« In the USA, inter partes review (IPR) is one of a number of mechanisms for eliminating improper patents through post-grant review introduced with by the AIA. While the purpose of IPRs is to provide a cheaper and more expert based alternative to litigation for screening out bad patents, the devil is in the design details. For example, the inclusion of key procedural features in IPRs, such as fixed time frames and expanded discovery contributed to making it far more popular than its predecessors. However, it is also very much criticized and the comparison of IPR with other post grant review systems, such as the opposition in Europe and litigation in Germany, shows how small differences can have a large impact. At the moment when France intends to introduce in its legislation an opposition mécanisme, the experience in other juridictions can be bring a beneficial hindsight». 

Alfred Spigarelli wrote with professors Chien and Helmers an article onto ” « The Inter Partes Review and the Design of Post-Grant Patent Reviews »“, published in the Berkeley Technology Law Journal, Vol. 33, No. 817, 2019.