Mast Therapeutics posts enormous gain

|By:, SA News Editor

Mast Therapeutics (MSTX) — which got some traction earlier this month after saying MST-188 "demonstrated a statistically significant improvement in numerous parameters of heart function," in a nonclinical heart failure model — closes the day with a 57% gain.

Earlier, a trader purchased some 4K July $1 calls — volume in that strike was triple the existing open interest, according to OptionMonster.