 GTCR, a leading private equity firm, announced today that its TerSera Therapeutics LLC TerSera portfolio company has entered into a definitive agreement to acquire the product Xermelo telotristat ethyl from Lexicon Pharmaceuticals, Inc. Lexicon; NASDAQ:LXRX for an upfront purchase price of approximately 159 million plus potential milestone payments based on development and commercialization of Xermelo in a new indication. 