Inter Partes Review
IPR has been the most frequently used PTAB proceeding. Any person other than the patent owner may file an IPR petition to challenge validity based on printed publication prior art that may or may not have been considered by the patent examiner. Although available to non-litigants, IPRs are primarily used as a way for accused infringers to challenge patent validity, and as a basis to request a stay of related litigation.
If litigation has begun, the defendant must file its IPR petition within one year after the complaint has been served. Non-litigants are not restricted by this time limit. For PGR-eligible patents (based on applications filed on or after March 16, 2013), an IPR cannot be initiated during the time period that a PGR is available or during the pendency of a PGR.
The PTAB will institute an IPR only on grounds of anticipation or obviousness based on printed prior art, if the petition demonstrates that there is “a reasonable likelihood” that at least one challenged claim is unpatentable.