Clinical Study to Assess the Efficacy, Safety and Tolerability of Macitentan in Subjects With Inoperable Chronic Thromboembolic Pulmonary Hypertension (MERIT-1)
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ClinicalTrials.gov Identifier: NCT02021292 |
Recruitment Status :
Completed
First Posted : December 27, 2013
Results First Posted : January 23, 2018
Last Update Posted : June 4, 2020
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Condition or disease | Intervention/treatment | Phase |
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Chronic Thromboembolic Pulmonary Hypertension | Drug: Macitentan Drug: Placebo | Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 80 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | Prospective, Randomized, Placebo-controlled, Double-blind, Multicenter, Parallel-group, 24-week Study to Assess the Efficacy, Safety and Tolerability of Macitentan in Subjects With Inoperable Chronic Thromboembolic Pulmonary Hypertension |
Actual Study Start Date : | August 20, 2014 |
Actual Primary Completion Date : | September 28, 2016 |
Actual Study Completion Date : | September 28, 2016 |

Arm | Intervention/treatment |
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Experimental: Macitentan
Macitentan 10 mg, oral tablet, to be taken once daily.
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Drug: Macitentan
Macitentan 10 mg, oral tablet, to be taken once daily.
Other Name: ACT-064992 |
Placebo Comparator: Placebo
Matching placebo oral tablet, to be taken once daily.
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Drug: Placebo
Matching placebo oral tablet, to be taken once daily. |
- Change From Baseline to Week 16 in Pulmonary Vascular Resistance (PVR) at Rest. [ Time Frame: From baseline to Week 16 ]The primary efficacy endpoint is defined as the PVR at rest at Week 16 expressed as percent of baseline PVR at rest.
- Change From Baseline to Week 24 in Exercise Capacity, as Measured by the 6-minute Walk Distance (6MWD). [ Time Frame: From baseline to Week 24 ]The purpose of the six minute walk is to test exercise tolerance and capacity. The test measures the distance an individual is able to walk over a total of six minutes on a hard, flat surface. The goal is for the individual to walk as far as possible in six minutes.
- Change From Baseline to Week 24 in Borg Dyspnea Index Collected at the End of the 6-minute Walk Test (6MWT). [ Time Frame: From baseline to Week 24 ]This outcome measures the difference in the Borg dyspnea index collected at the end of the 6-minute walk test (6MWT) at Week 24 compared to baseline. The Borg dyspnea index rates the severity of dyspnea (difficult or labored breathing) on a scale from 0 ('Nothing at all') to 10 ('Very, very severe - maximal'). A decrease in the Borg dyspnea index indicates an improvement.
- Proportion of Subjects With Worsening in WHO Functional Class (FC) From Baseline to Week 24 [ Time Frame: From baseline to Week 24 ]WHO functional classes are defined as follows: 1) class I: no symptoms with exercise or at rest. No limitation of activity. 2) class II: No symptoms at rest but slight limitation with ordinary activities causing symptoms (e.g. short of breath with climbing a flight of stairs, grocery shopping, or making the bed). 3) class III: may not have symptoms at rest but activities greatly limited by shortness of breath, fatigue, or near fainting. 4) class IV: symptoms at rest (such as dyspnea and/or fatigue) and inability to carry out any physical activity without symptoms (e.g. may faint especially while bending over with their heads lowered). Patients in class IV manifest signs of right heart failure. Shifting to a higher class (e.g. from class III to class IV) represents a 'worsening' while shifting to a lower class (e.g. from class III to class II) means an 'improvement'.

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Ages Eligible for Study: | 18 Years to 84 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Written informed consent
- Subject with CTEPH (WHO Group 4) judged as inoperable due to the localization of the obstruction being surgically inaccessible (i.e., distal disease).
- Female of childbearing potential must have a negative pre-treatment serum pregnancy test, be advised on appropriate methods of contraception, and agree to use 2 reliable methods of contraception.
Exclusion Criteria:
- Previous pulmonary endarterectomy.
- Recurrent thromboembolism despite sufficient oral anticoagulants.
- Symptomatic acute pulmonary embolism in the 6-month period prior to randomization.
- Known moderate-to-severe restrictive lung disease (i.e., TLC < 60% of predicted value) or obstructive lung disease (i.e., FEV1 < 70% of predicted, with FEV1/FVC < 65%) or known significant chronic lung disease diagnosed by chest imaging (e.g., interstitial lung disease, emphysema).
- Acute or chronic conditions (other than dyspnea) that limit the ability to comply with study requirements in the 3-month period prior to Screening visit or during the Screening period.

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): NCT02021292

Study Chair: | Kelly Papadakis, MD | Actelion |
Responsible Party: | Actelion |
ClinicalTrials.gov Identifier: | NCT02021292 |
Other Study ID Numbers: |
AC-055E201 |
First Posted: | December 27, 2013 Key Record Dates |
Results First Posted: | January 23, 2018 |
Last Update Posted: | June 4, 2020 |
Last Verified: | May 2020 |
Chronic thromboembolic pulmonary hypertension (CTEPH) |
Hypertension, Pulmonary Hypertension Vascular Diseases Cardiovascular Diseases Lung Diseases Respiratory Tract Diseases |
Macitentan Endothelin A Receptor Antagonists Endothelin Receptor Antagonists Molecular Mechanisms of Pharmacological Action Endothelin B Receptor Antagonists |