Healthy VolunteersPhase 1NCT05102136
Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of REGN9933 in Adult Healthy Volunteers
A Phase 1 study testing REGN9933 in people with Healthy Volunteers, run by Regeneron Pharmaceuticals at 1 site in Belgium.
Trial summary
The primary objective of the study is to evaluate the safety and tolerability of single doses of REGN9933 in healthy participants The secondary objectives of the study are to: Evaluate the effects of single doses of REGN9933 on intrinsic/common pathway coagulation Evaluate the effects of single doses of REGN9933 on… Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Volunteers
- What is being tested?
- REGN9933
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 56 participants
- Where
- 1 siteBelgium
- Study dates
- 27 Oct 2021to 4 Apr 2023
- Phase
- Phase 1
- Are there results?
- None posted in the registry
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 18 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Body mass index between 18.0 and 32.5 kilograms/per metered squared (kg/m^2) (inclusive) at the screening visit.
- Judged by the investigator to be in good health based on medical history, physical examination, vital sign measurements, and electrocardiogram (ECGs) performed at screening and/or prior to administration of initial dose of study drug.
- Participant is in good health based on laboratory safety testing obtained at the screening visit and/or prior to administration of initial dose of study drug. Note :Participant with suspected or confirmed Gilbert's disease can be enrolled in the study.
- Normal activated partial thromboplastin time (aPTT), normal prothrombin time (PT), and normal platelet counts at screening period and at day -1 as defined by the local laboratory
- Hemoglobin value ≥11.0 grams per deciliter (g/dL) for females and ≥12.9 g/dL for males at screening and day -1
- Negative fecal occult blood test (FOBT) during screening period
- Normal Bleeding time test (BTT) at day -1 as defined by the study site
Who cannot join
- History of any major surgical procedure or clinically significant physical trauma, in the opinion of the investigator, that may pose a risk to the subject by study participation.
- Whole blood donation within the previous 56 days or plasma donation within the previous 7 days prior to screening
- Pregnant or breastfeeding women
- History of clinically significant cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, psychiatric, neurological, or dermatologic disease, as assessed by the investigator
- Hospitalized for any reason within 30 days of the screening visit.
- Current smoker or former smoker, including e-cigarettes, who stopped smoking within 12 months prior to the screening visit
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- Confirmed positive drug test result at the screening visit and/or prior to randomization or a history of drug abuse within a year prior to screening.
- History of alcohol abuse within the last 2 years prior to dosing
- Positive for human immunodeficiency virus (HIV), hepatitis B, or and/or hepatitis C per protocol resolved hepatitis B infection is not an exclusion.
- Any malignancy, except for nonmelanoma skin cancer or cervical/anus in situ, that have been resected with no evidence of metastatic disease for 3 years prior to the screening visit
- Women of child bearing potential (defined as women who are fertile, following menarche until becoming postmenopausal, unless permanently surgically sterile. The only allowed permanent sterilization methods for this study are hysterectomy and/or bilateral oophorectomy.)
- Note: Other protocol defined inclusion/exclusion criteria apply.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single-Center Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single Ascending Doses of REGN9933, a Monoclonal Antibody Against Factor XI, in Healthy Adult Subjects
The primary objective of the study is to evaluate the safety and tolerability of single doses of REGN9933 in healthy participants
The secondary objectives of the study are to:
- Evaluate the effects of single doses of REGN9933 on intrinsic/common pathway coagulation
- Evaluate the effects of single doses of REGN9933 on extrinsic/common pathway coagulation
- Characterize the drug concentration profiles and pharmacokinetic (PK) following single escalating doses of REGN9933
- Characterize the concentration profiles of total FXI following single escalating doses of REGN9933
- Assess the immunogenicity of single doses of REGN9933
- Conditions
- Healthy Volunteers
- Being tested
- REGN9933, Placebo
- Keywords
- HV
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
REGN9933Drug
Administered intravenously (IV) or subcutaneous (SC) per the protocol
PlaceboDrug
Placebo to match REGN9933 in same form; placebo administered IV or SC per the protocol
| Study group | Role | What they receive |
|---|---|---|
| Intravenous Cohorts | Experimental | Randomized 6:2 to REGN9933 or placebo Receives: Drug: REGN9933; Drug: Placebo |
| Subcutaneous Cohorts | Experimental | Randomized 6:2 to REGN9933 or placebo Receives: Drug: REGN9933; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence and severity of treatment emergent adverse events (TEAE)
Measured: Until resolution of pharmacodynamic (PD) effects; approximately 36 days
Secondary outcomes (5)
Change from baseline in activated partial thromboplastin time (aPTT)
Measured: Until resolution of PD effects; approximately 36 days
Change from baseline in prothrombin time (PT)
Measured: Until resolution of PD effects; approximately 36 days
Concentration of REGN9933 in serum
Measured: Until resolution of PD effects; approximately 36 days
Change from baseline in total Factor XI (FXI) concentrations
Measured: Until resolution of PD effects; approximately 36 days
The incidence of antidrug antibodies (ADAs) to REGN9933 over time
Measured: Until resolution of PD effects; approximately 36 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Nov 2021
- Study start27 Oct 2021
- Primary completion4 Apr 2023
- Study completion4 Apr 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Healthy VolunteersStudies 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
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 56 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
- NCT05102136
- Sponsor's protocol ID
- R9933-HV-2107
- Other IDs
- 2021-002568-34
- Status last verified
- Apr 2023
- First submitted
- 19 Oct 2021
- Last updated
- 3 May 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
Publications
Chalothorn D, Kithcart AP, Marin E, Somersan-Karakaya S, Lai K, Cauwberghs F, Ackroyd JPR, Mohammadi K, Shrestha A, Ehrlich GK, Rafique A, Chatterjee I, Saotome K, Franklin MC, Murphy AJ, Olson WC, Olenchock BA, Herman GA, Gutstein DE, Sirulnik A, Yancopoulos GD, Morton LG. Anticoagulation with mechanistically distinct FXI/FXIa antibodies amrecibart (REGN9933A2) and cenvacibart (REGN7508Cat). Blood. 2026 Jun 11:blood.2025032276. doi: 10.1182/blood.2025032276. Online ahead of print.
PubMed 42275249
Study at a glance
From the registry record, last updated by the sponsor on 3 May 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single-Center Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single Ascending Doses of REGN9933, a Monoclonal Antibody Against Factor XI, in Healthy Adult Subjects
- ClinicalTrials.gov ID
- NCT05102136
- Acronym / sponsor ID
- R9933-HV-2107
- Conditions
- Healthy Volunteers
- Keywords
- HV
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 56 participants (actual)
- Lead sponsor
- Regeneron PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 27 Oct 2021 (actual)
- Primary completion
- 4 Apr 2023 (actual)
- Study completion
- 4 Apr 2023 (actual)
- First posted
- 1 Nov 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary objective of the study is to evaluate the safety and tolerability of single doses of REGN9933 in healthy participants
The secondary objectives of the study are to:
- Evaluate the effects of single doses of REGN9933 on intrinsic/common pathway coagulation
- Evaluate the effects of single doses of REGN9933 on extrinsic/common pathway coagulation
- Characterize the drug concentration profiles and pharmacokinetic (PK) following single escalating doses of REGN9933
- Characterize the concentration profiles of total FXI following single escalating doses of REGN9933
- Assess the immunogenicity of single doses of REGN9933
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Intravenous Cohorts | Experimental | Drug: REGN9933, Drug: PlaceboRandomized 6:2 to REGN9933 or placebo |
| Subcutaneous Cohorts | Experimental | Drug: REGN9933, Drug: PlaceboRandomized 6:2 to REGN9933 or placebo |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Body mass index between 18.0 and 32.5 kilograms/per metered squared (kg/m^2) (inclusive) at the screening visit.
- Judged by the investigator to be in good health based on medical history, physical examination, vital sign measurements, and electrocardiogram (ECGs) performed at screening and/or prior to administration of initial dose of study drug.
- Participant is in good health based on laboratory safety testing obtained at the screening visit and/or prior to administration of initial dose of study drug. Note :Participant with suspected or confirmed Gilbert's disease can be enrolled in the study.
- Normal activated partial thromboplastin time (aPTT), normal prothrombin time (PT), and normal platelet counts at screening period and at day -1 as defined by the local laboratory
- Hemoglobin value ≥11.0 grams per deciliter (g/dL) for females and ≥12.9 g/dL for males at screening and day -1
Key exclusion criteria (12 listed)
- History of any major surgical procedure or clinically significant physical trauma, in the opinion of the investigator, that may pose a risk to the subject by study participation.
- Whole blood donation within the previous 56 days or plasma donation within the previous 7 days prior to screening
- Pregnant or breastfeeding women
- History of clinically significant cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, psychiatric, neurological, or dermatologic disease, as assessed by the investigator
- Hospitalized for any reason within 30 days of the screening visit.
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 |
|---|---|---|
| REGN9933Administered intravenously (IV) or subcutaneous (SC) per the protocol | Drug | Intravenous Cohorts, Subcutaneous Cohorts |
| PlaceboPlacebo to match REGN9933 in same form; placebo administered IV or SC per the protocol | Drug | Intravenous Cohorts, Subcutaneous Cohorts |
Primary outcome
Incidence and severity of treatment emergent adverse events (TEAE)
Time frame: Until resolution of pharmacodynamic (PD) effects; approximately 36 days
5 secondary outcomes
Change from baseline in activated partial thromboplastin time (aPTT)
Time frame: Until resolution of PD effects; approximately 36 days
Change from baseline in prothrombin time (PT)
Time frame: Until resolution of PD effects; approximately 36 days
Concentration of REGN9933 in serum
Time frame: Until resolution of PD effects; approximately 36 days
Change from baseline in total Factor XI (FXI) concentrations
Time frame: Until resolution of PD effects; approximately 36 days
The incidence of antidrug antibodies (ADAs) to REGN9933 over time
Time frame: Until resolution of PD effects; approximately 36 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 May 2023.
- Derived from this study: PubMed 42275249Chalothorn D, Kithcart AP, Marin E, Somersan-Karakaya S, Lai K, Cauwberghs F, Ackroyd JPR, Mohammadi K, Shrestha A, Ehrlich GK, Rafique A, Chatterjee I, Saotome K, Franklin MC, Murphy AJ, Olson WC, Olenchock BA, Herman GA, Gutstein DE, Sirulnik A, Yancopoulos GD, Morton LG. Anticoagulation with mechanistically distinct FXI/FXIa antibodies amrecibart (REGN9933A2) and cenvacibart (REGN7508Cat). Blood. 2026 Jun 11:blood.2025032276. doi: 10.1182/blood.2025032276. Online ahead of print.
- Individual participant dataSharing planned: Yes. All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
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Screening Protocol
Pain
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
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing REGN9933 in people with Healthy Volunteers, run by Regeneron Pharmaceuticals at 1 site in Belgium.
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 7 inclusion and 12 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: finished, as of the sponsor's last update on 3 May 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. 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 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.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Incidence and severity of treatment emergent adverse events (TEAE) (time frame: Until resolution of pharmacodynamic (PD) effects; approximately 36 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05102136, which also lists 1 linked publication.
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 3 May 2023.