This week in the journal Annals of Internal Medicine, MyoKardia reported positive results from its open label phase 2 clinical trial of its drug mavacamten (formerly known as MYK-461) for obstructive hypertrophic cardiomyopathy. The study was conducted at 5 HCM centers and enrolled 21 subjects with obstructive HCM. All subjects saw some degree of improvement to their condition after taking mavacamten.
There were two groups of patients enrolled in the study: The first group of patients took only mavacamten, while the second group continued on a beta-blocker while also taking mavacamten.
The group of patients taking only mavacamten saw their post-exercise left ventricular outflow tract gradient fall from an average of 103 mm HG to an average of 19 mmHG after 12 weeks, with their left ventricular ejection fraction reduced by about 15%. Peak Vo2 measurements increased by an average of 3.5 mL/kg/min.
The group of patients taking beta blockers along with mavacamten saw more modest improvements, with their post exercise left ventricular outflow tract gradient falling from an average of 86 mmHG to 64 mmHG, with the average left ventricular ejection fraction falling 6%. Peak Vo2 measurements increased an average of 1.7 mL/kg/min.
The study found that shortness of breath was improved in both group of patients.
While the drug was well tolerated, the the most common side effects were decreased ejection fraction at higher doses and atrial fibrillation.
See previous stories about this drug here on HCMBeat:
DISCLOSURES: HCMBEAT HAS RECEIVED UNRESTRICTED EDUCATIONAL GRANTS FROM MYOKARDIA. ADDITIONALLY, CYNTHIA BURSTEIN WALDMAN OF HCMBEAT SERVES AS A PATIENT ADVISOR ON THE STEERING COMMITTEE FOR MYOKARDIA’S EXPLORER TRIAL.