If you had checked yahoo finance or nadaq.com, you would know he executed options:
HECHT PETER M Officer: 03/17/2015 Sell direct 125,000 at $15.6100, 4,141,417 shares owned post transaction HECHT PETER M Officer 03/17/2015 Option Execute direct 125,000 at $1.5600, 4,266,417 shares owned post transaction
option price executed was $1.56, so those are evidently pretty old, pre-IPO options that probably came up on their expiration date.
As for share ownership (s. above, >4 million shares): to put it in perspective, the CEO of IRWD owns more shares than 141 of the 150 institutional investors in IRWD, compare:
I would encourage you to look up the CEO salaries for the CEO of IRWD, a company with a (profitable) product on the market, and the CEO of SGYP, a company with no FDA approved product, in the relevant SEC filings.