Uncontrolled HypertensionPhase 2NATRIX-SBPNCT06833190
REGN5381 in Adult Participants With Uncontrolled Hypertension
A Phase 2 study testing REGN5381 in people with Uncontrolled Hypertension, run by Regeneron Pharmaceuticals at 3 sites in United Kingdom.
Trial summary
This study is researching an experimental drug called REGN5381 (called "study drug"). The study is focused on uncontrolled hypertension (high blood pressure despite being on one or more antihypertensive drugs). The aim of the study is to see how effective the study drug is in reducing blood pressure. Read more about this study
- Who is it for?
- Ages 30 to 85 years
- Conditions the study is for
- Uncontrolled Hypertension
- What is being tested?
- REGN5381
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 34 participants
- Where
- 3 sitesUnited Kingdom
- Study dates
- 16 Apr 2025to 15 Oct 2025
- Phase
- Phase 2
- 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 30 to 85 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults with SBP ≥130 mm Hg and SBP ≤180 mm Hg at both screening and randomization visit, as described in the protocol
- ≥ 40 and ≤85 years on a stable regimen of ≥1 anti-hypertensive therapy for at least 1 month at the time of screening or ≥30 and <40 years on a stable regimen of ≥3 anti-hypertensive therapies for at least 1 month at the time of screening
Who cannot join
- Heart rate >100 bpm as described in the protocol
- Body mass index >45 kg/m2 as described in the protocol
- Glomerular filtration rate (GFR) <30 mL/min/1.73m2 at screening as described in the protocol
- Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) ≥3x upper limit of normal (ULN) as described in the protocol
- NOTE: Other protocol-defined Inclusion/Exclusion Criteria apply
Trial locations and contacts
3 sites in 1 country.
United Kingdom3 sites
Protas, Car Park of Asda Pilsworth Road
Bury, BL9 8RS
Protas, Car Park of Asda Huyton Supercentre
Huyton, Liverpool, L36 7TX
Protas, Two New Bailey Square
Salford, Manchester, M3 5GS
About this study
Official title: A Phase 2b, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of a Multiple Dose Regimen of REGN5381, an NPR1 Monoclonal Antibody Agonist, in Participants With Uncontrolled Hypertension
This study is researching an experimental drug called REGN5381 (called "study drug"). The study is focused on uncontrolled hypertension (high blood pressure despite being on one or more antihypertensive drugs).
The aim of the study is to see how effective the study drug is in reducing blood pressure. The study is designed as a 2-part study with participants initially enrolling in Part A. Part B of the study will commence and enroll the remaining study participants.
Read more
The study is looking at several other research questions, including:
- What side effects may happen from taking the study drug
- How much study drug is in the blood at different times
- Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)
Read the detailed description
As of October 15, 2025, this study has been terminated, and all future onsite visits have been canceled. However, participants have been asked to report safety information to the trial helpline until January 15, 2026.
- Conditions
- Uncontrolled Hypertension
- Being tested
- REGN5381, Placebo
- Keywords
- High blood pressure, Systolic Blood Pressure (SBP)
- Medical subject headings
- Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
REGN5381Drug
Administered per the protocol
PlaceboDrug
Administered per the protocol
| Study group | Role | What they receive |
|---|---|---|
| REGN5381 Low Dose | Experimental | Randomized as described in the protocol Receives: Drug: REGN5381 |
| REGN5381 High Dose | Experimental | Randomized as described in the protocol Receives: Drug: REGN5381 |
| Placebo | Placebo comparator | Randomized as described in the protocol Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Unattended Automated Office-Based Blood Pressure (AOBP) Systolic Blood Pressure (SBP)
Measured: At week 12
Secondary outcomes (13)
Unattended AOBP SBP in stage 3 Chronic Kidney Disease (CKD) participants
Measured: At week 12
Unattended AOBP SBP in participants on ≥3 anti-hypertensive therapies
Measured: At week 12
Time-weighted average AOBP SBP
Measured: Through week 12
Time-weighted average AOBP Diastolic Blood Pressure (DBP)
Measured: Through week 12
AOBP SBP
Measured: From baseline to weeks 2, 4 and 8
AOBP DBP
Measured: From baseline to weeks 2, 4, 8 and 12
Mean SBP by 24-hour Ambulatory Blood Pressure Monitoring (ABPM)
Measured: At week 12
Concentrations of REGN5381 in serum
Measured: Through week 20
Occurrence of Treatment Emergent Adverse Events (TEAEs)
Measured: Up to week 23
Severity of TEAEs
Measured: Up to week 23
Occurrence of TEAEs leading to discontinuation of study drug
Measured: Up to week 23
Occurrence of Anti-Drug Antibodies (ADAs) to REGN5381
Measured: Through week 20
Titer of ADAs to REGN5381
Measured: Through week 20
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Feb 2025
- Study start16 Apr 2025
- Primary completion15 Oct 2025
- Study completion15 Oct 2025
Why it stopped: Sponsor decision
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Uncontrolled HypertensionStudies 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 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 34 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
- NCT06833190
- Sponsor's protocol ID
- R5381-UHTN-2410
- Acronym
- NATRIX-SBP
- Status last verified
- Oct 2025
- First submitted
- 12 Feb 2025
- Last updated
- 23 Oct 2025
- Results posted
- No
- 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 23 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2b, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of a Multiple Dose Regimen of REGN5381, an NPR1 Monoclonal Antibody Agonist, in Participants With Uncontrolled Hypertension
- ClinicalTrials.gov ID
- NCT06833190
- Acronym / sponsor ID
- NATRIX-SBP / R5381-UHTN-2410
- Conditions
- Uncontrolled Hypertension
- Keywords
- High blood pressure, Systolic Blood Pressure (SBP)
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Sponsor decision
- Enrolment
- 34 participants (actual)
- Lead sponsor
- Regeneron PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 16 Apr 2025 (actual)
- Primary completion
- 15 Oct 2025 (actual)
- Study completion
- 15 Oct 2025 (actual)
- First posted
- 18 Feb 2025 (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.
This study is researching an experimental drug called REGN5381 (called "study drug"). The study is focused on uncontrolled hypertension (high blood pressure despite being on one or more antihypertensive drugs).
The aim of the study is to see how effective the study drug is in reducing blood pressure. The study is designed as a 2-part study with participants initially enrolling in Part A. Part B of the study will commence and enroll the remaining study participants.
The study is looking at several other research questions, including:
- What side effects may happen from taking the study drug
- How much study drug is in the blood at different times
- Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)
Detailed description
As of October 15, 2025, this study has been terminated, and all future onsite visits have been canceled. However, participants have been asked to report safety information to the trial helpline until January 15, 2026.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| REGN5381 Low Dose | Experimental | Drug: REGN5381Randomized as described in the protocol |
| REGN5381 High Dose | Experimental | Drug: REGN5381Randomized as described in the protocol |
| Placebo | Placebo comparator | Drug: PlaceboRandomized as described in the protocol |
Who may qualify
- Ages
- 30 to 85 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Adults with SBP ≥130 mm Hg and SBP ≤180 mm Hg at both screening and randomization visit, as described in the protocol
- ≥ 40 and ≤85 years on a stable regimen of ≥1 anti-hypertensive therapy for at least 1 month at the time of screening or ≥30 and <40 years on a stable regimen of ≥3 anti-hypertensive therapies for at least 1 month at the time of screening
Key exclusion criteria (5 listed)
- Heart rate >100 bpm as described in the protocol
- Body mass index >45 kg/m2 as described in the protocol
- Glomerular filtration rate (GFR) <30 mL/min/1.73m2 at screening as described in the protocol
- Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) ≥3x upper limit of normal (ULN) as described in the protocol
- NOTE: Other protocol-defined Inclusion/Exclusion Criteria apply
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 |
|---|---|---|
| REGN5381Administered per the protocol | Drug | REGN5381 High Dose, REGN5381 Low Dose |
| PlaceboAdministered per the protocol | Drug | Placebo |
Primary outcome
Unattended Automated Office-Based Blood Pressure (AOBP) Systolic Blood Pressure (SBP)
Time frame: At week 12
13 secondary outcomes
Unattended AOBP SBP in stage 3 Chronic Kidney Disease (CKD) participants
Time frame: At week 12
Unattended AOBP SBP in participants on ≥3 anti-hypertensive therapies
Time frame: At week 12
Time-weighted average AOBP SBP
Time frame: Through week 12
Time-weighted average AOBP Diastolic Blood Pressure (DBP)
Time frame: Through week 12
AOBP SBP
Time frame: From baseline to weeks 2, 4 and 8
AOBP DBP
Time frame: From baseline to weeks 2, 4, 8 and 12
Mean SBP by 24-hour Ambulatory Blood Pressure Monitoring (ABPM)
Time frame: At week 12
Concentrations of REGN5381 in serum
Time frame: Through week 20
Occurrence of Treatment Emergent Adverse Events (TEAEs)
Time frame: Up to week 23
Severity of TEAEs
Time frame: Up to week 23
Occurrence of TEAEs leading to discontinuation of study drug
Time frame: Up to week 23
Occurrence of Anti-Drug Antibodies (ADAs) to REGN5381
Time frame: Through week 20
Titer of ADAs to REGN5381
Time frame: Through week 20
Results and safety
The study was stopped early (reason given: Sponsor decision). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Oct 2025.
- 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
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing REGN5381 in people with Uncontrolled Hypertension, run by Regeneron Pharmaceuticals at 3 sites in United Kingdom.
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 2 inclusion and 5 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 23 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 3 sites in United Kingdom. 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 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?
The study was stopped early (reason given: Sponsor decision). Results are not available in the source record.
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?
Unattended Automated Office-Based Blood Pressure (AOBP) Systolic Blood Pressure (SBP) (time frame: At week 12). 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 23 Oct 2025.