 Shares of MyoKardia NASDAQ: MYOK climbed 62.8 in May, according to data provided by SP; Global Market Intelligence, after the company said its investigational heart drug met primary and secondary endpoints in a phase 3 clinical trial. 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 drugs performance relative to placebo on symptoms and cardiac function. 