MyoKardia, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to mavacamten, a novel, oral, allosteric modulator of cardiac myosin, for the treatment of symptomatic, obstructive hypertrophic cardiomyopathy (HCM). The FDA's Breakthrough Therapy Designation is intended to expedite the development and review of a drug candidate that is planned for use to treat a serious or life-threatening disease or condition when clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints. In May, MyoKardia announced topline results from the company’s pivotal Phase 3 EXPLORER clinical trial of mavacamten for the treatment of symptomatic patients with obstructive HCM. Mavacamten was well tolerated, with a safety profile comparable to placebo, and demonstrated a robust treatment effect, with patients experiencing clinically meaningful responses to treatment, including reductions in symptoms, improvements in cardiac function and reduction or elimination of the obstruction of the left ventricle. MyoKardia is currently preparing a New Drug Application (NDA) for mavacamten, with plans to submit to the FDA in the first quarter of 2021.