Mr. Kirk sold his portion for $65 million in cash. He then founded New River Pharmaceuticals in the mid-90s, and became CEO in 2001. He sold the company for $2.6 billion in 2007. He then launched a management investment firm, and another pharmaceutical company, called Clinical Data. He sold Clinical Data for $2.1 billion in 2011. He is currently focused on his new company, Intrexon.