GlaxoSmithKline has made several changes to its corporate executive management team. The appointments will take effect on May 22 when Andrew Witty officially assumes the role of chief executive officer.     Mr. Witty remarked, “It is clear that our industry is facing a rapidly changing environment. Demand for innovative medicines and healthcare products continues to grow, however we are also presented with increasing challenges, such as cost containment, regulatory pressures and generic...