Ex parte Reexamination

The AIA replaced inter partes reexamination with IPR proceedings, however ex parte reexamination still remains an available and popular option for those interested in challenging patents at the Patent Office.

Any person may file a request for ex parte reexamination, and unlike PTAB petitions (for IPR and PGR), these requests may be filed anonymously, without any obligation to identify a real party in interest. The request should be granted if it raises “a substantial new question of patentability.” The proceeding is conducted by highly experienced Patent Office examiners in the Office’s Central Reexamination Unit (not by the PTAB), and is usually completed in about eighteen months. In contrast with litigation and PTAB trials, no estoppel applies.

Notable aspects of ex parte reexamination include:

  • Significantly lower cost compared to both litigation and PTAB proceedings
  • Request may be filed at any time during the patent term
  • Grounds for unpatentability are limited to anticipation and obviousness based on printed prior art
  • Other than filing a request, requestor cannot further participate in the reexamination
  • No estoppel applies
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