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Note: This record shows only 22 elements of the WHO Trial Registration Data Set. To view changes that have been made to the source record, or for additional information about this trial, click on the URL below to go to the source record in the primary register.
Last refreshed on: 12 December 2020
Main ID:  NCT03470545
Date of registration: 12/03/2018
Prospective Registration: Yes
Primary sponsor: MyoKardia, Inc.
Public title: Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy EXPLORER-HCM
Scientific title: A Randomized, Double Blind, Placebo Controlled Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy
Date of first enrolment: May 29, 2018
Target sample size: 251
Recruitment status: Completed
Study type:  Interventional
Study design:  Allocation: Randomized. Intervention model: Parallel Assignment. Primary purpose: Treatment. Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor).  
Phase:  Phase 3
Countries of recruitment
Belgium Czechia Denmark France Germany Israel Italy Netherlands
Poland Portugal Spain United Kingdom United States
Name:     Medical Information Team
Affiliation:  MyoKardia, Inc.
Key inclusion & exclusion criteria

Key Inclusion Criteria:

- Age 18 and greater, body weight = 45kg

- Has adequate acoustic windows to enable accurate transthoracic echocardiograms (TTEs)

- Diagnosed with oHCM consistent with current American College of Cardiology
Foundation/American Heart Association and European Society of Cardiology guidelines
and satisfy both criteria:

- Has documented left ventricular ejection fraction (LVEF) =55%

- NYHA Class II or III

- Has documented oxygen saturation at rest =90% at Screening

- Is able to perform an upright CPET and has a respiratory exchange ratio (RER) =1.0 at
Screening per central reading

Key Exclusion Criteria:

- Known infiltrative or storage disorder causing cardiac hypertrophy that mimics oHCM,
such as Fabry disease, amyloidosis, or Noonan syndrome with LV hypertrophy

- History of syncope or sustained ventricular tachyarrhythmia with exercise within 6
months prior to Screening

- History of resuscitated sudden cardiac arrest (at any time) or known history of
appropriate implantable cardioverter defibrillator (ICD) discharge for
life-threatening ventricular arrhythmia within 6 months prior to Screening

- Paroxysmal, intermittent atrial fibrillation with atrial fibrillation present at

- Persistent or permanent atrial fibrillation not on anticoagulation for at least 4
weeks prior to Screening and/or not adequately rate controlled within 6 months prior
to Screening

- Treatment (within 14 days prior to Screening) or planned treatment during the study
with disopyramide or ranolazine

- Treatment (within 14 days prior to Screening) or planned treatment during the study
with a combination of ß-blockers and calcium channel blockers

- LVOT gradient with Valsalva maneuver <30 mmHg at Screening

- Has been successfully treated with invasive septal reduction (surgical myectomy or
percutaneous alcohol septal ablation [ASA]) within 6 months prior to Screening or
plans to have either of these treatments during the study

- ICD placement within 2 months prior to Screening or planned ICD placement during the

- Has a history or evidence of any other clinically significant disorder, condition, or
disease that, in the opinion of the investigator, would pose a risk to participant
safety or interfere with the study evaluation, procedures, or completion

- Prior treatment with cardiotoxic agents such as doxorubicin or similar

Age minimum: 18 Years
Age maximum: N/A
Gender: All
Health Condition(s) or Problem(s) studied
Obstructive Hypertrophic Cardiomyopathy
Drug: mavacamten
Drug: Placebo
Primary Outcome(s)
Percentage of Participants Achieving A Clinical Response [Time Frame: 30 weeks]
Secondary Outcome(s)
Secondary ID(s)
Source(s) of Monetary Support
Please refer to primary and secondary sponsors
Secondary Sponsor(s)
Ethics review
Results available:
Date Posted:
Date Completed:
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