Novartis kicked off a new era in U.S. medicine on Thursday with the launch of the first "biosimilar" copy of a biotechnology drug approved in the United States, at a discount of 15 percent to the original. The Swiss drugmaker's generics unit Sandoz said Zarxio, its form of Amgen's white blood cell-boosting product Neupogen, would increase access to an important treatment by offering a "high-quality, more affordable version".