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A Study of Sotatercept for the Treatment of Pulmonary Arterial Hypertension (MK-7962-003/A011-11)(STELLAR)

A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Compare the Efficacy and Safety of Sotatercept Versus Placebo When Added to Background Pulmonary Arterial Hypertension (PAH) Therapy for the Treatment of PAH

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04576988
Enrollment
324
Registered
2020-10-06
Start date
2021-01-25
Completion date
2022-12-06
Last updated
2024-09-19

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

Conditions

Pulmonary Arterial Hypertension

Keywords

Pulmonary Hypertension

Brief summary

The objectives of this study are to evaluate the efficacy and safety of sotatercept (MK-7962) treatment (plus background pulmonary arterial hypertension (PAH) therapy) versus placebo (plus background PAH therapy) at 24 weeks in adults with PAH. The primary hypothesis of the study is that the participants receiving sotatercept will have improved 6-minute walk distance (6MWD) at 24 weeks compared to participants receiving placebo.

Detailed description

This is a Phase 3, randomized, double-blind, placebo-controlled, multicenter, parallel-group study in subjects with symptomatic PAH who present with idiopathic or heritable PAH, PAH associated with connective tissue diseases (CTD), drug or toxin induced, post shunt correction PAH, or PAH presenting at least 1 year following the correction of congenital heart defects (CHDs), and currently on background PAH therapy. The primary efficacy endpoint of the study is exercise capacity, as measured by the 6-minute walk distance (6MWD) measured at 24 week following initiation of treatment. Study duration will be approximately 2 years. A stratified Wilcoxon test will be used for analysis of the primary endpoint, with appropriate imputation for missing data, as detailed in the Statistical Analysis Plan. An unblinded, external, independent Data Monitoring Committee (DMC) will monitor participant safety throughout the course of the study. Participants completing this study will be eligible to receive sotatercept in a separate, open-label extension study.

Interventions

BIOLOGICALSotatercept

Sotatercept at a starting dose of 0.3 mg/kg with a target dose of 0.7 mg/kg administered subcutaneously (SC) every 21 days plus background PAH therapy.

DRUGPlacebo

Placebo administered subcutaneously (SC) every 21 days plus background PAH therapy.

Background PAH therapy may consist of the following drug classes: an endothelin-receptor antagonist (ERA), a phosphodiesterase 5 (PDE5) inhibitor, a soluble guanylate cyclase stimulator, and/or a prostacyclin analogue or receptor agonist.

Sponsors

Acceleron Pharma, Inc., a wholly-owned subsidiary of Merck & Co., Inc., Rahway, NJ USA
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

Study participants, care providers. Investigators and outcomes assessor will be masked to the study intervention until the final participant completes the 24-week efficacy assessment.

Intervention model description

Participants will be randomized to one of two treatment arms to receive either sotatercept (0.7 mg/kg) by subcutaneous administration once every 3 weeks, or placebo. All participants will be on concurrent, stable background PAH therapy. Randomization will be stratified by baseline WHO Functional Class (Class II or III) and by background PAH therapy (mono/double or triple therapy)

Eligibility

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

Inclusion criteria

Key Inclusion Criteria: * Age ≥ 18 years * Documented diagnostic right heart catheterization (RHC) at any time prior to screening confirming the diagnosis of World Health Organization (WHO) pulmonary arterial hypertension (PAH) Group 1 in any of the following subtypes: * Idiopathic PAH * Heritable PAH * Drug/toxin-induced PAH * PAH associated with connective tissue disease * PAH associated with simple, congenital systemic to pulmonary shunts at least 1 year following repair * Symptomatic PAH classified as WHO Functional Class (FC) II or III * Baseline RHC performed during the Screening Period documenting a minimum pulmonary vascular resistance (PVR) of ≥ 5 Wood units (WU) and a pulmonary capillary wedge pressure (PCWP) or left ventricular end-diastolic pressure of ≤ 15 mmHg. * On stable doses of background PAH therapy and diuretics (i.e., patient-specific dose goal for each therapy already achieved) for at least 90 days prior to screening; for infusion prostacyclins, dose adjustment within 10% of optimal dose is allowed per medical practice * Background PAH therapy refers to approved PAH-specific medications and may consist of monotherapy or combination therapy with ERA, PDE5 inhibitors, soluble guanylate cyclase stimulators, and/or prostacyclin analogues or receptor agonists. Background PAH therapy should be stable at least 90 days prior to screening and remain stable throughout the study * Stable diuretic therapy is defined as no addition of a new diuretic and no switching of a pre-existent oral diuretic to parenteral administration; however, dose adjustments (up or down) in pre-existent oral diuretics are acceptable * 6-Minute Walk Distance (6MWD) ≥ 150 and ≤ 500 m repeated twice at screening (measured at least 4 hours apart, but no longer than 1 week), and both values are within 15% of each other (calculated from the highest value) * Females of childbearing potential must: * Have 2 negative urine or serum pregnancy tests as verified by the investigator prior to starting study therapy; she must agree to ongoing urine or serum pregnancy testing during the study and until 8 weeks after the last dose of the study drug * If sexually active, have used, and agree to use, highly effective contraception without interruption, for at least 28 days prior to starting the investigational product, during the study (including dose interruptions), and for 16 weeks (112 days) after discontinuation of study treatment * Refrain from breastfeeding a child or donating blood, eggs, or ovum for the duration of the study and for at least 16 weeks (112 days) after the last dose of study treatment * Male participants must: * Agree to use a condom, defined as a male latex condom or nonlatex condom NOT made out of natural (animal) membrane (e.g., polyurethane), during sexual contact with a pregnant female or a female of childbearing potential while participating in the study, during dose interruptions and for at least 16 weeks (112 days) following investigational product discontinuation, even if he has undergone a successful vasectomy * Refrain from donating blood or sperm for the duration of the study and for 16 weeks (112 days) after the last dose of study treatment * Ability to adhere to study visit schedule and understand and comply with all protocol requirements * Ability to understand and provide written informed consent Key

Exclusion criteria

* Diagnosis of pulmonary hypertension WHO Groups 2, 3, 4, or 5 * Diagnosis of the following PAH Group 1 subtypes: human immunodeficiency virus (HIV)-associated PAH and PAH associated with portal hypertension. Exclusions in PAH Group I should also include schistosomiasis associate PAH and pulmonary veno occlusive disease * Hemoglobin (Hgb) at screening above gender-specific upper limit of normal (ULN), per local laboratory test * Baseline platelet count \< 50,000/mm\^3 (\< 50.0 x 109/L) at screening * Uncontrolled systemic hypertension as evidenced by sitting systolic blood pressure \> 160 mmHg or sitting diastolic blood pressure \> 100 mmHg during screening visit after a period of rest * Baseline systolic blood pressure \< 90 mmHg at screening * Pregnant or breastfeeding women * Any of the following clinical laboratory values at the screening visit: * Estimated glomerular filtration rate (eGFR) \< 30 mL/min/m2 (as defined by the Modification of Diet in Renal Disease \[MDRD\] equation) * Serum alanine aminotransferase, aspartate aminotransferase, or total bilirubin levels \> 3 × ULN (bilirubin criterion waived if there is a documented history of Gilbert's syndrome) * Currently enrolled in or have completed any other investigational product study within 30 days for small molecule drugs or within 5 half-lives for biologics prior to the date of signed informed consent * Prior exposure to sotatercept (ACE-011) or luspatercept (ACE 536) and/or excipients or known allergic reaction to either one * History of full pneumonectomy * Pulmonary function test (PFT) values of forced vital capacity (FVC) \< 60% predicted at the screening visit or within 6 months prior to the screening visit. If PFT is not available, a chest CT scan showing more than mild interstitial lung disease (ILD) at the screening visit or 1 year prior to it * Initiation of an exercise program for cardiopulmonary rehabilitation within 90 days prior to the screening visit or planned initiation during the study (participants who are stable in the maintenance phase of a program and who will continue for the duration of the study are eligible) * History of more than mild obstructive sleep apnea that is untreated * Known history of portal hypertension or chronic liver disease, including hepatitis B and/or hepatitis C (with evidence of recent infection and/or active virus replication), defined as mild to severe hepatic impairment (Child-Pugh Class A-C) * History of restrictive, constrictive or congestive cardiomyopathy * History of atrial septostomy within 180 days prior to the screening visit * Electrocardiogram (ECG) with Fridericia's corrected QT interval (QTcF) \> 500 ms during the screening period * Personal or family history of long QT syndrome (LQTS) or sudden cardiac death * Left ventricular ejection fraction \< 45% on historical echocardiogram within 6 months prior to the screening visit * Any symptomatic coronary disease events (prior myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft surgery, or cardiac anginal chest pain) within 6 months prior to the screening visit. Note: Anginal pain can be ignored as an exclusion criterion if coronary angiography shows no obstructions * Cerebrovascular accident within 3 months prior to the screening visit * Acutely decompensated heart failure within 30 days prior to the screening visit, as per investigator assessment * Significant (≥ 2+ regurgitation) mitral regurgitation or aortic regurgitation valvular disease * Received intravenous inotropes (e.g., dobutamine, dopamine, norepinephrine, vasopressin) within 30 days prior to the screening visit

Design outcomes

Primary

MeasureTime frameDescription
Change From Baseline in 6-Minute Walk Distance (6MWD) at Week 24Baseline and Week 24The 6MWD was the distance walked in 6 minutes as a measure of functional capacity. This was assessed using the 6-minute walk test (6MWT). Per protocol, change from baseline in 6MWD at Week 24 was reported for DBPC period.
Number of Participants Who Experienced an Adverse Event (AE)Up to approximately 24 weeksAn AE was any untoward medical occurrence in a study participant administered a study drug, which did not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study drug whether or not it was considered related to the study drug. Per protocol, the number of participants who reported an AE were reported for DBPC period.
Number of Participants Who Discontinued Study Treatment Due to an AEUp to approximately 24 weeksAn AE was any untoward medical occurrence in a study participant administered a study drug, which did not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study drug whether or not it was considered related to the study drug. Per protocol, the number of participants who discontinued study treatment due to an AE were reported for DBPC period.

Secondary

MeasureTime frameDescription
Change From Baseline in the Percentage of Participants Who Improve in WHO FC at Week 24Baseline and Week 24The severity of participant's pulmonary arterial hypertension (PAH) symptoms will be graded using the WHO FC system. WHO functional classification for PAH ranges 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). Participants who improve in WHO FC were classified into Improved, No change and Worsened. Improvement = reduction in FC, worsened = increase in FC and no change = no change in FC. Per protocol, change from baseline in the percentage of participants who improve in WHO FC at Week 24 were reported for DBPC period.
Time to Death or the First Occurrence of Clinical Worsening EventUp to approximately 18 monthsClinical Worsening events are defined as any of the following: worsening-related listing for lung and/or heart transplant; need to initiate rescue therapy with an approved background PAH therapy or the need to increase the dose of infusion prostacyclin by 10% or more; need for atrial septostomy; hospitalization for worsening of PAH (≥ 24 hours); or deterioration of PAH defined by both of the following events occurring at any time: worsened WHO FC and decrease in 6MWD by ≥15% confirmed by 2 tests at least 4 hours apart, but no more than 1 week. Per protocol, time to death or the first occurrence of clinical worsening event was reported.
Change From Baseline in Percentage of Participants Who Maintain or Achieve a Low Risk Score Using the Simplified French Risk Score Calculator at Week 24Baseline and Week 24The simplified French risk scoring system was based on the 2015 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines for the diagnosis and treatment of pulmonary hypertension (PH). In this study, the noninvasive parameters were used to determine the score. 'Low risk' was defined as attaining or maintaining all 3 low-risk criteria: WHO FC I or II, 6MWD \> 440 m, and NT-proBNP \<300 ng/L. Per protocol, change from baseline in percentage of participants who maintained or achieved a low risk score using the simplified French risk score calculator at Week 24 was reported for DBPC period.
Change From Baseline in the Percentage of Participants Achieving Multicomponent Improvement at Week 24Baseline and Week 24Multicomponent Improvement was defined as consisting of all of the following: (a) Improvement in 6MWD (increase ≥30 meters) (b) Improvement in N-terminal pro b-type natriuretic peptide (NT-proBNP; decrease in NT-proBNP ≥30%) or maintenance/achievement of NT-proBNP level \<300 ng/L (c) Improvement in World Health Organization (WHO) Functional Class (FC) or maintenance of WHO FC II. Per protocol, change from baseline in the percentage of participants achieving multicomponent improvement at Week 24 was reported for DBPC period.
Change From Baseline in the Cardiopulmonary Symptoms Domain Score of PAH-SYMPACT® at Week 24Baseline and Week 24The PAH SYMPACT is a 23-item questionnaire to measure PAH-related symptoms and impact of PAH on daily life. The cardiopulmonary symptoms consist of shortness of breath, fatigue, lack of energy, swelling in the ankles or legs, swelling in the stomach area, and cough. Participants were asked to recall and report on each item experienced in past 7 days. Score for each item ranges from 0 (no symptom at all) to 4 (very severe symptoms). The mean individual symptom item score was determined for each of the 6 items and a domain score was calculated by summing the mean individual symptom item scores and dividing by the number of items (range: 0=no cardiopulmonary symptoms to 4=severe cardiopulmonary symptoms). A higher score indicated more severe symptoms experienced. Per protocol, change from baseline in the cardiopulmonary domain score at Week 24 was reported for DBPC period.
Change From Baseline in the Cognitive/Emotional Impacts Domain Score of PAH-SYMPACT® at Week 24Baseline and Week 24The PAH SYMPACT is a 23-item questionnaire to measure PAH-related symptoms and impact of PAH on daily life. The Cognitive/Emotional Impact domain consists of thinking clearly, feeling sad, feeling worried, and feeling frustrated. Participants were asked to recall and report on each item experienced in past 7 days. Score for each item ranges from 0 (not difficult at all) to 4 (extremely difficult). A domain score was calculated by summing the individual responses for each item and dividing by the number of impact items (range: 0=no cognitive/emotional impact to 4=severe cognitive/emotional impact). A higher score indicated more severe cognitive/emotional impact. Per protocol, change from baseline in the cognitive/emotional impacts domain score at Week 24 was reported for DBPC period.
Change From Baseline in the Physical Impacts Domain Score of Pulmonary Arterial Hypertension - Symptoms and Impact (PAH-SYMPACT®) at Week 24Baseline and Week 24The PAH SYMPACT is a 23-item questionnaire to measure pulmonary arterial hypertension (PAH)-related symptoms and impact of PAH on daily life. The physical impact domain consists of walking slowly on a flat surface, walking quickly on a flat surface, walking uphill, carrying things, doing light indoor household chores, washing, or dressing oneself, and needing help from others. Participants were asked to recall and report on each item experienced in past 7 days. Score for each item ranges from 0 (not difficult at all) to 4 (extremely difficult). A domain score was calculated by summing the individual responses for each item and dividing by the number of impact items (range: 0=no physical impact to 4=severe physical impact). A higher score indicated more severe physical impact. Per protocol, change from baseline in the physical impacts domain score at Week 24 was reported for DBPC period.
Change From Baseline in Pulmonary Vascular Resistance (PVR) at Week 24Baseline and Week 24PVR is a hemodynamic variable of pulmonary circulation and was measured by right heart catheterization (RHC). Per protocol, the change from baseline in PVR at Week 24 was reported for DBPC period.
Change From Baseline in NT-proBNP Levels at Week 24Baseline and Week 24NT-proBNP is a circulating biomarker that reflects myocardial stretch. Per protocol, the change from baseline in NT-proBNP level at Week 24 was reported for DBPC period.

Countries

Argentina, Australia, Belgium, Brazil, Canada, Czechia, France, Germany, Israel, Italy, Mexico, Netherlands, New Zealand, Poland, Serbia, South Korea, Spain, Sweden, Switzerland, United Kingdom, United States

Participant flow

Recruitment details

Of the 324 randomized participants, 1 participant was randomized in error and did not receive study treatment and no data was collected. Hence, the results are presented on 323 participants.

Pre-assignment details

Per protocol, not all participants from the double-blind placebo controlled (DBPC) period entered the long-term double blind (LTDB) period due to clinical worsening or consent withdrawal after DBPC period.

Participants by arm

ArmCount
Sotatercept Plus Background PAH Therapy
Participants received a starting dose of sotatercept 0.3 mg/kg titrated up to 0.7mg/kg by subcutaneous (SC) injection every 21 days plus background PAH therapy during the double-blind placebo controlled (DBPC) period for up to approximately 24 weeks. After 24 weeks, participants received sotatercept dose titrated up to 0.7mg/kg SC injection every 21 days plus background PAH therapy during the long-term double blind (LTDB) period for up to approximately 72 weeks.
163
Placebo Plus Background PAH Therapy
Participants received dose matched placebo by SC injection every 21 days plus background PAH therapy during the DBPC period for up to approximately 24 weeks and the LTDB period for up to approximately 72 weeks.
160
Total323

Withdrawals & dropouts

PeriodReasonFG000FG001
Double Blind Placebo Controlled (DBPC)Adverse Event11
Double Blind Placebo Controlled (DBPC)Clinical worsening event02
Double Blind Placebo Controlled (DBPC)Death05
Double Blind Placebo Controlled (DBPC)Protocol Violation11
Double Blind Placebo Controlled (DBPC)Withdrawal by Subject23
Long Term Double Blind (LTDB)Adverse Event20
Long Term Double Blind (LTDB)Death21
Long Term Double Blind (LTDB)Protocol Violation01
Long Term Double Blind (LTDB)Sponsor decision01
Long Term Double Blind (LTDB)Withdrawal by Subject03

Baseline characteristics

CharacteristicTotalPlacebo Plus Background PAH TherapySotatercept Plus Background PAH Therapy
6-Minute Walk Distance (6MWD) at baseline401.1 meters
STANDARD_DEVIATION 82.4
404.7 meters
STANDARD_DEVIATION 80.59
397.6 meters
STANDARD_DEVIATION 84.28
Age, Continuous47.9 Years
STANDARD_DEVIATION 14.79
48.3 Years
STANDARD_DEVIATION 15.5
47.6 Years
STANDARD_DEVIATION 14.09
Background PAH Therapy at Baseline
Double therapy
112 Participants56 Participants56 Participants
Background PAH Therapy at Baseline
Monotherapy
13 Participants4 Participants9 Participants
Background PAH Therapy at Baseline
Triple therapy
198 Participants100 Participants98 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
58 Participants31 Participants27 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
256 Participants124 Participants132 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
9 Participants5 Participants4 Participants
Race (NIH/OMB)
American Indian or Alaska Native
1 Participants1 Participants0 Participants
Race (NIH/OMB)
Asian
7 Participants6 Participants1 Participants
Race (NIH/OMB)
Black or African American
7 Participants5 Participants2 Participants
Race (NIH/OMB)
More than one race
11 Participants4 Participants7 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
1 Participants1 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
8 Participants2 Participants6 Participants
Race (NIH/OMB)
White
288 Participants141 Participants147 Participants
Sex: Female, Male
Female
256 Participants127 Participants129 Participants
Sex: Female, Male
Male
67 Participants33 Participants34 Participants
World Health Organization (WHO) functional class (FC) II or III at baseline
Class II
157 Participants78 Participants79 Participants
World Health Organization (WHO) functional class (FC) II or III at baseline
Class III
166 Participants82 Participants84 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
EG003
affected / at risk
deaths
Total, all-cause mortality
0 / 1636 / 1602 / 1591 / 142
other
Total, other adverse events
111 / 16388 / 16082 / 15850 / 142
serious
Total, serious adverse events
23 / 16336 / 16026 / 15814 / 142

Outcome results

Primary

Change From Baseline in 6-Minute Walk Distance (6MWD) at Week 24

The 6MWD was the distance walked in 6 minutes as a measure of functional capacity. This was assessed using the 6-minute walk test (6MWT). Per protocol, change from baseline in 6MWD at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and had a baseline value of 6MWD.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in 6-Minute Walk Distance (6MWD) at Week 2434.4 meters
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in 6-Minute Walk Distance (6MWD) at Week 241.0 meters
p-value: <0.00195% CI: [27.53, 54.14]Aligned Rank Stratified Wilcoxon (ARSW)
Primary

Number of Participants Who Discontinued Study Treatment Due to an AE

An AE was any untoward medical occurrence in a study participant administered a study drug, which did not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study drug whether or not it was considered related to the study drug. Per protocol, the number of participants who discontinued study treatment due to an AE were reported for DBPC period.

Time frame: Up to approximately 24 weeks

Population: All randomized participants who received at least one dose of study treatment.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Sotatercept Plus Background PAH Therapy (DBPC Period)Number of Participants Who Discontinued Study Treatment Due to an AE3 Participants
Placebo Plus Background PAH Therapy (DBPC Period)Number of Participants Who Discontinued Study Treatment Due to an AE10 Participants
Primary

Number of Participants Who Experienced an Adverse Event (AE)

An AE was any untoward medical occurrence in a study participant administered a study drug, which did not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study drug whether or not it was considered related to the study drug. Per protocol, the number of participants who reported an AE were reported for DBPC period.

Time frame: Up to approximately 24 weeks

Population: All randomized participants who received at least one dose of study treatment.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Sotatercept Plus Background PAH Therapy (DBPC Period)Number of Participants Who Experienced an Adverse Event (AE)138 Participants
Placebo Plus Background PAH Therapy (DBPC Period)Number of Participants Who Experienced an Adverse Event (AE)140 Participants
Secondary

Change From Baseline in NT-proBNP Levels at Week 24

NT-proBNP is a circulating biomarker that reflects myocardial stretch. Per protocol, the change from baseline in NT-proBNP level at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline measurement for the NT-proBNP levels.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in NT-proBNP Levels at Week 24-230.3 pg/mL
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in NT-proBNP Levels at Week 2458.6 pg/mL
p-value: <0.00195% CI: [-573.54, -309.61]ARSW test
Secondary

Change From Baseline in Percentage of Participants Who Maintain or Achieve a Low Risk Score Using the Simplified French Risk Score Calculator at Week 24

The simplified French risk scoring system was based on the 2015 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines for the diagnosis and treatment of pulmonary hypertension (PH). In this study, the noninvasive parameters were used to determine the score. 'Low risk' was defined as attaining or maintaining all 3 low-risk criteria: WHO FC I or II, 6MWD \> 440 m, and NT-proBNP \<300 ng/L. Per protocol, change from baseline in percentage of participants who maintained or achieved a low risk score using the simplified French risk score calculator at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline measurement for the low risk score.

ArmMeasureValue (NUMBER)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in Percentage of Participants Who Maintain or Achieve a Low Risk Score Using the Simplified French Risk Score Calculator at Week 2439.5 Percent Change
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in Percentage of Participants Who Maintain or Achieve a Low Risk Score Using the Simplified French Risk Score Calculator at Week 2418.2 Percent Change
p-value: <0.001Cochran-Mantel-Haenszel
Secondary

Change From Baseline in Pulmonary Vascular Resistance (PVR) at Week 24

PVR is a hemodynamic variable of pulmonary circulation and was measured by right heart catheterization (RHC). Per protocol, the change from baseline in PVR at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline measurement for the PVR.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in Pulmonary Vascular Resistance (PVR) at Week 24-165.1 dynes*sec/cm^5
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in Pulmonary Vascular Resistance (PVR) at Week 2432.8 dynes*sec/cm^5
p-value: <0.00195% CI: [-288.37, -180.75]ARSW test
Secondary

Change From Baseline in the Cardiopulmonary Symptoms Domain Score of PAH-SYMPACT® at Week 24

The PAH SYMPACT is a 23-item questionnaire to measure PAH-related symptoms and impact of PAH on daily life. The cardiopulmonary symptoms consist of shortness of breath, fatigue, lack of energy, swelling in the ankles or legs, swelling in the stomach area, and cough. Participants were asked to recall and report on each item experienced in past 7 days. Score for each item ranges from 0 (no symptom at all) to 4 (very severe symptoms). The mean individual symptom item score was determined for each of the 6 items and a domain score was calculated by summing the mean individual symptom item scores and dividing by the number of items (range: 0=no cardiopulmonary symptoms to 4=severe cardiopulmonary symptoms). A higher score indicated more severe symptoms experienced. Per protocol, change from baseline in the cardiopulmonary domain score at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline cardiopulmonary domain score.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Cardiopulmonary Symptoms Domain Score of PAH-SYMPACT® at Week 24-0.12 Score on a scale
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Cardiopulmonary Symptoms Domain Score of PAH-SYMPACT® at Week 24-0.01 Score on a scale
p-value: 0.02895% CI: [-0.256, -0.014]ARSW test
Secondary

Change From Baseline in the Cognitive/Emotional Impacts Domain Score of PAH-SYMPACT® at Week 24

The PAH SYMPACT is a 23-item questionnaire to measure PAH-related symptoms and impact of PAH on daily life. The Cognitive/Emotional Impact domain consists of thinking clearly, feeling sad, feeling worried, and feeling frustrated. Participants were asked to recall and report on each item experienced in past 7 days. Score for each item ranges from 0 (not difficult at all) to 4 (extremely difficult). A domain score was calculated by summing the individual responses for each item and dividing by the number of impact items (range: 0=no cognitive/emotional impact to 4=severe cognitive/emotional impact). A higher score indicated more severe cognitive/emotional impact. Per protocol, change from baseline in the cognitive/emotional impacts domain score at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline cognitive/emotional impacts domain score.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Cognitive/Emotional Impacts Domain Score of PAH-SYMPACT® at Week 240.00 Score on a scale
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Cognitive/Emotional Impacts Domain Score of PAH-SYMPACT® at Week 240.000007 Score on a scale
p-value: 0.15695% CI: [-0.399, 0.084]ARSW test
Secondary

Change From Baseline in the Percentage of Participants Achieving Multicomponent Improvement at Week 24

Multicomponent Improvement was defined as consisting of all of the following: (a) Improvement in 6MWD (increase ≥30 meters) (b) Improvement in N-terminal pro b-type natriuretic peptide (NT-proBNP; decrease in NT-proBNP ≥30%) or maintenance/achievement of NT-proBNP level \<300 ng/L (c) Improvement in World Health Organization (WHO) Functional Class (FC) or maintenance of WHO FC II. Per protocol, change from baseline in the percentage of participants achieving multicomponent improvement at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline measurement for the multicomponent improvement.

ArmMeasureValue (NUMBER)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Percentage of Participants Achieving Multicomponent Improvement at Week 2438.9 Percent change
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Percentage of Participants Achieving Multicomponent Improvement at Week 2410.1 Percent change
p-value: <0.001Cochran-Mantel-Haenszel
Secondary

Change From Baseline in the Percentage of Participants Who Improve in WHO FC at Week 24

The severity of participant's pulmonary arterial hypertension (PAH) symptoms will be graded using the WHO FC system. WHO functional classification for PAH ranges 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). Participants who improve in WHO FC were classified into Improved, No change and Worsened. Improvement = reduction in FC, worsened = increase in FC and no change = no change in FC. Per protocol, change from baseline in the percentage of participants who improve in WHO FC at Week 24 were reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline measurement for the WHO FC.

ArmMeasureValue (NUMBER)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Percentage of Participants Who Improve in WHO FC at Week 2429.4 Percent change
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Percentage of Participants Who Improve in WHO FC at Week 2413.8 Percent change
p-value: <0.001Cochran-Mantel-Haenszel
Secondary

Change From Baseline in the Physical Impacts Domain Score of Pulmonary Arterial Hypertension - Symptoms and Impact (PAH-SYMPACT®) at Week 24

The PAH SYMPACT is a 23-item questionnaire to measure pulmonary arterial hypertension (PAH)-related symptoms and impact of PAH on daily life. The physical impact domain consists of walking slowly on a flat surface, walking quickly on a flat surface, walking uphill, carrying things, doing light indoor household chores, washing, or dressing oneself, and needing help from others. Participants were asked to recall and report on each item experienced in past 7 days. Score for each item ranges from 0 (not difficult at all) to 4 (extremely difficult). A domain score was calculated by summing the individual responses for each item and dividing by the number of impact items (range: 0=no physical impact to 4=severe physical impact). A higher score indicated more severe physical impact. Per protocol, change from baseline in the physical impacts domain score at Week 24 was reported for DBPC period.

Time frame: Baseline and Week 24

Population: All randomized participants who received at least one dose of study treatment and who had a baseline physical impact domain score.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Physical Impacts Domain Score of Pulmonary Arterial Hypertension - Symptoms and Impact (PAH-SYMPACT®) at Week 24-0.13 Score on a scale
Placebo Plus Background PAH Therapy (DBPC Period)Change From Baseline in the Physical Impacts Domain Score of Pulmonary Arterial Hypertension - Symptoms and Impact (PAH-SYMPACT®) at Week 240.01 Score on a scale
p-value: 0.0195% CI: [-0.49, -0.04]ARSW test
Secondary

Time to Death or the First Occurrence of Clinical Worsening Event

Clinical Worsening events are defined as any of the following: worsening-related listing for lung and/or heart transplant; need to initiate rescue therapy with an approved background PAH therapy or the need to increase the dose of infusion prostacyclin by 10% or more; need for atrial septostomy; hospitalization for worsening of PAH (≥ 24 hours); or deterioration of PAH defined by both of the following events occurring at any time: worsened WHO FC and decrease in 6MWD by ≥15% confirmed by 2 tests at least 4 hours apart, but no more than 1 week. Per protocol, time to death or the first occurrence of clinical worsening event was reported.

Time frame: Up to approximately 18 months

Population: All randomized participants who received at least one dose of study treatment and who died or experienced a first clinical worsening event.

ArmMeasureValue (MEDIAN)
Sotatercept Plus Background PAH Therapy (DBPC Period)Time to Death or the First Occurrence of Clinical Worsening EventNA Weeks
Placebo Plus Background PAH Therapy (DBPC Period)Time to Death or the First Occurrence of Clinical Worsening EventNA Weeks
p-value: <0.00195% CI: [0.076, 0.347]Log Rank

Source: ClinicalTrials.gov · Data processed: Jun 6, 2026