Pharmaceutical giant Roche will buy New York City-based Flatiron Health. The Swiss company will pay $1.9 billion for Flatiron, adding to its existing stake of 12.6 percent in the startup. That makes the whole shebang worth about $2.1 billion, according to CNBC. Officials expect the deal to close in the first half of this year. Flatiron Health was founded in 2012 by Nat Turner and Zach Weinberg, two young entrepreneurs who sold their ad-tech company, Invite Media, to Google in 2010.