Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy ((EXPLORER-HCM))

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT03470545
Recruitment Status : Recruiting
First Posted : March 20, 2018
Last Update Posted : October 18, 2018
Information provided by (Responsible Party):
MyoKardia, Inc.

Brief Summary:
This is a multicenter, international, double-blind study of the administration of mavacamten in participants with symptomatic obstructive HCM (oHCM). Approximately 220 participants will be randomized to receive placebo or mavacamten.

Condition or disease Intervention/treatment Phase
Obstructive Hypertrophic Cardiomyopathy Drug: mavacamten Drug: Placebo Phase 3

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 220 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Randomized, Double Blind, Placebo Controlled Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy
Actual Study Start Date : May 29, 2018
Estimated Primary Completion Date : June 2020
Estimated Study Completion Date : June 2020

Arm Intervention/treatment
Experimental: mavacamten (MYK-461) Drug: mavacamten
mavacamten capsules
Other Name: MYK-461

Placebo Comparator: Placebo Drug: Placebo
placebo oral capsule

Primary Outcome Measures :
  1. Percentage of Participants Achieving A Clinical Response [ Time Frame: 30 weeks ]
    A positive clinical response (value="YES") is defined as having an improvement in symptom severity from baseline to Week 30 as assessed by New York Heart Association (NYHA) functional classification (e.g. I, II, III, or IV) and increase in exercise capacity from baseline to Week 30 as assessed by measurement of peak oxygen consumption (pVO2) (e.g. mL/min/kg) determined by cardiopulmonary exercise testing (CPET).

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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 Screening
  • 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 β-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 6 months prior to Screening or planned ICD placement during the study
  • 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

Information from the National Library of Medicine

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 identifier (NCT number): NCT03470545

Contact: MyoKardia Medical Information Team (650) 741-0900

United States, Arizona
Mayo Clinic Arizona Recruiting
Scottsdale, Arizona, United States, 85259
Principal Investigator: Steven Lester, MD         
United States, California
UCSF School of Medicine Recruiting
San Francisco, California, United States, 94143
Principal Investigator: Theodore Abraham, MD         
Stanford University Recruiting
Stanford, California, United States, 94305
Principal Investigator: Matthew Wheeler, MD         
United States, Connecticut
Yale New Haven Hospital Recruiting
New Haven, Connecticut, United States, 16511
Principal Investigator: Daniel Jacoby, MD         
United States, Massachusetts
Brigham and Women's Hospital Recruiting
Boston, Massachusetts, United States, 02115
Principal Investigator: Neal Lakdawala, MD         
United States, Michigan
University of Michigan Recruiting
Ann Arbor, Michigan, United States, 48109
Principal Investigator: Sara Saberi, MD         
United States, Missouri
Washington University School of Medicine Recruiting
Saint Louis, Missouri, United States, 63110
Principal Investigator: Richard Bach, MD         
United States, New York
NYU Langone Medical Center Recruiting
New York, New York, United States, 10017
Principal Investigator: Mark Sherrid, MD         
United States, North Carolina
Carolinas Medical Center Recruiting
Charlotte, North Carolina, United States, 28203
Principal Investigator: John Symanski, MD         
Duke Cardiology at Southpoint Recruiting
Durham, North Carolina, United States, 27710
Principal Investigator: Andrew Wang, MD         
United States, Ohio
Cincinnati Children's Hospital Medical Center Recruiting
Cincinnati, Ohio, United States, 45229
Principal Investigator: Richard Becker, MD         
United States, Oregon
Oregon Health & Science University Recruiting
Portland, Oregon, United States, 97239
Principal Investigator: Stephen Heitner, MD         
United States, Pennsylvania
St. Luke's Cardiology Associates Recruiting
Bethlehem, Pennsylvania, United States, 18018
Principal Investigator: Jamshid Shirani, MD         
University of Pennsylvania (Penn Heart and Vascular Center) Recruiting
Philadelphia, Pennsylvania, United States, 19104
Principal Investigator: Anjali T Owens, MD         
University of Pittsburgh Medical Center Presbyterian Recruiting
Pittsburgh, Pennsylvania, United States, 15213
Principal Investigator: Timothy Wong, MD         
United States, Texas
University of Texas Southwestern Medical Center Recruiting
Dallas, Texas, United States, 75235
Principal Investigator: Aslan Turer, MD         
Houston Methodist Hospital Recruiting
Houston, Texas, United States, 77030
Principal Investigator: Sherif Nagueh, MD         
University of Texas Houston Medical School Recruiting
Houston, Texas, United States, 77030
Principal Investigator: Ali Marian, MD         
Sponsors and Collaborators
MyoKardia, Inc.
Study Director: Amy Sehnert, MD Medical Monitor

Responsible Party: MyoKardia, Inc. Identifier: NCT03470545     History of Changes
Other Study ID Numbers: MYK-461-005
First Posted: March 20, 2018    Key Record Dates
Last Update Posted: October 18, 2018
Last Verified: October 2018

Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by MyoKardia, Inc.:
Symptomatic, left ventricular outflow tract gradient

Additional relevant MeSH terms:
Cardiomyopathy, Hypertrophic
Heart Diseases
Cardiovascular Diseases
Pathological Conditions, Anatomical
Aortic Stenosis, Subvalvular
Aortic Valve Stenosis
Heart Valve Diseases