ENTA's CEO Jay Luly exercised and held 250,000 options—about $8M worth of stock—on 1/10/14 (last Friday, the same day as the 8-K filing about the BoD resignations):
That Luly is holding the execised shares rather than selling them is quite bullish, of course. (The options in question did not expire until Jul and Dec 2014.)
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”