Shire Plc has agreed to buy U.S. group NPS Pharmaceuticals Inc. for $5.2 billion in cash, expanding its portfolio of medicines for rare diseases. Shire gains two new drugs, Gattex, a treatment for short-bowel syndrome (SBS), and Natpara, which is awaiting approval from the FDA for hypoparathyroidism. According to Thomson Reuters Cortellis, the two NPS medicines may achieve annual sales of $509 million and $534 million, respectively, by 2019.   SBS is a potentially fatal gastrointestinal disorder...