In recent years, there has been widespread litigation related to intellectual property disputes and alleged antitrust violations surrounding generic entry across a wide range of therapeutic classes. For example, over 90 percent of the drugs experiencing initial generic entry between 2011 and 2014 had one or more patent challenges associated with a generic application¹. Furthermore, settlements in these cases have triggered numerous reverse-payment lawsuits. These cases frequently involve economic questions related to, among other things, class certification, market definition and damages. As biosimilars are now becoming available in the U.S., the question is whether a similar experience awaits with respect to the nature and extent of likely litigation. The answer is not that simple given the economics of biosimilars as well as some key differences between large-molecule (biologic) drugs and small-molecule (chemical) drugs.