A Comparison of US and EPO Post Grant Practices
Challenging the validity of a patent through the courts of Europe and the United States can be a time-consuming and expensive process. Oppositions at the European Patent Office (EPO) and US post-grant cancellation proceedings—namely, post-grant review (PGR) and inter partes review (IPR)— adjudicated by the Patent Trial and Appeal Board (PTAB) – can be effective tools for dealing with competitors' patents. Because many inventions are protected by closely related patents in both Europe and the US, companies often face the prospect of having their patents challenged in both jurisdictions. Therefore, understanding the similarities and differences between these proceedings is essential for companies with IP interests in both jurisdictions.
PGRs, IPRs, and oppositions overlap in significant respects. All three of these proceedings are contentious, administrative procedures intended to allow a third party to challenge the claims of a granted patent. Lack of novelty and inventive step (obviousness in the US) over prior printed publications can be grounds for challenging patents in all three of these proceedings. All three proceedings also require identification of the challenged claims, the grounds upon which the claims are challenged, and relevant evidence supporting these grounds. In addition, all three proceedings have similar timelines from the filing of a petition to reaching a final decision—about 18 months in an IPR/PGR, and about 15-24 months in an opposition (although the PTAB follows this timeline much more closely than the opposition division). Finally, in all three proceedings parties retain ability to settle the case, albeit this ability is not indefinite.
The similarities between IPRs and oppositions end here, while PGRs have more in common with their European counterparts. For example, both PGRs and oppositions must be filed within nine months from patent grant, whereas IPRs can be filed at any time after grant. Also, in addition to the lack of novelty and obviousness attacks allowed in IPRs, grounds based on lack of written description and enablement are available in PGRs and oppositions. Further, a patent owner has a right to amend claims in both jurisdictions, although this is very rarely granted in the US.
Another key difference in the proceedings is the threshold that a challenger must clear to commence a proceeding. The PTAB applies a much more rigorous standard when deciding whether to institute a PGR/IPR than the standard used by the EPO. In addition, if the PTAB refuses to institute a proceeding, a challenger is unable to appeal the decision. Thus, at least theoretically, the chances of defending a meritless patent challenge are much higher in Europe than in the United States. Also, a limited amount of discovery is allowed in PGRs/IPRs, but not in oppositions. For example, both parties can question any expert that provides testimony, through the use of expert declarations, in either PGRs or IPRs. But the EPO will consider expert and witness testimonies only when they are highly relevant, and will focus primarily on the prior art references that are offered in support of the parties’ arguments. Further, the effect the administrative proceedings have on later litigation is different in the US and Europe. A challenger in a European opposition is never in danger of forfeiting arguments in any future patent invalidity proceedings. Indeed, the same party that lost an opposition is free to challenge the same claims in national courts on grounds that were considered in the lost opposition, or on related grounds. But in the US, once the PTAB issues a final written decision, the challenger is barred from raising any issue that was raised or could have been raised during the review proceedings at either the USPTO, district court, or United States International Trade Commission (USITC).
As discussed in the companion article, “EP Opposition and US Inter Partes Review Decisions Go Hand In Hand,” despite their differences, US and European proceedings are often decided in a similar manner.
 To date, few federal cases have ruled on the scope and effect of estoppel, although the emerging body of law points to a much more relaxed interpretation of the estoppel provision that what was originally anticipated.