Pulmonary Arterial HypertensionPhase 1/2NCT07143448
A Study of HS235 for Treatment of Pulmonary Arterial Hypertension (PAH) in Adults
A Phase 1/2 study testing HS235 in people with Pulmonary Arterial Hypertension, run by 35Pharma Inc., a GSK company at 7 sites in 3 countries.
Trial summary
Phase 1b/2 Study of HS235 Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of the Activin Signaling Inhibitor HS235 Added to Background Treatment in Adults with Pulmonary Arterial Hypertension (PAH) Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Pulmonary Arterial Hypertension
- What is being tested?
- HS235
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 90 participants
- Where
- 7 sitesin 3 countries
- Study dates
- 19 Aug 2026to Nov 2028
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Participants are eligible to be included in the study only if they meet all of the following criteria:
- Male and female participants, 18 years of age and older.
- Body Mass Index (BMI) 18.5 and 40 kg/m2 and body weight at or below 120 kg.
- Baseline RHC performed during the Screening Period documenting:
- A minimum PVR of ≥ 5 Wood units (WU) or ≥ 400 dyn·sec·cm-5 and,
- A pulmonary artery wedge pressure (PAWP) of ≤ 15 mm Hg.
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- Diagnosis of WHO pulmonary arterial hypertension (PAH) Group 1.
- Symptomatic PAH classified as WHO Functional class II to IV.
- On stable doses of at least 2 approved background PAH therapies and diuretics.
- 6-Minute Walk Distance (6MWD) ≥ 150 m and ≤ 500 m repeated twice during screening.
- Ability to adhere to study visit schedule and understand and comply with all protocol requirements.
Who cannot join
- PH WHO Groups 2, 3, 4 or 5.
- Hospitalization for any worsening medical condition or major surgery within 4 weeks prior to screening.
- Any symptomatic coronary disease events.
- History of heart transplant or on heart transplant list.
- Uncontrolled systemic hypertension.
- History of restrictive, constrictive or congestive cardiomyopathy.
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- History of significant mitral regurgitation or aortic regurgitation valvular disease.
- Untreated or poorly controlled moderate or severe obstructive sleep apnea.
- A diagnosis of worse than moderate COPD or worse than mild ILD.
- Cerebrovascular event within 90 days prior to screening
- A pneumonectomy or lobectomy
- Having received an activin signaling inhibitor such as sotatercept at any time prior to screening
- A Hgb > sex-specific ULN
- Platelets count < 100,000/mm3
- Severe (stage ≥4) renal failure with eGFR < 30 mL/min/m2
- Abnormally elevated liver function enzymes (ALT or AST > 3X ULN, or total bilirubin > 1.5X ULN).
Trial locations and contacts
7 sites in 3 countries. Contact the study team or a site near you to ask about taking part.
7 sites in 3 countries
United States3 sites, 3 recruiting
- Recruiting
Investigational Site-101
Boston, Massachusetts, 02115-6105
- Recruiting
Investigational Site-104
Providence, Rhode Island, 02903
- Recruiting
Investigational Site-102
Tampa, Florida, 33620
Spain3 sites, 3 recruiting
- Recruiting
Investigational Site-305
Barcelona, 08035
- Recruiting
Investigational Site- 301
Barcelona, 8036
- Recruiting
Investigational Site-308
Madrid, 28041
United Kingdom1 site, 1 recruiting
- Recruiting
Investigational Site-903
London, W12 0HS
About this study
Official title: Phase 1b/2, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Study Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of HS235 Added to Background Treatment in Adults With PAH
Phase 1b/2 Study of HS235 Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of the Activin Signaling Inhibitor HS235 Added to Background Treatment in Adults with Pulmonary Arterial Hypertension (PAH)
Read the detailed description
A Phase 1b/2, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Study Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of the Activin Signaling Inhibitor HS235 Added to Background Treatment in Adults with Pulmonary Arterial Hypertension (PAH)
- Conditions
- Pulmonary Arterial Hypertension
- Being tested
- HS235, Placebo
- Medical subject headings
- Pulmonary Arterial Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HS235Biological
Subcutaneous Injection
PlaceboOther
Subcutaneous Injection
| Study group | Role | What they receive |
|---|---|---|
| HS235 | Experimental | HS235 Subcutaneous Injection Receives: Biological: HS235 |
| Placebo | Placebo comparator | Subcutaneous Injection Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence and Number of Adverse Events (AEs)
An AE is any untoward medical occurrence in a participants or clinical trial participants administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment. The incidence and number of participants who experience an AE will be reported.
Measured: up to 29 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Aug 2025
- Study start19 Aug 2026
- Primary completionMar 2028 (estimated)
- Study completionNov 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pulmonary Arterial HypertensionStudies of the same condition, open and under way.
- 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
- Sequential
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 90 participants (estimated)
Sponsor and investigators
- Lead sponsor
- 35Pharma Inc., a GSK company
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07143448
- Sponsor's protocol ID
- HS235-002
- Status last verified
- Sep 2026
- First submitted
- 20 Aug 2025
- Last updated
- 30 Oct 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 30 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Phase 1b/2, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Study Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of HS235 Added to Background Treatment in Adults With PAH
- ClinicalTrials.gov ID
- NCT07143448
- Acronym / sponsor ID
- HS235-002
- Conditions
- Pulmonary Arterial Hypertension
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 90 participants (estimated)
- Lead sponsor
- 35Pharma Inc., a GSK companyIndustry (pharma, biotech, devices)
- Study start
- 19 Aug 2026 (actual)
- Primary completion
- Mar 2028 (estimated)
- Study completion
- Nov 2028 (estimated)
- First posted
- 27 Aug 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.
Phase 1b/2 Study of HS235 Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of the Activin Signaling Inhibitor HS235 Added to Background Treatment in Adults with Pulmonary Arterial Hypertension (PAH)
Detailed description
A Phase 1b/2, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Study Assessing the Safety, Pharmacokinetics, Pharmacodynamics, and Efficacy of the Activin Signaling Inhibitor HS235 Added to Background Treatment in Adults with Pulmonary Arterial Hypertension (PAH)
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| HS235 | Experimental | Biological: HS235HS235 Subcutaneous Injection |
| Placebo | Placebo comparator | Other: PlaceboSubcutaneous Injection |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (11 listed)
- Participants are eligible to be included in the study only if they meet all of the following criteria:
- Male and female participants, 18 years of age and older.
- Body Mass Index (BMI) 18.5 and 40 kg/m2 and body weight at or below 120 kg.
- Baseline RHC performed during the Screening Period documenting:
- Diagnosis of WHO pulmonary arterial hypertension (PAH) Group 1.
Key exclusion criteria (16 listed)
- PH WHO Groups 2, 3, 4 or 5.
- Hospitalization for any worsening medical condition or major surgery within 4 weeks prior to screening.
- Any symptomatic coronary disease events.
- History of heart transplant or on heart transplant list.
- Uncontrolled systemic hypertension.
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 |
|---|---|---|
| HS235Subcutaneous Injection | Biological | HS235 |
| PlaceboSubcutaneous Injection | Other | Placebo |
Primary outcome
Incidence and Number of Adverse Events (AEs)
Time frame: up to 29 weeks
An AE is any untoward medical occurrence in a participants or clinical trial participants administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment. The incidence and number of participants who experience an AE will be reported.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Oct 2026.
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A Pilot Study of Microbiota Transplant With Antibiotic Preconditioning and Fiber Supplementation in Pulmonary Arterial Hypertension (GUT RESTORE-PAH)
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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.
7 sites in 3 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing HS235 in people with Pulmonary Arterial Hypertension, run by 35Pharma Inc., a GSK company at 7 sites in 3 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 11 inclusion and 16 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: looking for participants now, as of the sponsor's last update on 30 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 7 sites in United States, Spain, 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 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact US GSK Clinical Trials Call Center (877-379-3718, GSKClinicalSupportHD@gsk.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence and Number of Adverse Events (AEs) (time frame: up to 29 weeks). 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 30 Oct 2026.