A Study of Sotatercept (MK-7962) in Japanese Children With Pulmonary Arterial Hypertension (PAH) (MK-7962-032)

A Phase 2 Open-label Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Efficacy of Sotatercept (MK-7962) in Japanese Children From 1 to Less Than 18 Years of Age With PAH on Standard of Care.

The goal of this study is to learn about the safety of sotatercept and how well Japanese children tolerate it, when taken along with standard (usual) pulmonary arterial hypertension (PAH) treatment. Researchers also want to learn what happens to it in a person's body over time and whether it lowers resistance in blood vessels in the lungs.

Study Overview

• Status: Not yet recruiting
• Conditions: Pulmonary Arterial Hypertension
• Intervention / Treatment: Biological: Sotatercept

• Study Type: Interventional
• Enrollment (Estimated): 6
• Phase: Phase 2

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

• Has pulmonary arterial hypertension (PAH, World Health Organization Group 1) confirmed by a prior right heart catheterization
• Has idiopathic, heritable, drug- or toxin-induced PAH, connective tissue disease-associated PAH, repaired congenital heart disease-associated PAH, or PAH with coincidental shunt
• Has PAH classified as World Health Organization Functional Class I, or symptomatic World Health Organization Functional Class II to IV
• Has been receiving stable standard-of-care background therapy for PAH for at least 90 days
• Is Japanese

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

• History of left-sided heart disease
• Has severe congenital or developmental abnormalities of the lung, thorax, and/or diaphragm
• History of Eisenmenger syndrome, Potts shunt, or recent atrial septostomy within 180 days
• Has unrepaired or residual cardiac shunt with Qp/Qs >1.5
• Has pulmonary veno-occlusive disease, pulmonary capillary hemangiomatosis, or overt signs of pulmonary capillary and/or venous involvement
• PAH associated with portal hypertension
• Known visceral arteriovenous malformations
• History of full or partial pneumonectomy
• Untreated more than mild obstructive sleep apnea
• History of known pericardial constriction
• Family history of sudden cardiac death or long QT syndrome
• History of symptomatic coronary disease within 6 months or cerebrovascular accident within 3 months
• Prior treatment with sotatercept or luspatercept

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Sotatercept; Participants receive sotatercept by subcutaneous injection every 3 weeks (Q3W) for up to approximately 24 weeks while continuing standard-of-care background therapy for PAH. Participants start at a dose of 0.3 mg/kg Q3W, and may titrate up to the target dose of 0.7 mg/kg SC injection Q3W starting at Week 6 based on protocol-defined dose-escalation guidance. After Week 24, participants who meet certain requirements may choose to continue receiving sotatercept for up to 58 months.

Biological: Sotatercept; Sotatercept subcutaneous injection every 3 weeks; Other Names: ACE-011; MK-7962; ActRIIA-IgG1Fc; WINREVAIR®

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With One or More Adverse Events	An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.	Up to approximately 24 weeks
Number of Participants Who Discontinue Study Intervention Due to an Adverse Event	An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.	Up to approximately 24 weeks
Laboratory Parameter (Hematology): Concentration of Hemoglobin	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The concentration of hemoglobin will be presented.	Up to approximately 24 weeks
Laboratory Parameter (Hematology): Hematocrit	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The hematocrit will be presented.	Up to approximately 24 weeks
Laboratory Parameter (Hematology): Red Blood Cell (RBC) Count	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The RBC count will be presented.	Up to approximately 24 weeks
Laboratory Parameter (Hematology): Reticulocyte Count	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The reticulocyte count will be presented.	Up to approximately 24 weeks
Laboratory Parameter (Hematology): Platelet Count	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The platelet count will be presented.	Up to approximately 24 weeks
Blood Pressure (BP)	BP will be assessed while the participant was seated after a period of rest in a quiet setting with no distractions (eg, television and cell phones).	Up to approximately 24 weeks
Number of Participants with Detectable Anti-Drug Antibodies (ADAs)	Blood samples will be collected to assess antidrug antibodies to sotatercept. The number of participants with detectable ADAs at any time during the study will be presented.	Up to approximately 24 weeks
Number of Participants with Detectable Neutralizing Antibodies to Sotatercept	Neutralizing antibody analysis will be performed on blood samples for participants who are confirmed as antidrug antibody-positive. The number of participants with detectable neutralizing antibodies at any time during the study will be presented.	Up to approximately 24 weeks
Serum Trough Concentration (Ctrough) of Sotatercept	Serum samples collected predose will be used to determine serum trough concentration (Ctrough) of sotatercept.	At designated time points and up to approximately 24 weeks
Change From Baseline in Pulmonary Vascular Resistance Index (PVRI)	The change from baseline in PVRI will be presented.	Baseline and Week 24

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Change from Baseline in N-terminal Prohormone B-type Natriuretic Peptide (NT-proBNP)	The change from baseline in plasma NT-proBNP levels will be reported.	Baseline and Week 24
Percentage of Participants Who Either Improved or Maintained Their World Health Organization Functional Class (WHO FC)	The severity of an individual's PAH symptoms will be graded using the WHO FC system. WHO functional classification for PAH range from Class I (no limitation in physical activity, no dyspnea with normal activity), Class II (slight limitation of physical activity), Class III (marked limitation of physical activity) and Class IV (cannot perform a physical activity without any symptoms, dyspnea at rest). The change from baseline in WHO FC will be classified into "Improved", "No change" and "Worsened". Improvement = reduction in FC, worsened = increase in FC and no change = no change in FC.	Baseline and Week 24
Mean Change from Baseline in 6-Minute Walk Distance (6MWD)	6MWD will be assessed using the 6-minute walk test (6MWT).	Baseline and Week 24
Number of Participants With One or More Adverse Events	An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.	From Week 24 up to approximately 58 months
Number of Participants Who Discontinue Study Intervention Due to an Adverse Event	An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.	From Week 24 up to approximately 58 months
Laboratory Parameter (Hematology): Concentration of Hemoglobin	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The concentration of hemoglobin will be presented.	From Week 24 up to approximately 58 months
Laboratory Parameter (Hematology): Hematocrit	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The hematocrit will be presented.	From Week 24 up to approximately 58 months
Laboratory Parameter (Hematology): Red Blood Cell (RBC) Count	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The RBC count will be presented.	From Week 24 up to approximately 58 months
Laboratory Parameter (Hematology): Reticulocyte Count	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The reticulocyte count will be presented.	From Week 24 up to approximately 58 months
Laboratory Parameter (Hematology): Platelet Count	Hematological parameters will be investigated in blood samples from participants by means of clinical laboratory assays and evaluated by the investigator. The platelet count will be presented.	From Week 24 up to approximately 58 months
Blood Pressure (BP)	BP will be assessed while the participant was seated after a period of rest in a quiet setting with no distractions (eg, television and cell phones).	From Week 24 up to approximately 58 months
Number of Participants with Detectable ADAs	Blood samples will be collected to assess antidrug antibodies to sotatercept. The number of participants with detectable ADAs at any time during the study will be presented.	From Week 24 up to approximately 58 months
Number of Participants with Detectable Neutralizing Antibodies to Sotatercept	Neutralizing antibody analysis will be performed on blood samples for participants who are confirmed as ADA-positive. The number of participants with detectable neutralizing antibodies at any time during the study will be presented.	From Week 24 up to approximately 58 months

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information

Study record dates

Study Major Dates

• Study Start (Estimated): August 31, 2026
• Primary Completion (Estimated): May 24, 2029
• Study Completion (Estimated): May 16, 2031

Study Registration Dates

• First Submitted: June 9, 2026
• First Submitted That Met QC Criteria: June 9, 2026
• First Posted (Actual): June 15, 2026

Study Record Updates

• Last Update Posted (Actual): June 15, 2026
• Last Update Submitted That Met QC Criteria: June 9, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Hypertension, Pulmonary; Pulmonary Arterial Hypertension; ACE-011
• Other Study ID Numbers: 7962-032; MK-7962-032 (Other Identifier: MSD)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No