A federal appeals court majority reaffirmed recently that there is a written description requirement for patent inventors under the U.S. Patent Act when the judges held that Eli Lilly & Co. did not infringe Ariad’s patent by making osteoporosis drug Evista® and septic shock treatment Xigris. The federal circuit’s en banc hearing revisited the written description requirement, which was what led to the invalidation of Ariad’s patent. The ruling suggested that the Federal Circuit took on the case in order to reaffirm the existence of a written description doctrine in Section 112 of the Patent Act. Ariad had argued that enablement and written description should be viewed as one requirement, while Lilly argued that precedent supported a separate written description rule to comply with Section 112. Lilly is represented by Finnegan.