A few years after divesting businesses, two biopharmaceutical companies are buying them back. Conatus Pharmaceuticals has acquired Pfizer’s Idun Pharmaceuticals subsidiary for an undisclosed amount. San Diego-based Conatus was founded in July 2005 by former Idun managers after they sold Idun to Pfizer. At the time, Idun had a liver disease drug candidate in Phase II clinical trials and preclinical oncology candidates. Conatus’ own lead candidate is in Phase II trials for treating hepatitis C. Meanwhile, Texas-based Lexicon Pharmaceuticals has opted to purchase Symphony Icon and thus reacquire a portfolio of serotonin synthesis inhibitor programs targeting gastrointestinal diseases. In 2007, in exchange for Lexicon stock, Symphony Capital Partners put up $60 million, of which $45 million went to set up Symphony Icon. The buyback deal allows Lexicon to defer paying a sizable part of the repurchase price and make a significant portion of the payment contingent on the success of the drug programs. Lexicon will pay the investors $10 million up front and possibly $80 million more in future cash and stock.