COVID-19 Study Assessing the Safety and Tolerability of Co-Formulated Anti-Spike (S) SARS-CoV-2 Monoclonal Antibodies (Casirivimab+Imdevimab) in Adult Volunteers

October 9, 2025 updated by: Regeneron Pharmaceuticals

A Phase 1, Randomized, Open-Label Study Assessing the Safety and Tolerability of Co-Formulated Anti-Spike (S) SARS-CoV-2 Monoclonal Antibodies (Casirivimab+Imdevimab) in Adult Volunteers

The primary objective of the study is to assess the safety and tolerability of co-formulated subcutaneous (SC) and intravenous (IV) casirivimab+imdevimab

The secondary objectives of the study are to:

  • Explore variability in the drug concentration profiles of casirivimab and imdevimab after co-formulated subcutaneous (SC) or intravenous (IV) administration
  • Characterize the immunogenicity of casirivimab and imdevimab in serum over time

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
45

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Florida
      • Miami, Florida, United States, 33186
        • Regeneron study Site
      • Winter Park, Florida, United States, 32789
        • Regeneron StudySite

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Key Inclusion Criteria:

  1. Is healthy, or has chronic medical condition(s) that per the opinion of the investigator is (are) stable, well-controlled, and not likely to require medical intervention through the end of study
  2. Does not require medication(s) for co-morbid condition, or has received stable medication(s) for co-morbid condition(s) for at least 6 months prior to screening
  3. Weighs between ≥60 kg and ≤100 kg at the time of screening
  4. Has SARS-CoV-2-negative reverse-transcriptase polymerase chain reaction (RT-PCR) from a sample collected ≤72 hours prior to randomization, using local assay and sample collection and assay standards
  5. Has completed a full course of COVID-19 vaccination more than 6 weeks prior to randomization

Key Exclusion Criteria:

  1. Has active respiratory or non-respiratory symptoms consistent with COVID-19 in the opinion of the Investigator
  2. Has recent SARS-CoV-2 infection that resolved within 6 weeks prior to randomization
  3. Prior use of casirivimab+imdevimab at any time prior to randomization
  4. Prior, current, or planned use during the study of any of the following treatments: COVID-19 convalescent plasma, other monoclonal antibodies against SARS-CoV-2 (eg, bamlanivimab and etesevimab, sotrovimab), intravenous immunoglobulin (any indication), or any other investigational, authorized, or approved agent intended for COVID-19 treatment or prevention (with the exception of COVID-19 vaccines)
  5. Treatment with another investigational drug in the last 30 days or within 5 half-lives of the investigational drug, whichever is longer, prior to screening
  6. Body mass index (BMI) ≥28 kg/m2
  7. Medically-attended acute illness, systemic antibiotics use, or hospitalization for any reason within 30 days prior to screening
  8. Acute exacerbation of a chronic pulmonary condition (eg, chronic obstructive pulmonary disease [COPD], asthma exacerbations) in the past 6 months prior to screening
  9. Uncontrolled hypertension, in the opinion of the investigator
  10. History of heart failure hospitalization, diagnosis of a myocardial infarction, stroke, transient ischemic attack, unstable angina, percutaneous or surgical revascularization procedure (coronary, carotid, or peripheral vascular), or intracardiac device placement (eg, pacemaker) within 12 months prior to screening
  11. Cancer requiring treatment currently or in the past 5 years, except for non-melanoma skin cancer or cervical/anus in-situ
  12. Is pregnant at screening

Note: Other protocol-defined Inclusion/ Exclusion Criteria apply

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Co-formulated casirivimab+imdevimab SC
Randomized 1:1
Drug: Casirivimab+Imdevimab
Randomized 1:1 for intravenous (IV) or subcutaneous (SC) administration
Other Names:
  • REGN-COV2
  • Casirivimab
  • Imdevimab
  • REGEN-COV™
  • Ronapreve™
Experimental: Co-formulated casirivimab+imdevimab IV
Randomized 1:1
Drug: Casirivimab+Imdevimab
Randomized 1:1 for intravenous (IV) or subcutaneous (SC) administration
Other Names:
  • REGN-COV2
  • Casirivimab
  • Imdevimab
  • REGEN-COV™
  • Ronapreve™

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Targeted grade ≥3 treatment-emergent adverse events (TEAEs)
Time Frame: Through end of study, approximately 16 weeks
Through end of study, approximately 16 weeks
Grade ≥3 injection-site reactions (ISRs)
Time Frame: Through end of study, approximately 16 weeks
Through end of study, approximately 16 weeks
Grade ≥2 infusion-related reactions (IRRs)
Time Frame: Through end of study, approximately 16 weeks
Through end of study, approximately 16 weeks
Grade ≥2 hypersensitivity reactions
Time Frame: Through end of study, approximately 16 weeks
Through end of study, approximately 16 weeks
Serious adverse events (SAEs)
Time Frame: Through end of study, approximately 16 weeks
Through end of study, approximately 16 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Concentrations of casirivimab and imdevimab in serum over time
Time Frame: Up to 16 weeks
Up to 16 weeks
Incidence and titer of anti-drug antibodies (ADA) to casirivimab and imdevimab
Time Frame: Up to 16 weeks
Up to 16 weeks
Incidence of neutralizing antibodies (NAb) to casirivimab and imdevimab
Time Frame: Up to 16 weeks
Up to 16 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Regeneron Pharmaceuticals

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Clinical Trial Management, Regeneron Pharmaceuticals

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 7, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 3, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 3, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 4, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 4, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 6, 2022

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 14, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 9, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • R10933-10987-COV-2179

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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