A Phase 2 interventional study of REGN13335 and Placebo in Pulmonary Arterial Hypertension (PAH), sponsored by Regeneron Pharmaceuticals. Recruiting at 33 sites in 10 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-26.
Sponsored by Regeneron Pharmaceuticals · Phase 2, Interventional, and Treatment
This study is researching an experimental drug called REGN13335. The study is focused on participants with Pulmonary Arterial Hypertension (PAH). The aim of the study is to see how safe and effective REGN13335 is in participants with PAH who are taking other PAH medicines.
The study is looking at several other research questions, including:
699 studies on the registry are indexed under Pulmonary Arterial Hypertension; 140 are open to participants now.
This study's planned enrollment of 99 is above the median of 40 across 477 interventional studies indexed under Pulmonary Arterial Hypertension.
Browse Pulmonary Arterial Hypertension studies →Regeneron Pharmaceuticals is the lead sponsor of 411 studies on the registry; 90 are open to participants now.
Of its 125 completed or terminated interventional studies of FDA-regulated products, 79 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Note: Other protocol-defined Inclusion/ Exclusion criteria apply
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
FEV1
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: REGN13335
Drug: REGN13335
Drug: Placebo
Drug: REGN13335
Drug: REGN13335
Administered per the protocol
Administered per the protocol
Change from baseline in Pulmonary Vascular Resistance (PVR)
Time frame: At week 24
Occurrence of Treatment-Emergent Adverse Events (TEAEs)
Time frame: Through end of study, up to approximately 2.5 years
Severity of TEAEs
Time frame: Through end of study, up to approximately 2.5 years
Change from baseline in circulating N-Terminal pro-B-type Natriuretic Peptide (NT-proBNP) concentrations
Time frame: At week 24
Change from baseline in mean pulmonary artery pressure
Time frame: At week 24
Change from baseline in cardiac output
Time frame: At week 24
Change from baseline in cardiac index
Time frame: At week 24
Change from baseline in right atrial pressure
Time frame: At week 24
Change from baseline in 6-Minute Walk Distance (6MWD)
Time frame: At week 24
Concentrations of functional REGN13335 in plasma
Time frame: Through end of study, up to approximately 2.5 years
Concentrations of total soluble Platelet-Derived Growth Factor-B (PDGF-B) ligands in plasma
Time frame: Through end of study, up to approximately 2.5 years
Plan to share: Yes — All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: When Regeneron has: received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry) the legal authority to share the data, and ensured the ability to protect participant privacy
Access criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
Data sharing details ↗ · vivli.org
Started May 2026 (actual). Primary completion is estimated for Feb 2028, 21 months after the start.
Of 28 industry-sponsored phase 2 interventional studies under Pulmonary Arterial Hypertension, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 19 and three quarters within 48. This study's planned 21 months is below that.
Counting every sponsor, half of 51 studies reached it within 44 months; a quarter within 26 and three quarters within 65.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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Pulmonary Arterial Hypertension →