AzTrials
AzTrials

ImmunocompromisedPhase 3NCT05074433

A Study to Evaluate Efficacy and Safety of Casirivimab+Imdevimab (Monoclonal Antibodies) for Prevention of COVID-19 in Immunocompromised Adolescents and Adults

A Phase 3 study testing casirivimab+imdevimab in people with Immunocompromised, run by Regeneron Pharmaceuticals at 67 sites in 2 countries.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
Search all trials

Trial summary

The primary objective of the study is to evaluate the effect of casirivimab+imdevimab, compared with placebo, in preventing symptomatic SARS-CoV-2 infection in immunocompromised participants. Read more about this study

Who is it for?
Ages 12 years and older
Conditions the study is for
Immunocompromised
What is being tested?
casirivimab+imdevimab
Type of treatment
Injection or infusion
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
66 participants
Where
67 sitesin 2 countries
Study dates
25 Oct 2021to 18 May 2022
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 12 years and older
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • Meets ≥1 of the following criteria:
  • Is immunocompromised, including people with transplant, who have cancer, primary immunodeficiencies, HIV, rheumatological disease, autoimmune disease, multiple sclerosis OR
  • Currently taking immunosuppressant drugs
  • Have been fully vaccinated against COVID-19 or deemed medically ineligible to receive full course of vaccine
  • Has documented negative serology/antibody response in an anti-SARS-CoV-2 spike protein IgG clinical test or ≤50 U/mL on the Elecsys® SARS-CoV-2 S Total Ig test
  • Tested negative for the COVID-19 virus within 72 hours prior to randomization

Who cannot join

  • Weighs <40 kg (only applies to participants ≥12 to <18 years of age)
  • Has any signs or symptoms consistent with COVID-19
  • Past COVID-19 infection within 90 days prior to randomization
  • Planned use of any investigational, authorized, or approved vaccine for COVID-19 within 90 days of the last dose of study drug
  • Prior, current, or planned use of any of COVID-19 convalescent plasma, other monoclonal antibodies against SARS-CoV-2 or any COVID-19 treatment
  • Is planned to begin immunoglobulin (IVIG) or immunoglobulin (SCIG) therapy, is planned to have a change to existing IVIG or SCIG, or has been on a chronic stable dose of their IVIG or SCIG regimen for less than 90 days prior to screening
Show all 10Show fewer
  • Has any known active acute respiratory infection
  • Has persistent (refractory to treatment for ≥14 days) bacterial or fungal infection
  • Has known allergy or hypersensitivity to components of the study drugs
  • NOTE: Other Protocol Defined Inclusion/Exclusion Criteria Apply

Trial locations and contacts

67 sites in 2 countries.

67 sites in 2 countries

United States66 sites
  • PharmaTex Research, LLC

    Amarillo, Texas, 79109

  • University of Michigan

    Ann Arbor, Michigan, 48109

  • Regeneron Study Site

    Atlanta, Georgia, 30322

  • University Of Colorado

    Aurora, Colorado, 80045

  • Central Texas Clinical Research

    Austin, Texas, 78705

  • Arthritis and Rheumatic Disease Specialties

    Aventura, Florida, 33180

  • Institute of Human Virology

    Baltimore, Maryland, 21201

  • Johns Hopkins Hospital

    Baltimore, Maryland, 21287

  • Laboratory of Clinical Immunology and Microbiology, NIAID

    Bethesda, Maryland, 20892

  • Central Alabama Research

    Birmingham, Alabama, 35205

  • Tufts Medical Center

    Boston, Massachusetts, 02111

  • Regeneron Study Site

    Boston, Massachusetts, 02115

  • Beth Israel Deaconess Medical Center

    Boston, Massachusetts, 02215

  • Maimonides Cancer Center

    Brooklyn, New York, 11220

  • Gabrail Cancer Center Research

    Canton, Ohio, 44718

  • Great Lakes Clinical Trials - Ravenswood

    Chicago, Illinois, 60625

  • Innovative Research of West Florida, Inc.

    Clearwater, Florida, 33756

  • Regeneron Study Site

    Cleveland, Ohio, 44195

  • Miami Valley Hospital

    Dayton, Ohio, 45409

  • Altoona Center for Clinical Research

    Duncansville, Pennsylvania, 16635

  • Midway Immunology and Research Center

    Ft. Pierce, Florida, 34982

  • Spectrum Health

    Grand Rapids, Michigan, 49503

  • Elixia COVID-19

    Hollywood, Florida, 33024

  • Therapeutic Concepts, PA

    Houston, Texas, 77004

  • Houston Methodist Hospital

    Houston, Texas, 77030

  • MD Anderson Cancer Center

    Houston, Texas, 77030

  • Synergy Group Medical,LLC

    Houston, Texas, 77087

  • University of Iowa

    Iowa City, Iowa, 52242

  • West Tennessee Research Institute

    Jackson, Tennessee, 38305

  • Baptist Health Center for Clinical Research

    Little Rock, Arkansas, 72205

  • Regeneron Study Site

    Long Beach, California, 90806

  • Regeneron Study Site

    Los Angeles, California, 90033

  • Cedars-Sinai Medical Center

    Los Angeles, California, 90048

  • University of Wisconsin - Madison

    Madison, Wisconsin, 53792

  • Regeneron Study Site

    Marietta, Georgia, 30060

  • AppleMed Research Group, LLC

    Miami, Florida, 33126

  • De La Cruz Research Center, LLC

    Miami, Florida, 33184

  • Burke Primary Care

    Morganton, North Carolina, 28655

  • Jersey Shore University Medical Center

    Neptune City, New Jersey, 07753

  • Tulane University

    New Orleans, Louisiana, 70112

  • Icahn School of Medicine at Mount Sinai

    New York, New York, 10029

  • Regeneron Study Site

    New York, New York, 10032-3729

  • Memorial Sloan Kettering Cancer Center

    New York, New York, 10065

  • Regeneron Study Site 2

    New York, New York, 10065

  • Regeneron Study Site

    North Haven, Connecticut, 06473-2195

  • University of Nebraska Medical Center

    Omaha, Nebraska, 68198

  • Stanford University

    Palo Alto, California, 94304

  • Penn Prevention Clinical Research Site

    Philadelphia, Pennsylvania, 19104

  • Temple University

    Philadelphia, Pennsylvania, 19140

  • Regeneron Study Site

    Providence, Rhode Island, 02903

  • Regeneron Study Site

    Richmond, Virginia, 23219

  • Mayo Clinic

    Rochester, Minnesota, 55905

  • Regeneron Study Site

    Rochester, New York, 14642

  • University of California

    Sacramento, California, 95817

  • Fred Hutchinson Cancer Research Center

    Seattle, Washington, 98109

  • Regeneron Study Site

    Seattle, Washington, 98109

  • Swedish Medical Center- First Hill

    Seattle, Washington, 98122

  • Regeneron Study Site

    Stanford, California, 94305

  • Regeneron Study Site

    Syracuse, New York, 13210

  • SUNY Upstate Medical University

    Syracuse, New York, 13215

  • University of South Florida

    Tampa, Florida, 33606

  • Holy Name

    Teaneck, New Jersey, 07666

  • Montefiore Medical Center

    The Bronx, New York, 10467

  • Georgetown University

    Washington D.C., District of Columbia, 20007

  • James R Berenson MD Inc.

    West Hollywood, California, 90069

  • Florida Medical Clinic, LLC

    Zephyrhills, Florida, 33542

Other trials in United States

Mexico1 site
  • Regeneron Study Site

    Cuauhtémoc, Mexico City, 6700

Other trials in Mexico

About this study

Official title: A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Anti-Spike SARS-CoV-2 Monoclonal Antibodies as Pre-Exposure Prophylaxis to Prevent COVID-19 in Immunocompromised Participants

The primary objective of the study is to evaluate the effect of casirivimab+imdevimab, compared with placebo, in preventing symptomatic SARS-CoV-2 infection in immunocompromised participants.

The secondary objectives of the study are:

  • To evaluate the safety and tolerability of repeated SC injections of casirivimab+imdevimab in the study population
  • To characterize concentrations of casirivimab and imdevimab in serum over time
  • To assess the immunogenicity of casirivimab and imdevimab
Being tested
casirivimab+imdevimab, Placebo
Keywords
Non-response to COVID-19 vaccination, COVID-19, Immunocompromised, weakened immune system
Medical subject headings
COVID-19

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • casirivimab+imdevimabDrug

    Also called REGN-COV2, REGN10933, REGN10987, REGEN-COV™

    Co-administered sequentially subcutaneous (SC)

  • PlaceboDrug

    Administered SC

Study groups in NCT05074433
Study groupRoleWhat they receive
casirivimab+imdevimab Initial + Q4WExperimentalInitial subcutaneous (SC) dose, then SC dose every 4 weeks (Q4W)
Receives: Drug: casirivimab+imdevimab
casirivimab+imdevimab Q4WExperimentalSC dose Q4W
Receives: Drug: casirivimab+imdevimab
casirivimab+imdevimab Q12WExperimentalSC dose every 12 weeks (Q12W)
Receives: Drug: casirivimab+imdevimab
PlaceboPlacebo comparatorSC dose Q4W
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Cumulative Incidence of Symptomatic (Broad Term), RT-PCR-confirmed SARS-CoV-2 Infection Cases During the EAP

    Cumulative incidence of symptomatic (broad term), RT-PCR-confirmed SARS-CoV-2 infection cases during the Efficacy Assessment Period (EAP)

    Measured: The EAP was defined as the day from first dose of study drug to day 169 +/- 7 days

Secondary outcomes (11)
  1. Number of Participants With Grade ≥3 Treatment-emergent Adverse Events (TEAEs) During the EAP

    Measured: The EAP was defined as the day from first dose of study drug to day 169 +/- 7 days

  2. Number of Participants With Grade ≥3 Treatment-emergent Adverse Events (TEAEs) During the Follow-Up Period

    Measured: End of EAP to the end of the Follow-Up Period (Day 169 to 205, approximately ~1 months)

  3. Number of Participants With TEAEs Leading to Study Drug Discontinuation During the EAP

    Measured: The EAP was defined as the day from first dose of study drug to day 169 +/- 7 days

  4. Number of Participants With TEAEs Leading to Study Drug Discontinuation During the Follow-Up Period

    Measured: End of EAP to the end of the Follow-Up Period (Day 169 to 205, approximately ~1 months)

  5. Number of Participants With Treatment-emergent Serious Adverse Events (SAEs) During the EAP

    Measured: The EAP was defined as the day from first dose of study drug to day 169 +/- 7 days

  6. Proportion of Participants With Treatment-emergent Serious Adverse Events (SAEs) During the Follow-Up Period

    Measured: End of EAP to the end of the Follow-Up Period (Day 169 to 205, approximately ~1 months)

  7. Incidence of Adverse Events of Special Interest (AESIs) During the EAP

    Measured: The EAP was defined as the day from first dose of study drug to day 169 +/- 7 days

  8. Concentration of Casirivimab Over Time

    Measured: Up to 28 days postdose for the Q4W groups and 84 days postdose for the Q12 group

  9. Concentration of Imdevimab Over Time

    Measured: Up to 28 days postdose for the Q4W groups and 84 days postdose for the Q12 group

  10. Incidence of Anti-drug Antibodies (ADA) Over Time

    Measured: Up to 28 days postdose for the Q4W groups and 84 days postdose for the Q12 group

  11. Incidence of Neutralizing Antibodies (NAb) to Each mAb Over Time

    Measured: Up to 28 days postdose for the Q4W groups and 84 days postdose for the Q12 group

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted12 Oct 2021
  2. Study start25 Oct 2021
  3. Primary completion18 May 2022
  4. Study completion18 May 2022

Why it stopped: Emerging SARS-CoV2 variants impacting susceptibility to study drug

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Sequential
Masking
Triple blind
Who is masked
Participant, Care provider, Investigator
Enrolment
66 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05074433
Sponsor's protocol ID
R10933-10987-COV-2176
Other IDs
2021-005222-14
Status last verified
Oct 2025
First submitted
8 Oct 2021
Last updated
20 Oct 2025
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing casirivimab+imdevimab in people with Immunocompromised, run by Regeneron Pharmaceuticals at 67 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 20 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 67 sites in United States, Mexico. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 24 Jul 2023). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Cumulative Incidence of Symptomatic (Broad Term), RT-PCR-confirmed SARS-CoV-2 Infection Cases During the EAP (time frame: The EAP was defined as the day from first dose of study drug to day 169 +/- 7 days). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Oct 2025.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in