REGN13335 for adults with pulmonary arterial hypertension (PAH)

A Phase 2, Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy, Safety, Pharmacokinetics, and Pharmacodynamic Effects of REGN13335, an Anti-PDGF-B Monoclonal Antibody, in Adults With Pulmonary Arterial Hypertension

Researchers will test whether the experimental antibody REGN13335 is safe and helps adults with pulmonary arterial hypertension who are already taking other PAH medicines.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 99 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Regeneron Pharmaceuticals (Industry-sponsored)
• Locations: 3 sites (Aurora, Colorado and 2 other locations)
• Trial ID: NCT07318597 on ClinicalTrials.gov

What this trial studies

This Phase 2 interventional trial gives adults with WHO functional class II–III PAH either REGN13335 or placebo in addition to their stable background PAH therapy to test safety and potential benefit. The study tracks side effects, measures drug levels in blood over time, and looks for anti-drug antibodies that could affect effectiveness or cause reactions. Key eligibility includes confirmed Group 1 PAH with PVR ≥400 dynes·sec/cm5 by right heart catheterization and a 6-minute walk distance between 150 and 550 meters. The trial is sponsored by Regeneron and is conducted at academic centers in the United States, United Kingdom, and South Korea.

Who should consider this trial

Good fit: Adults with confirmed Group 1 PAH who are WHO functional class II or III, have PVR ≥400 dynes·sec/cm5, a 6-minute walk distance of 150–550 meters, and are on a stable PAH treatment regimen are ideal candidates.

Not a fit: People with other forms of pulmonary hypertension (Groups 2–5), left-heart disease with PAWP >15 mm Hg, or who do not meet the PVR or 6MWD criteria are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, REGN13335 could improve symptoms or slow disease progression for people with PAH who remain symptomatic despite standard therapies.

How similar studies have performed: Previous attempts to target PDGF signaling in PAH (for example with imatinib) showed some hemodynamic benefit but were limited by safety concerns, so this approach has some precedent but remains experimental.

Eligibility criteria

Key Inclusion Criteria:

1. Documented clinical diagnosis of PAH (Group 1 PH according to the 7th World Symposium on Pulmonary Hypertension (WSPH))
2. WHO functional class II or III (slight to marked limitation of functional status due to PAH)
3. Receiving background Standard Of Care (SOC) therapy for PAH on a stable dose and regimen, as determined by the investigator, as described in the protocol
4. PVR ≥400 dynes∙sec/cm\^5 (5 Wood units) based on Right Heart Catheterization (RHC) during the screening period
5. Has 6MWD ≥150 and ≤550 meters repeated twice during screening as described in the protocol

Key Exclusion Criteria:

1. Has Group 2 (PH associated with left heart disease), Group 3 (PH associated with lung diseases and/or hypoxia), Group 4 (PH associated with pulmonary artery obstructions), or Group 5 (PH with unclear and/or multifactorial mechanisms) PH according to the 7th WSPH
2. Pulmonary Arterial Wedge Pressure (PAWP) \>15 mm Hg by RHC during the screening period
3. History of left-sided heart disease and/or clinically significant cardiac disease, as described in the protocol
4. Obstructive lung disease defined as Forced Expiratory Volume in 1 second (FEV1)/Forced Vital Capacity \<0.7 and FEV1 \<70% of the predicted value as described in the protocol
5. Evidence of interstitial lung disease as defined in the protocol
6. Evidence of chronic thromboembolic pulmonary disease or acute pulmonary embolism as described in the protocol
7. Participants requiring anticoagulation and/or antiplatelet therapy for an underlying medical condition as described in the protocol
8. Has any history of intracranial bleeding or any history of elevated intracranial pressure
9. Has any history of bleeding meeting criteria as described in the protocol

Note: Other protocol-defined Inclusion/ Exclusion criteria apply

Where this trial is running

Aurora, Colorado and 2 other locations

• University of Colorado Denver — Aurora, Colorado, United States (Recruiting)
• Seoul National University Hospital — Seoul, South Korea (Recruiting)
• Imperial College Healthcare NHS Trust, Hammersmith Hospital — London, United Kingdom (Recruiting)

Study contacts

• Study coordinator: Clinical Trials Administrator

Conditions Pulmonary Arterial Hypertension; Pulmonary Hypertension; Elevated Pulmonary Vascular Resistance; World Health Organization functional class II or III; Platelet-Derived Growth Factor-B; REGN13335