Forest Laboratories has entered into a definitive agreement to acquire Aptalis, a privately held U.S.-based specialty pharma focused on gastrointestinal and cystic fibrosis tretaments, for $2.9 billion in cash, from its shareholders, including private investment firm TPG. The acquisition, subject to review, is expected to close in 1H14.   Aptalis had sales of $688 million in FY2013. Sales of its top three products in the U.S. include Canasa, Carafate, and Zenpep, which accounted for more than 60...