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A Study of Sotatercept for Patients With Eisenmenger Syndrome or Unrepaired Shunt-Associated Pulmonary Arterial Hypertension Resistant to Vasodilator Therapy

An Open-label, Randomized, Controlled Trial to Evaluate the Efficacy of Sotatercept Add-on Therapy Compared to Standard PAH Therapy With Pulmonary Vasodilators for Pulmonary Arterial Hypertension Associated With Pulmonary Vasodilator-resistant, Unrepaired Congenital Shunts (ASD, VSD, PDA) Including Eisenmenger Syndrome:SuMILE Trial

Status
Recruiting
Phases
Phase 4
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07356778
Acronym
SuMILE
Enrollment
36
Registered
2026-01-21
Start date
2025-10-07
Completion date
2028-04-30
Last updated
2026-01-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Eisenmenger Syndrome, Pulmonary Arterial Hypertension of Congenital Heart Disease

Keywords

Eisenmenger syndrome, pulmonary arterial hypertension, Congential heart disease, sotatercept

Brief summary

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.

Interventions

DRUGSotatercept

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.

DRUGvasodilator-based PAH therapy

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.

Sponsors

Kazuya Hosokawa
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* adults (≥18 years) * unrepaired ASD, VSD or PDA * ≥90 days of pulmonary vasodilator therapy; and either (i) pulmonary vascular resistance (PVR) ≥5 Wood units and mean pulmonary arterial pressure (mPAP) \> 20 mm Hg on right heart catheterization within 180 days, or (ii) echocardiographic tricuspid regurgitation velocity \>3.4 m/s with right-to-left/bidirectional shunt plus resting SpO₂ ≤92% consistent with cyanosis * baseline 6MWD ≥100 m * ability to complete questionnaires

Exclusion criteria

* WHO functional class IV; other unrepaired intracardiac shunts * severe renal/hepatic/parenchymal lung disease or LVEF \<40% * prior sotatercept use * contraindication to sotatercept per label * investigator-judged unsuitability

Design outcomes

Primary

MeasureTime frame
Change in 6-minute walk distance at 24 weeks from baseline24 weeks

Secondary

MeasureTime frameDescription
Change in NT-pro BNP at 24-week from baseline24 weeks
Change in emPHasis-10 at 24-week from baseline24 weeksA higher score indicates more severe symptom
Mortality or lung transplantation24 weeks
PH-related hospitalisation or initiation of parenteral prostacyclin24 weeks
Change in WHO functional class at 24-week from baseline24 weeksA higher score indicates more severe symptom

Countries

Japan

Contacts

CONTACTKazuya Hosokawa, MD, PhD
hosokawa.kazuya.712@m.kyushu-u.ac.jp+81-92-642-5360
CONTACTKeimei Yoshida, MD, PhD
yoshida.keimei.713@m.kyushu-u.ac.jp

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 14, 2026