To assess the occurrence of grade ≥3 injection site reactions and grade ≥3 hypersensitivity reactions, in participants treated with SC doses of casirivimab+imdevimab
• To assess the immunogenicity of casirivimab+imdevimab

Key Inclusion Criteria:

1. Is <12 years of age and ≥3 kg to <40 kg at the time parental/guardian consent is signed

2. Has at least one risk factor for developing severe COVID-19 if they were to become infected, such as:

   1. Obesity (BMI [kg/m2] ≥95th percentile for age and sex based on CDC growth charts)
   2. Cardiovascular disease
   3. Chronic lung disease
   4. Type 1 or type 2 diabetes mellitus
   5. Chronic kidney disease, including those on dialysis
   6. Chronic liver disease
   7. Immunocompromised or immunodeficient, based on Investigator's assessment (examples include cancer treatment, bone marrow or organ transplantation, immune deficiencies, HIV infection, sickle cell anemia, thalassemia, and prolonged use of immune-weakening medications)
   8. Medical complexities (examples include any underlying genetic condition, neurologic condition, metabolic condition, or congenital heart disease)
   9. Any other condition deemed by the Investigator to be a risk factor for severe COVID-19

Key Exclusion Criteria:

1. Has positive diagnostic test for SARS-CoV-2 infection from a sample collected during screening ≤7 days prior to study drug administration Note: The sample for the test should be collected ≤7 days within study drug administration, and the result should be reviewed and confirmed negative prior to dosing. Historical records will not be accepted.
2. Has active respiratory or non-respiratory symptoms consistent with COVID-19 in the opinion of the Investigator
3. Has subject-reported clinical history of COVID-19, as determined by Investigator, within the last 90 days
4. Has subject-reported history of prior Emergency Use Authorization (EUA)/approved positive diagnostic test for SARSCoV-2 infection within the last 90 days
5. Is currently hospitalized or was hospitalized for >24 hours for any reason within 14 days of the screening visit
6. Prior use (within 90 days prior to study drug administration) or current use of any investigational, authorized, or approved passive antibody for prophylaxis of SARS-CoV-2 infection, including convalescent plasma, convalescent sera, hyperimmune globulin, or other monoclonal antibodies (eg, bamlanivimab and etesevimab, sotrovimab)
7. Has initiated vaccination for SARS-CoV-2 with an investigational or approved vaccine, but has not completed the vaccine schedule as recommended by the vaccine manufacturer.
8. Plans to receive an investigational or approved SARS-CoV-2 vaccine within 90 days after study drug administration, or per the recommended time frame from the current Centers for Disease Control vaccination guidelines (CDC, 2021b)

NOTE: Other protocol-defined Inclusion/ Exclusion Criteria apply

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

When Regeneron has received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication, has made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry), has the legal authority to share the data, and has ensured the ability to protect participant privacy.

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf

The investigator has the right to independently publish study results from the investigator's site after a multi-center publication, or a defined period after the completion of the study by all sites. The investigator must provide the sponsor a copy of any such publication derived from the study for review and comment in advance of any submission, and delay publication, if requested, to allow the Sponsor to preserve its proprietary rights.