A Phase 4 interventional study of Sotatercept and vasodilator-based PAH therapy in Eisenmenger Syndrome and Pulmonary Arterial Hypertension of Congenital Heart Disease, sponsored by Kazuya Hosokawa. Recruiting at 10 sites in Japan. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-01-21.
Sponsored by Kazuya Hosokawa · Phase 4, Interventional, and Treatment
What is this study about? This study will test whether adding sotatercept to usual medicines for pulmonary arterial hypertension (PAH) can help adults who have PAH due to unrepaired congenital heart defects (atrial or ventricular septal defect, or patent ductus arteriosus), including Eisenmenger syndrome. These conditions often cause long-standing changes in the lung blood vessels and low oxygen levels.
Who can join? About 36 adults (age ≥18 years) in Japan whose PAH has not improved enough with pulmonary vasodilators may join. People with very severe symptoms (WHO class IV) or other serious illnesses will not be enrolled.
What will happen if I join?
Participants will be randomly assigned (like a coin flip, in a 2:1 ratio) to:
Sotatercept + vasodilator-based PAH care, or
vasodilator-based PAH care alone. The study lasts 24 weeks. Those who receive sotatercept will have injections every 3 weeks. All participants will have clinic visits and tests at the start, week 12, and week 24, including a 6-minute walk test (how far you can walk in 6 minutes), blood tests, questionnaires, and other heart-lung assessments used in routine PAH care.
What are the possible benefits? Sotatercept improved exercise capacity and heart-lung measures in other PAH studies, but people with unrepaired heart defects were not included. This study may or may not help you directly, but it may help doctors learn how to use sotatercept safely in this group.
What are the possible risks? Side effects seen with sotatercept include increase in haemoglobin, low platelets, nosebleeds, telangiectasia (small dilated blood vessels), bleeding, and blood clots. People with Eisenmenger syndrome can have both bleeding (for example, haemoptysis) and clotting risks. The study will check complete blood counts (CBC) regularly and adjust or pause dosing using label-based rules. Other risks are those of standard PAH care and blood tests.
Time and location The study is conducted at multiple hospitals in Japan. Study participation lasts about 6 months.
Costs and payments The study drug and study-specific tests will be provided at no cost. Usual medical care not required by the study will follow each hospital's standard billing. There is no required payment to join. Any travel reimbursement or stipends will follow site policy.
Privacy Your information will be kept confidential. Results will be shared in journals and at meetings without using your name.
Who to contact If you are interested or have questions, please contact the study team at the participating hospital.
23 studies on the registry are indexed under Eisenmenger Complex; 5 are open to participants now.
This study's planned enrollment of 36 is close to the median of 40 across 15 interventional studies indexed under Eisenmenger Complex.
Browse Eisenmenger Complex studies →This is the only study on the registry with Kazuya Hosokawa as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
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.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Sotatercept · Drug: vasodilator-based PAH therapy
Drug: vasodilator-based PAH therapy
Sotatercept will be administered subcutaneously every 3 weeks for 24 weeks (total 8 injections): 0.3 mg/kg lead-in at Visit 1, then 0.7 mg/kg from Visit 2 if safety criteria are met. Dose holds/reductions follow label-concordant rules based on complete blood count (CBC) prior to each dose (e.g., hemoglobin rise \>4.0 g/dL from baseline; or \>2.0 g/dL from the previous dose and above ULN; or \>2.0 g/dL above ULN; and platelet count \<50,000/µL). Participants continue stable background PAH therapy (endothelin, nitric-oxide, prostacyclin pathways) per protocol; initiation or up-titration of PAH drugs during the 24-week treatment period is generally not permitted unless clinically mandated for safety and recorded as a protocol deviation.
Participants receive no sotatercept. They continue site-standard, stable PAH therapy for 24 weeks (endothelin receptor antagonist, PDE5 inhibitor/riociguat, and/or prostacyclin class as clinically indicated). Changes to background therapy are discouraged during the 24-week period unless required for safety; any changes are captured for analysis. The same visit schedule and assessments (e.g., 6-minute walk test, biomarkers, clinical events) apply as in the sotatercept arm.
Change in 6-minute walk distance at 24 weeks from baseline
Time frame: 24 weeks
Mortality or lung transplantation
Time frame: 24 weeks
PH-related hospitalisation or initiation of parenteral prostacyclin
Time frame: 24 weeks
Change in WHO functional class at 24-week from baseline
A higher score indicates more severe symptom
Time frame: 24 weeks
Change in NT-pro BNP at 24-week from baseline
Time frame: 24 weeks
Change in emPHasis-10 at 24-week from baseline
A higher score indicates more severe symptom
Time frame: 24 weeks
PAH specific genetic test
Time frame: 0 week
Changes in blood pressure (systolic and diastolic)
Office resting BP
Time frame: 0, 12, 24 weeks
Changes in pulse rate
bpm
Time frame: 0, 12, 24 weeks
Changes in oxygen saturation
Pulse Oxygen Saturation (Office, Resting)
Time frame: 0, 12, 24 weeks
Changes in hemoglobin
g per dL
Time frame: 0, 12, 24 weeks
Changes in platlet counts
Time frame: 0, 12, 24 weeks
Changes in catheter-based mPAP
mm Hg
Time frame: 0, 24 weeks
Changes in catheter-based PVR
Wood units
Time frame: 0, 24 weeks
Changes in catheter-based Qp/Qs
Time frame: 0, 24 weeks
Plan to share: No
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Studies of the drug tested here: Sotatercept