What happened

Shares of MyoKardia (NASDAQ:MYOK) climbed 62.8% in May, according to data provided by S&P Global Market Intelligence, after the company said its investigational heart drug met primary and secondary endpoints in a phase 3 clinical trial.

A researcher notes trial data on a clipboard while a patient watches.

Image source: Getty Images.

Mavacamten is a treatment for obstructive hypertrophic cardiomyopathy (HCM), a chronic and progressive disease of the heart that results in reduced pumping capacity. In the phase 3 trial, the primary endpoint was a functional analysis that measured the drug's performance relative to placebo on symptoms and cardiac function. The secondary endpoints involved measures of shortness of breath, post-exercise left ventricular outflow, and characteristics associated with heart failure. Mavacamten resulted in statistically significant improvement across the board, and the drug was also well tolerated by patients.

So what

At the moment, HCM treatment options are limited. Doctors try to control the disease with beta blockers, antiarrythmic drugs, and other therapies to reduce symptoms. Analysts have predicted peak sales in the range of $1.5 billion to more than $2 billion for mavacamten in the treatment of HCM.

Mavacamten also may work in other indications in need of more therapies. MyoKardia is studying the drug for non-obstructive HCM and in March reported favorable phase 2 data for that indication. Plans are in the works for a proof-of-concept study in a targeted subgroup of patients with heart failure with preserved ejection fraction. In that condition, the heart is unable to pump enough blood into the body.

Now what

The biotech company will submit mavacamten for the treatment of obstructive HCM to the U.S. Food and Drug Administration (FDA) for review early next year. If approved, it would be MyoKardia's first commercialized product.

Though MyoKardia's shares have posted major gains in a short period of time, any positive news from other trials of mavacamten may push them higher. And a possible regulatory victory next year may result in gains further down the road.

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