A Study of Sotatercept in Participants With PAH WHO FC III or FC IV at High Risk of Mortality (ZENITH)
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ClinicalTrials.gov Identifier: NCT04896008 |
Recruitment Status :
Recruiting
First Posted : May 21, 2021
Last Update Posted : June 13, 2022
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Condition or disease | Intervention/treatment | Phase |
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Pulmonary Arterial Hypertension | Drug: Sotatercept Other: Placebo | Phase 3 |
Study A011-14 is a Phase 3, randomized, double-blind, placebo-controlled study to evaluate sotatercept when added to maximum tolerated background PAH therapy on time to first event of all-cause death, lung transplantation, or PAH worsening related hospitalization of ≥ 24 hours, in participants with WHO FC IV PAH or WHO FC III PAH at high risk of mortality.
Participants with symptomatic PAH (WHO FC III or FC IV at high risk of mortality) 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 defect. Participants must have a Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) Lite 2 risk score of ≥ 10 and be on maximum tolerated combination background PAH therapy.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 166 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Each eligible participant will be randomized in a 1:1 ratio to 1 of the following 2 treatment arms during the DBPC Treatment Period:
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Masking: | Triple (Participant, Care Provider, Investigator) |
Primary Purpose: | Treatment |
Official Title: | A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate Sotatercept When Added to Maximum Tolerated Background Therapy in Participants With Pulmonary Arterial Hypertension (PAH) World Health Organization (WHO) Functional Class (FC) III or FC IV at High Risk Mortality |
Actual Study Start Date : | October 13, 2021 |
Estimated Primary Completion Date : | November 30, 2025 |
Estimated Study Completion Date : | December 31, 2026 |

Arm | Intervention/treatment |
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Placebo Comparator: Placebo plus background PAH therapy
Placebo administered subcutaneously (SC) every 21 days plus background PAH therapy
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Other: Placebo
Placebo |
Experimental: Sotatercept plus background PAH therapy
Sotatercept at a starting dose of 0.3 mg/kg, with a target dose of 0.7 mg/kg, SC every 21 days plus background PAH therapy
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Drug: Sotatercept
Sotatercept (ACE-011) is a recombinant fusion protein consisting of the extracellular domain of the human activin receptor type IIA linked to the Fc piece of human IgG1.
Other Name: ACE-011 |
- Time to first confirmed morbidity or mortality event. [ Time Frame: From randomization to first event, up to approximately 46 months. ]Events are defined as all-cause death, lung transplantation, or PAH worsening-related hospitalization of ≥ 24 hours. All events will be adjudicated by a blinded, independent committee of clinical experts.
- Overall survival [ Time Frame: Through study completion, estimated up to 46 months ]Time from randomization to death from any cause.
- Transplant-free survival. [ Time Frame: Through study completion, estimated up to 46 months ]Time from randomization to lung transplantation or death from any cause.
- Proportion of participants who experienced a mortality event. [ Time Frame: Through study completion, estimated up to 46 months ]Death from any cause is tracked throughout the study.
- Change from baseline in REVEAL Lite 2 risk score. [ Time Frame: From screening to Week 24. ]REVEAL Lite 2 risk score in each participant was measured at Week 24 versus baseline.
- Proportion of participants achieving a low or intermediate (≤ 7) REVEAL Lite 2 risk score at Week 24. [ Time Frame: From screening to Week 24. ]REVEAL Lite 2 risk score in each participant was measured at Week 24.
- Change from baseline in NT-proBNP levels. [ Time Frame: From screening to Week 24. ]NT-proBNP was measured at baseline and Week 24.
- Change from baseline in mean pulmonary artery pressure (mPAP) at Week 24. [ Time Frame: From screening to Week 24. ]mPAP was measured by right heart catheterization (RHC) during screening and Week 24.
- Change from baseline in pulmonary vascular resistance (PVR). [ Time Frame: From screening to Week 24. ]PVR is a hemodynamic variable measured by RHC during screening and Week 24.
- Proportion of participants who improve in WHO FC. [ Time Frame: From randomization to the end of the double-blind, placebo-controlled (DBPC) treatment period (EOT). ]The severity of an individual's PAH symptoms was graded using the WHO FC system at baseline and at the end of treatment (EOT).
- Change from baseline in 6MWD. [ Time Frame: From randomization to Week 24. ]6-minute walk test is a clinical exercise test to assess the functional capacity. 6MWD at baseline and Week 24 were measured.
- Change from baseline in cardiac output (CO) at Week 24. [ Time Frame: From screening to Week 24. ]CO is a component of the PVR calculation, and reduced CO reflects increased risk of morbidity and mortality.
- Change from baseline in EuroQoL-5 dimensions scale 5 levels (EQ-5D-5L) index score at Week 24. [ Time Frame: From randomization to Week 24. ]EQ 5D 5L index score measures health-related quality of life states in adults. The EQ 5D 5L questionnaire is designed for self-completion and captures information directly from the respondent. EQ 5D 5L index scores at baseline and Week 24 were measured.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years to 75 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
Eligible participants must meet all of the following inclusion criteria to be enrolled in the study:
- Age 18 to 75 years, inclusive
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Documented diagnostic right heart catheterization prior to screening confirming the diagnosis of WHO PAH Group 1 in any of the following subtypes:
- Idiopathic PAH
- Heritable PAH
- Drug/toxin-induced PAH
- PAH associated with CTD
- PAH associated with simple, congenital systemic to pulmonary shunts at least 1 year following repair
- Symptomatic PAH classified as WHO FC III or IV
- REVEAL Lite 2 risk score of ≥ 10
- Right heart catheterization performed during screening (or within 2 weeks prior to screening, if done at the clinical study site) documenting a minimum PVR of ≥ 5 Wood units and a pulmonary capillary wedge pressure (PCWP) or left ventricular end-diastolic pressure (LVEDP) of ≤ 15 mmHg
- Clinically stable and on stable doses of maximum tolerated (per investigator's judgment) double or triple background PAH therapies for at least 30 days prior to screening
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Females of childbearing potential must:
- Have 2 negative urine or serum pregnancy tests as verified by the investigator prior to starting study therapy; must agree to ongoing urine or serum pregnancy testing during the course of 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
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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
Exclusion Criteria:
- Diagnosis of PAH WHO Groups 2, 3, 4, or 5
- Diagnosis of the following PAH Group 1 subtypes: human immunodeficiency virus-associated PAH and PAH associated with portal hypertension
- Diagnosis of pulmonary veno-occlusive diseases or pulmonary capillary hemangiomatosis or overt signs of capillary and/or venous involvement
- Hemoglobin at screening above gender-specific upper limit of normal (ULN), per local laboratory test
- Baseline platelet count < 50,000/mm3 (< 50.0 x 109/L) at screening
- Baseline systolic blood pressure < 85 mmHg at screening
- Pregnant or breastfeeding women
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Any of the following clinical laboratory values at the Screening Visit:
- Estimated glomerular filtration rate < 30 mL/min/m2 (as defined by the Modification of Diet in Renal Disease Study equation)
- Serum alanine aminotransferase or aspartate aminotransferase levels > 3 × ULN or total bilirubin > 2.0 × ULN
- 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 or known allergic reaction to sotatercept (ACE 011) or luspatercept (ACE-536)
- History of pneumonectomy
- Pulmonary function test values of forced vital capacity < 60% predicted within 1 year prior to the Screening Visit
- Untreated obstructive sleep apnea
- History of known pericardial constriction
- History of restrictive or congestive cardiomyopathy
- Electrocardiogram (ECG) with Fridericia's corrected QT interval (QTcF) > 450 ms (or > 500 ms if right bundle branch block is present) during the Screening Period
- Personal or family history of long QT syndrome or sudden cardiac death
- Left ventricular ejection fraction < 50% on historical echocardiogram within 1 year prior to the Screening Visit
- Any current or prior history of symptomatic coronary disease (prior myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft surgery, or cardiac anginal chest pain) in the past 6 months prior to the Screening Visit
- Cerebrovascular accident within 3 months prior to the Screening Visit
- Significant (≥ 2+ regurgitation) mitral regurgitation or aortic regurgitation valvular disease

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04896008
Contact: Toll Free Number | 1-888-577-8839 | Trialsites@merck.com |

Study Director: | Medical Director | Merck Sharp & Dohme LLC |
Responsible Party: | Acceleron Pharma Inc. |
ClinicalTrials.gov Identifier: | NCT04896008 |
Other Study ID Numbers: |
7962-006 A011-14 ( Other Identifier: Acceleronpharma ) 2020-005061-13 ( EudraCT Number ) |
First Posted: | May 21, 2021 Key Record Dates |
Last Update Posted: | June 13, 2022 |
Last Verified: | June 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | http://engagezone.msd.com/doc/ProcedureAccessClinicalTrialData.pdf |
URL: | http://engagezone.msd.com/ds_documentation.php |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Pulmonary, hypertension, sotatercept |
Pulmonary Arterial Hypertension Familial Primary Pulmonary Hypertension Hypertension Vascular Diseases |
Cardiovascular Diseases Hypertension, Pulmonary Lung Diseases Respiratory Tract Diseases |