SARS-CoV-2Phase 1/2NCT05081388
COVID-19 Study to Evaluate Safety, Tolerability, and Efficacy of REGN14256+Imdevimab for the Treatment of COVID-19 Adult and Adolescent Patients Without Risk Factors for Progression to Severe Disease
A Phase 1/2 study testing REGN14256, imdevimab and casirivimab + imdevimab in people with SARS-CoV-2, run by Regeneron Pharmaceuticals at 28 sites in United States.
Trial summary
Primary Objectives Phase 1 (Safety and Tolerability) Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by treatment-emergent adverse events (TEAEs), injection-site reactions (ISRs), and hypersensitivity reactions Phase 1/2 (Virologic Efficacy) • Evaluate the virologic… Read more about this study
- Who is it for?
- Ages 12 to 65 years
- Conditions the study is for
- SARS-CoV-2
- What is being tested?
- REGN14256, imdevimab and casirivimab + imdevimab
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 25 participants
- Where
- 28 sitesUnited States
- Study dates
- 8 Nov 2021to 30 Jun 2022
- Phase
- Phase 1/2
- 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 to 65 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- For the adolescent cohort in Phase 3 only: Weighs ≥40 kg at randomization
- Has SARS-CoV-2-positive antigen or molecular diagnostic test (by validated SARSCoV-2 antigen, RT-PCR, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal [NP], nasal, oropharyngeal [OP], or saliva) ≤72 hours prior to randomization. A historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization
- Has symptoms consistent with COVID-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe COVID-19 as outlined in the exclusion criteria
- Maintains O2 saturation ≥93% on room air
Who cannot join
- Has a medical condition or other factors associated with high risk for progression to severe COVID-19:
- Cancer
- Cardiovascular disease (such as heart failure, coronary artery disease, cardiomyopathies, congenital heart disease or hypertension)
- Chronic lung disease including chronic obstructive pulmonary disease, asthma (moderate to severe), interstitial lung disease, cystic fibrosis, and pulmonary hypertension
- Chronic kidney disease at any stage
- Chronic liver disease (such as alcohol-related, nonalcoholic fatty liver disease, cirrhosis)
Show all 27Show fewer
- Dementia or other chronic neurological condition
- Diabetes mellitus (type 1 or type 2)
- Immunodeficiency disease or taking immunosuppressive treatment
- Medical-related technological dependence [for example, tracheostomy, gastrostomy, or positive pressure ventilation (not related to COVID-19)]
- Neurodevelopmental disorder (for example, cerebral palsy) or other condition that confers medical complexity (for example, genetic or metabolic syndromes and severe congenital anomalies)
- Overweight (defined as BMI >25 kg/m2) or obesity (defined as BMI ≥30 kg/m2)
- Poorly controlled HIV infection or AIDS
- Pregnancy
- Sickle cell disease or thalassemia
- Stroke or cerebrovascular disease
- Prior, current (at randomization) or planned use (within time period given per CDC guidance [90 days]) of any authorized or approved vaccine for COVID-19
- Was admitted to a hospital for COVID-19 prior to randomization, or is hospitalized (inpatient) for any reason at randomization
- Has a known prior SARS-CoV-2 infection or positive SARS-CoV-2 serologic test
- Has a positive SARS-CoV-2 antigen or molecular diagnostic test from a sample collected >72 hours prior to randomization
- Has participated, or is participating, in a clinical research study evaluating COVID-19 convalescent plasma, mAbs against SARS-CoV-2, or intravenous immunoglobulin (IVIG) within 3 months or within 5 half-lives of the investigational product (whichever is longer) prior to the screening visit
- Prior, current, or any of the following treatments: COVID-19 convalescent plasma, mAbs against SARS-CoV-2, IVIG (any indication), systemic corticosteroids (any indication), or COVID-19 treatments (authorized, approved, or investigational)
- Has known active infection with influenza or other non-SARS-CoV-2 respiratory pathogen, confirmed by a diagnostic test
- Has been discharged, or is planned to be discharged, to a quarantine center
- Has participated, is participating, or plans to participate in a clinical research study evaluating any authorized, approved, or investigational vaccine for COVID-19
- For Phase 1only: Women of childbearing potential (WOCBP) who are unwilling to practice highly effective contraception prior to the initial dose/start of the first treatment and for at least 6 months after study drug administration as described in the protocol
- Note: Other protocol-defined inclusion/ exclusion criteria apply
Trial locations and contacts
28 sites in 1 country.
28 sites in 1 country
United States28 sites
PharmaTex Research, LLC
Amarillo, Texas, 79109
Regeneron Research Site
Ames, Iowa, 50010
Chicago Clinical Research Institute
Chicago, Illinois, 60607
Carolina Medical Research
Clinton, South Carolina, 29325
IACT Health
Columbus, Georgia, 31904
Regeneron Research Site
Dayton, Ohio, 45409
Regeneron Research Site
Ft. Pierce, Florida, 34982
AGA Clinical Trials
Hialeah, Florida, 33012
Advanced Diagnostics Clinic, River Oaks Hospital and Clinics
Houston, Texas, 77027
Regeneron Research Site
Houston, Texas, 77030
Regeneron Research Site
Houston, Texas, 77093
Regeneron Research Site
La Mesa, California, 91941
Forte Family Practice
Las Vegas, Nevada, 89103
Ark Clinical Research
Long Beach, California, 90806
Regeneron Research Site
Loxahatchee Groves, Florida, 33470
Regeneron Research Site
Marrero, Louisiana, 70072
Project 4 Research, Inc.
Miami, Florida, 33125
Universal Medical and Research Center, LLC
Miami, Florida, 33126
Global Medical Trials
Miami, Florida, 33174
Bio-Medical Research LLC
Miami, Florida, 33184
Charisma Research and Medical Center
Miami Lakes, Florida, 33014
PNS Clinical Research, LLC
Mission Viejo, California, 92691
Olive Branch Family Medical Center
Olive Branch, Mississippi, 38654
New York Health and Hospitals / Lincoln
The Bronx, New York, 10451
NYC H+H / Jacobi Medical Center
The Bronx, New York, 10461
Triple O Research Institute, P.A.
West Palm Beach, Florida, 33407
Regeneron Research Site
Wilmington, North Carolina, 28401
Regeneron Research Site
Winter Park, Florida, 32789
About this study
Official title: A Phase 1/2/3 Adaptive Study to Evaluate the Safety, Tolerability, and Efficacy of REGN14256+Imdevimab for the Treatment of COVID-19 Patients Without Risk Factors for Progression to Severe Disease
Primary Objectives Phase 1 (Safety and Tolerability)
- Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by treatment-emergent adverse events (TEAEs), injection-site reactions (ISRs), and hypersensitivity reactions
Read more
Phase 1/2 (Virologic Efficacy) • Evaluate the virologic efficacy of REGN14256+imdevimab and REGN14256 monotherapy compared to placebo, as measured by time-weighted average (TWA) change from baseline in viral load through day 7
Phase 1/2/3 (Clinical Efficacy)
- Evaluate the clinical efficacy of REGN14256+imdevimab compared to placebo, as measured by COVID-19 symptoms resolution
Secondary Objectives Phase 1 (Safety and Tolerability) • Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by treatment-emergent serious adverse events (SAEs)
Phase 2 and Phase 3 (Safety and Tolerability)
- Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by TEAEs, ISRs, hypersensitivity reactions, and SAEs
Phase 1, Phase 2, and Phase 3 (Virologic Efficacy, Drug Concentration, and Immunogenicity)
- Evaluate additional indicators of virologic efficacy of REGN14256+imdevimab and REGN14256 monotherapy
- Characterize the concentration-time profile of REGN14256 administered in combination with imdevimab or alone as a monotherapy
- Assess the immunogenicity of REGN14256 administered in combination with imdevimab or alone as a monotherapy
- Conditions
- SARS-CoV-2
- Being tested
- REGN14256, imdevimab, casirivimab + imdevimab, Placebo
- Keywords
- COVID-19, Non-hospitalized, Low-risk, Symptomatic, Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), coronavirus
- Medical subject headings
- COVID-19, Coronavirus Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
REGN14256Drug
Sub-cutaneous (SC) single dose
imdevimabDrug
Also called REGN10987
SC single dose
casirivimab + imdevimabDrug
Also called REGN10933 + REGN10987, REGN-COV2, REGEN-COV™, Ronapreve™
SC single dose
PlaceboDrug
SC single dose
| Study group | Role | What they receive |
|---|---|---|
| REGN14256 + imdevimab | Experimental | Phase 1, Phase 2: Randomized 1:1:1:1:1 Phase 3: (≥18 Years): Randomized 1:1:1 Phase 3: (Open label) (≥12 and <18 Years) Receives: Drug: REGN14256; Drug: imdevimab |
| REGN14256 | Experimental | Phase 1, Phase 2: Randomized 1:1:1:1:1 Receives: Drug: REGN14256 |
| Imdevimab | Experimental | Phase 1, Phase 2: Randomized 1:1:1:1:1 Receives: Drug: imdevimab |
| casirivimab + imdevimab | Experimental | Phase 1, Phase 2: Randomized 1:1:1:1:1 Phase 3: (≥18 Years): Randomized 1:1:1 Receives: Drug: imdevimab; Drug: casirivimab + imdevimab |
| Placebo | Experimental | Phase 1, Phase 2: Randomized 1:1:1:1:1 Phase 3: (≥18 Years): Randomized 1:1:1 Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Treatment Emergent Adverse Events (TEAEs)
Phase 1
Measured: Through Day 29
Severity of TEAEs
Severity was based on Grading. Grade 1 was less severe. Grade 5 was more severe.
- - Mild; Asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated
- - Moderate; Minimal, local, or noninvasive intervention indicated; limiting age appropriate instrumental activities of daily living (ADL)
- - Severe; Severe or medically significant but not immediately life threatening; hospitalization or prolongation of hospitalization indicated; disabling; ADL2 limiting self-care
- - Life-threatening; Life threatening consequences; urgent intervention indicated
- - Death; Death related to adverse events
Measured: Through Day 29
Percentage of Participants With Injection-site Reactions (ISRs)
Phase 1 only
Measured: Through Day 169
Severity of ISRs (Injection Site Reactions)
Severity was based on Grading. Grade 1 was less severe. Grade 5 was more severe.
Grade 1 - Tenderness with or without associated symptoms (eg, warmth, erythema, itching) Grade 2 - Pain; lipodystrophy; edema; phlebitis Grade 3 - Ulceration or necrosis; severe tissue damage; operative intervention indicated Grade 4 - Life-threatening consequences; urgent intervention indicated Grade 5 - Death
Measured: Through Day 29
Percentage of Participants With Hypersensitivity Reactions
Phase 1
Measured: Through Day 169
Severity of Hypersensitivity Reactions Over Time
Grade 1 - Systemic intervention not indicated. Grade 2 - Oral intervention indicated Grade 3 - Bronchospasm; hospitalization indicated for clinical sequelae; intravenous intervention indicated Grade 4 - Life-threatening consequences; urgent intervention indicated Grade 5 - Death
Measured: Through Day 169
Time-weighted Average (TWA) Daily Change From Baseline in Viral Load (log10 Copies/mL)
Phase 1 Measured by SARS-CoV-2 quantitative reverse transcription polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples
Measured: Day 1 to day 7
Secondary outcomes (18)
Percentage of Participants With Treatment-emergent Serious Adverse Events (SAEs)
Phase 1
Measured: Through Day 169
TEAEs (Treatment-Emergent Adverse Events)
Phase 2 and Phase 3
Measured: Through Day 29
Severity of TEAEs (Treatment-Emergent Adverse Event)
Phase 2 and Phase 3
Measured: Through Day 29
Percentage of Participants With ISRs (Injection-Site Reactions)
Phase 2 and Phase 3
Measured: Through Day 169
Severity of ISRs (Injection-Site Reactions)
Phase 2 and Phase 3
Measured: Through Day 169
Percentage of Participants With Hypersensitivity Reactions
Phase 2 and Phase 3
Measured: Through Day 169
Severity of Hypersensitivity Reactions Over Time
Phase 2 and Phase 3
Measured: Through Day 169
Percentage of Participants With Treatment-emergent SAEs (Serious Adverse Events)
Phase 2 and Phase 3
Measured: Through Day 169
Time-weighted Average Change From Baseline in Viral Load
Phase 2 and Phase 3
Time-weighted average (TWA) daily change from baseline in viral load (log10 copies/mL) as measured by SARS-CoV-2 quantitative reverse transcription polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples.
Measured: Through Day 169
Change From Baseline in Viral Load (Phase 1)
Phase 1 Change from baseline in viral load (log10 copies/mL) as measured by SARS-CoV-2 quantitative reverse transcription polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples.
Measured: Through Day 7
Change From Baseline in Viral Load
Phase 2, and Phase 3 As measured by RT-qPCR in NP samples
Measured: Through Day 7
Percentage of Participants With Viral Loads Below the Limit of Detection
Phase 1, Phase 2, and Phase 3
Measured: Through Day 169
Concentrations of REGN14256 in Serum Over Time (Phase 1)
Phase 1
Measured: Through Day 169
Concentrations of REGN14256 in Serum Over Time
Phase 2 and Phase 3
Measured: Through Day 169
Concentrations of Imdevimab in Serum Over Time (Phase 1)
Phase 1
Measured: Through Day 169
Concentrations of Imdevimab in Serum Over Time
Phase 2 and Phase 3
Measured: Through Day 169
Incidence and Titer of Anti-drug Antibodies (ADA) to REGN14256 Over Time
Phase 1, Phase 2, and Phase 3
Measured: Through Day 169
Incidence and Titer of ADA to Imdevimab Over Time
Phase 1, Phase 2, and Phase 3
Measured: Through Day 169
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Oct 2021
- Study start8 Nov 2021
- Primary completion30 Jun 2022
- Study completion30 Jun 2022
Why it stopped: Sponsor Decision
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for SARS-CoV-2Studies of the same condition, open and under way.
- More trials run by Regeneron PharmaceuticalsThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Phase1/Phase2/Phase3
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Regeneron Pharmaceuticals
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Clinical Trial Management, Study director, Regeneron Pharmaceuticals
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05081388
- Sponsor's protocol ID
- R14256-COV-2149
- Status last verified
- Oct 2025
- First submitted
- 14 Oct 2021
- Last updated
- 28 Oct 2025
- Results posted
- Yes, on ClinicalTrials.gov
- 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
Study at a glance
From the registry record, last updated by the sponsor on 28 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1/2/3 Adaptive Study to Evaluate the Safety, Tolerability, and Efficacy of REGN14256+Imdevimab for the Treatment of COVID-19 Patients Without Risk Factors for Progression to Severe Disease
- ClinicalTrials.gov ID
- NCT05081388
- Acronym / sponsor ID
- R14256-COV-2149
- Conditions
- SARS-CoV-2
- Keywords
- COVID-19, Non-hospitalized, Low-risk, Symptomatic, Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), coronavirus
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Sponsor Decision
- Enrolment
- 25 participants (actual)
- Lead sponsor
- Regeneron PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 8 Nov 2021 (actual)
- Primary completion
- 30 Jun 2022 (actual)
- Study completion
- 30 Jun 2022 (actual)
- First posted
- 18 Oct 2021 (actual)
- Results
- Posted 26 Apr 2024
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Primary Objectives Phase 1 (Safety and Tolerability)
- Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by treatment-emergent adverse events (TEAEs), injection-site reactions (ISRs), and hypersensitivity reactions
Phase 1/2 (Virologic Efficacy) • Evaluate the virologic efficacy of REGN14256+imdevimab and REGN14256 monotherapy compared to placebo, as measured by time-weighted average (TWA) change from baseline in viral load through day 7
Phase 1/2/3 (Clinical Efficacy)
- Evaluate the clinical efficacy of REGN14256+imdevimab compared to placebo, as measured by COVID-19 symptoms resolution
Secondary Objectives Phase 1 (Safety and Tolerability) • Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by treatment-emergent serious adverse events (SAEs)
Phase 2 and Phase 3 (Safety and Tolerability)
- Evaluate the safety and tolerability of REGN14256+imdevimab and REGN14256 monotherapy, as measured by TEAEs, ISRs, hypersensitivity reactions, and SAEs
Phase 1, Phase 2, and Phase 3 (Virologic Efficacy, Drug Concentration, and Immunogenicity)
- Evaluate additional indicators of virologic efficacy of REGN14256+imdevimab and REGN14256 monotherapy
- Characterize the concentration-time profile of REGN14256 administered in combination with imdevimab or alone as a monotherapy
- Assess the immunogenicity of REGN14256 administered in combination with imdevimab or alone as a monotherapy
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 5
- Model description
- Phase1/Phase2/Phase3
| Arm | Type | Receives |
|---|---|---|
| REGN14256 + imdevimab | Experimental | Drug: REGN14256, Drug: imdevimabPhase 1, Phase 2: Randomized 1:1:1:1:1 Phase 3: (≥18 Years): Randomized 1:1:1 Phase 3: (Open label) (≥12 and <18 Years) |
| REGN14256 | Experimental | Drug: REGN14256Phase 1, Phase 2: Randomized 1:1:1:1:1 |
| Imdevimab | Experimental | Drug: imdevimabPhase 1, Phase 2: Randomized 1:1:1:1:1 |
| casirivimab + imdevimab | Experimental | Drug: imdevimab, Drug: casirivimab + imdevimabPhase 1, Phase 2: Randomized 1:1:1:1:1 Phase 3: (≥18 Years): Randomized 1:1:1 |
| Placebo | Experimental | Drug: PlaceboPhase 1, Phase 2: Randomized 1:1:1:1:1 Phase 3: (≥18 Years): Randomized 1:1:1 |
Who may qualify
- Ages
- 12 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (4 listed)
- For the adolescent cohort in Phase 3 only: Weighs ≥40 kg at randomization
- Has SARS-CoV-2-positive antigen or molecular diagnostic test (by validated SARSCoV-2 antigen, RT-PCR, or other molecular diagnostic assay, using an appropriate sample such as nasopharyngeal [NP], nasal, oropharyngeal [OP], or saliva) ≤72 hours prior to randomization. A historical record of a positive result is acceptable as long as the sample was collected ≤72 hours prior to randomization
- Has symptoms consistent with COVID-19 (as determined by the investigator) with onset ≤7 days before randomization, and doesn't have a medical condition or other factors associated with high risk for progression to severe COVID-19 as outlined in the exclusion criteria
- Maintains O2 saturation ≥93% on room air
Key exclusion criteria (27 listed)
- Has a medical condition or other factors associated with high risk for progression to severe COVID-19:
- Prior, current (at randomization) or planned use (within time period given per CDC guidance [90 days]) of any authorized or approved vaccine for COVID-19
- Was admitted to a hospital for COVID-19 prior to randomization, or is hospitalized (inpatient) for any reason at randomization
- Has a known prior SARS-CoV-2 infection or positive SARS-CoV-2 serologic test
- Has a positive SARS-CoV-2 antigen or molecular diagnostic test from a sample collected >72 hours prior to randomization
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| REGN14256Sub-cutaneous (SC) single dose | Drug | REGN14256, REGN14256 + imdevimab |
| imdevimabAlso: REGN10987SC single dose | Drug | Imdevimab, REGN14256 + imdevimab, casirivimab + imdevimab |
| casirivimab + imdevimabAlso: REGN10933 + REGN10987, REGN-COV2, REGEN-COV™, Ronapreve™SC single dose | Drug | casirivimab + imdevimab |
| PlaceboSC single dose | Drug | Placebo |
Primary outcome
Treatment Emergent Adverse Events (TEAEs)
Time frame: Through Day 29
Phase 1
Severity of TEAEs
Time frame: Through Day 29
Severity was based on Grading. Grade 1 was less severe. Grade 5 was more severe. 1. - Mild; Asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated 2. - Moderate; Minimal, local, or noninvasive intervention indicated; limiting age appropriate instrumental activities of daily living (ADL) 3. - Severe; Severe or medically significant but not immediately life threatening; hospitalization or prolongation of hospitalization indicated; disabling; ADL2 limiting self-care 4. - Life-threatening; Life threatening consequences; urgent intervention indicated 5. - Death; Death related to adverse events
Percentage of Participants With Injection-site Reactions (ISRs)
Time frame: Through Day 169
Phase 1 only
Severity of ISRs (Injection Site Reactions)
Time frame: Through Day 29
Severity was based on Grading. Grade 1 was less severe. Grade 5 was more severe. Grade 1 - Tenderness with or without associated symptoms (eg, warmth, erythema, itching) Grade 2 - Pain; lipodystrophy; edema; phlebitis Grade 3 - Ulceration or necrosis; severe tissue damage; operative intervention indicated Grade 4 - Life-threatening consequences; urgent intervention indicated Grade 5 - Death
Percentage of Participants With Hypersensitivity Reactions
Time frame: Through Day 169
Phase 1
Severity of Hypersensitivity Reactions Over Time
Time frame: Through Day 169
Grade 1 - Systemic intervention not indicated. Grade 2 - Oral intervention indicated Grade 3 - Bronchospasm; hospitalization indicated for clinical sequelae; intravenous intervention indicated Grade 4 - Life-threatening consequences; urgent intervention indicated Grade 5 - Death
Time-weighted Average (TWA) Daily Change From Baseline in Viral Load (log10 Copies/mL)
Time frame: Day 1 to day 7
Phase 1 Measured by SARS-CoV-2 quantitative reverse transcription polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples
18 secondary outcomes
Percentage of Participants With Treatment-emergent Serious Adverse Events (SAEs)
Time frame: Through Day 169
TEAEs (Treatment-Emergent Adverse Events)
Time frame: Through Day 29
Severity of TEAEs (Treatment-Emergent Adverse Event)
Time frame: Through Day 29
Percentage of Participants With ISRs (Injection-Site Reactions)
Time frame: Through Day 169
Severity of ISRs (Injection-Site Reactions)
Time frame: Through Day 169
Percentage of Participants With Hypersensitivity Reactions
Time frame: Through Day 169
Severity of Hypersensitivity Reactions Over Time
Time frame: Through Day 169
Percentage of Participants With Treatment-emergent SAEs (Serious Adverse Events)
Time frame: Through Day 169
Time-weighted Average Change From Baseline in Viral Load
Time frame: Through Day 169
Change From Baseline in Viral Load (Phase 1)
Time frame: Through Day 7
Change From Baseline in Viral Load
Time frame: Through Day 7
Percentage of Participants With Viral Loads Below the Limit of Detection
Time frame: Through Day 169
Concentrations of REGN14256 in Serum Over Time (Phase 1)
Time frame: Through Day 169
Concentrations of REGN14256 in Serum Over Time
Time frame: Through Day 169
Concentrations of Imdevimab in Serum Over Time (Phase 1)
Time frame: Through Day 169
Concentrations of Imdevimab in Serum Over Time
Time frame: Through Day 169
Incidence and Titer of Anti-drug Antibodies (ADA) to REGN14256 Over Time
Time frame: Through Day 169
Incidence and Titer of ADA to Imdevimab Over Time
Time frame: Through Day 169
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Oct 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: Yes. All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Clinical Trial Management study director
Regeneron Pharmaceuticals
28 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing REGN14256, imdevimab and casirivimab + imdevimab in people with SARS-CoV-2, run by Regeneron Pharmaceuticals at 28 sites in United States.
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 4 inclusion and 27 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 28 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 28 sites in United States. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
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 26 Apr 2024). 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?
Treatment Emergent Adverse Events (TEAEs) (time frame: Through Day 29). The study lists 7 primary outcomes in all. 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 28 Oct 2025.