Ex Parte Reexamination
Prior to the AIA, reconsideration by the PTO of patentability of an issued patent could be requested by Ex Parte Reexamination or Inter Partes Reexamination. Ex Partes Reexamination remained unchanged by the AIA but Inter Partes Reexamination was replaced by Inter Partes Review and Post Grant Review. Nevertheless, Inter Partes Reexaminations filed prior to September 16, 2012 will be handled under the rules prior to September 16, 2012. No Inter Partes reexaminations may be filed on or after September 16, 2012.
If certain threshold conditions are met, namely a substantial new question of patentability is raised, the PTO will grant a request for an Ex Parte Reexamination. Only the patent owner may participate in the reexamination process. This excludes a patent challenger from the process once it has been initiated. Grant of a request for Inter Partes Reexamination requires that the request establish a reasonable likelihood that the requestor would prevail, with respect to at least one claim. A third party requester may, however, participate in the reexamination process. In either case, the bases for requesting the reexamination must be limited to patents or publications not previously considered when the patent was originally examined. Challenges may not be based on 35 USC §112, for example.
Both Ex Parte and Inter Partes reexamination effectively submit the patent to an examination process, much like that to which original applications are submitted, but with the added consideration of the previously unconsidered prior art. Ex Parte Reexamination may be requested by anyone at any time, but only the patent owner participates in the reexamination proceeding. In Inter Partes reexamination, a third party requester may participate. For a comparison of Ex Parte Reexamination and Inter Partes Reexamination, see Ex Partes vs. Inter Partes Reexamination Comparison.