COVID-19 Administration of Single-Dose Subcutaneous Anti- Spike(s) SARS-CoV-2 Monoclonal Antibodies Casirivimab and Imdevimab in High-Risk Pediatric Participants Under 12 Years of Age

A Phase 2A, Open-Label Study Assessing Pharmacokinetics, Safety, Tolerability, and Immunogenicity of Single-Dose Subcutaneous Anti- Spike(s) SARS-COV-2 Monoclonal Antibodies (Casirivimab and Imdevimab) in High-Risk Pediatric Subjects Under 12 Years of Age

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

Study Overview

• Status: Terminated
• Conditions: COVID-19
• Intervention / Treatment: Drug: casirivimab+imdevimab

• Study Type: Interventional
• Enrollment (Actual): 7
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • California
    • Anaheim, California, United States, 92805
      • Advanced Research Center, Inc
  • Florida
    • Miami, Florida, United States, 33136
      • Batchelor's Children's Research Institute
  • New York
    • Stony Brook, New York, United States, 11794
      • Stony Brook University Hospital
    • Syracuse, New York, United States, 13210
      • SUNY Upstate Medical University
    • The Bronx, New York, United States, 10461
      • Jacobi Medical Center
  • South Carolina
    • Charleston, South Carolina, United States, 29414
      • Coastal Pediatric Research
  • Virginia
    • Richmond, Virginia, United States, 23226
      • Regeneron Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 minute to 12 years (Child)
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ≥20 kg to <40 kg; SC administration	Drug: casirivimab+imdevimab; Single dose administered based on weight; Other Names: REGN-COV2; REGEN-COV™; REGN10933-10987; RONAPREVE™
Experimental: ≥10 kg to <20 kg; SC administration	Drug: casirivimab+imdevimab; Single dose administered based on weight; Other Names: REGN-COV2; REGEN-COV™; REGN10933-10987; RONAPREVE™
Experimental: ≥5 kg to <10 kg; SC administration	Drug: casirivimab+imdevimab; Single dose administered based on weight; Other Names: REGN-COV2; REGEN-COV™; REGN10933-10987; RONAPREVE™
Experimental: ≥3 kg to <5 kg; SC administration	Drug: casirivimab+imdevimab; Single dose administered based on weight; Other Names: REGN-COV2; REGEN-COV™; REGN10933-10987; RONAPREVE™

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentrations of Casirivimab+Imdevimab in Serum Over Time.	Concentrations reported in milligrams per Liter (mg/L)	Day 0 and Day 14

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Treatment-Emergent Adverse Events (TEAEs)		Through end of study, approximately 24 weeks
Number of Participants With Indicated Severity of TEAEs	Treatment-emergent adverse events (TEAEs) are defined as those that are not present at baseline or represent the exacerbation of a pre-existing condition during the on-treatment period. The severity of AEs were graded using version 5.0 of NCI-CTCAE.	Through end of study, approximately 24 weeks
Number of Participants With Grade ≥3 Injection Site Reactions		Through Day 4
Number of Participants With Grade ≥3 Hypersensitivity Reactions		Through Day 4
Number of Participants With Indicated Immunogenicity as Measured by Anti-drug Antibodies (ADA) to Casirivimab Over Time		Up to 24 weeks
Number of Participants With Indicated Immunogenicity as Measured by ADA to Imdevimab Over Time		Up to 24 weeks
Immunogenicity as Measured by Neutralizing Antibodies (NAb) to Casirivimab Over Time		Up to 24 weeks
Immunogenicity as Measured by NAb to Imdevimab Over Time		Up to 24 weeks

Collaborators and Investigators

• Sponsor: Regeneron Pharmaceuticals
• Investigators: Study Director: Clinical Trial Management, Regeneron Pharmaceuticals

Study record dates

Study Major Dates

• Study Start (Actual): September 13, 2021
• Primary Completion (Actual): June 1, 2022
• Study Completion (Actual): June 1, 2022

Study Registration Dates

• First Submitted: August 3, 2021
• First Submitted That Met QC Criteria: August 3, 2021
• First Posted (Actual): August 5, 2021

Study Record Updates

• Last Update Posted (Actual): October 20, 2025
• Last Update Submitted That Met QC Criteria: October 9, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: coronavirus; Coronavirus disease 2019 (COVID-19); Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2)
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronaviridae Infections; Nidovirales Infections; COVID-19; Coronavirus Infections; casirivimab and imdevimab drug combination
• Other Study ID Numbers: R10933-10987-COV-2121; 2021-004590-30 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
• IPD Sharing Time Frame: 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.
• IPD Sharing Access Criteria: 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
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No