Intervention: Macitentan
Trial phase: Phase 3
ATC code: C02KX04 | C02KX54
SMILES: CCCNS(=O)(=O)Nc1ncnc(OCCOc2ncc(Br)cn2)c1-c1ccc(Br)cc1
Sex: All
Age groups: Child | Adult | Older Adult
Healthy volunteers: No
Participants at risk: 114
Group description: Subjects receive macitentan 10 mg orally to be taken once daily. 114 subjects were exposed to Macitentan 10 mg for 15.93 weeks on average.
Eligibility criteria:
Inclusion Criteria:

Subjects:

not participating in the hemodynamic sub-study: males or females ≥ 12 years of age.
participating in the hemodynamic sub-study: males or females ≥ 18 years of age.

Subjects (including those with Down Syndrome [DS]) with confirmed Eisenmenger Syndrome [ES] (European Society of Cardiology [ESC] and the European Respiratory Society [ERS] guidelines):

Established by echocardiography as:

Large congenital shunting defect at atrial, ventricular or arterial level*
and right to left shunt or bi-directional shunt with prevalent right to left direction.
Resting peripheral oxygen saturation (SpO2) ≤ 90% and > 70% (pulse oximetry, room air).

The lower limit is 65% if a subject is living at an altitude greater than 2500 m above sea level.

*Subjects with any of the following open defects are eligible for the study either as an isolated defect or in combination:

atrial septal defect (ASD)
ventricular septal defect (VSD)
partial or complete atrioventricular septal defect (AVSD)
patent ductus arteriosus (PDA)
aortopulmonary window (AP window)
total or partial anomalous pulmonary venous return (TAPVR, PAPVR) The defects may be either unoperated or previously palliated surgically (provided significant residual defect remains).

The Steering Committee will review the echocardiography data of all subjects (main study and sub study) to confirm eligibility prior to Randomization.

Subjects with the following findings at cardiac catheterization:

Mean resting pulmonary arterial pressure (mPAP) > 25 mmHg
Pulmonary capillary wedge pressure (PCWP) or mean left atrial pressure (LAP) or left ventricular end diastolic pressure (LVED) ≤ 15 mmHg
Pulmonary vascular resistance (PVR) ≥ 800 dyn∙s/cm5 or ≥ 10 Wood units
Subjects with WHO functional class ≥ II.
Subjects able to reliably perform the the 6-minute walk test (6MWT) with a minimum distance of 50 m and a maximum distance of 450 m.

Exclusion Criteria:

- Main study and hemodynamic sub-study: Any of the following conditions previously known or identified via cardiac catheterization or echocardiography:

Pulmonary arterial or venous stenosis > 25% size of native pulmonary artery (PA) or pulmonary vein
Severe tricuspid regurgitation in the setting of left to right shunt at the ventricular or atrial level
Greater than mild tricuspid stenosis
Intracavitary RV outflow obstruction
Greater than mild mitral stenosis
Intracavitary LV outflow obstruction
Subvalvular or supravalvular aortic stenosis
Aortic coarctation
Greater than moderate mitral regurgitation
Recognized extracardiac systemic venous collaterals to the pulmonary venous circulation
Recognized hepatic wedge pressure-inferior vena cava pressure gradient >12 mm Hg
PCWP "v" waves >20 mmHg
Tetralogy of Fallot
Truncus arteriosus
Interrupted aortic arch
Transposition of great arteries
Single ventricle defects: absent AV connection (mitral or tricuspid atresia), double inlet AV connections left or right ventricle, functional univentricular heart (unbalanced AVSD, hypoplastic RV, double outlet RV), hypoplastic left heart syndrome
Ebstein's anomaly
Severe aortic regurgitation
Pulmonary atresia
PAPVR or TAPVR, ONLY if there is lung hypoplasia or if documentation confirming the absence of lung hypoplasia does not exist.

For subjects participating in the hemodynamic sub-study the following will also be considered exclusion criteria:

SVC stenosis >25% size of native vessel
PDA, AP window, TAPVR, PAPVR, or ASD sinus venosus with anomalous pulmonary veins

Down Syndrome

Subjects with deterioration of their clinical status within 3 months prior to Screening or during the Screening period.
Known moderate-to-severe restrictive (i.e., total lung capacity [TLC] < 60% of predicted value) or obstructive lung disease (i.e., forced expiratory volume in one second [FEV1] < 80 % of predicted value, and with FEV1 / forced vital capacity [FVC] < 70%)
Treatment with prostanoids within 1 month prior to Randomization
Subjects who initiated a PDE-5 inhibitor within 1 month prior to Randomization or those on a PDE-5 inhibitor for whom the dose has not been stable within 1 month prior to Randomization
Treatment with endothelin receptor antagonists (ERAs) within 1 month prior to Randomization
Subjects who initiated diuretics within 1 week prior to Randomization or subjects whose diuretic treatment has not been stable for at least 1 week prior to Randomization
Subjects being considered for an organ transplant