Terms and Concepts

Risks for Accused Infringers

The clearest risk for an accused infringer is that at least one asserted patent claim survives the reexamination process unamended and without any adverse prosecution history estoppels.  The reexamination may allow the patent owner to have the CRU consider all of the prior art in the litigation and to present arguments and declarations that support patentability of the claims over this prior art.  This could include, for instance, possible secondary (objective) considerations of non-obviousness that were not present when the claims were originally prosecuted.

An ex parte reexamination may also give the patent owner a significant advantage in dealing with the prior art because, once begun, the third party requester is excluded from the process, while the patent owner can interview the examiner.  Although the court can find a patent invalid even if it survives reexamination, most judges likely will defer to the presumed administrative expertise of the PTO, CRU, and BPAI.

Further, putting an asserted patent into reexamination could allow the patent owner to correct other defects in the patent, such as potentially ambiguous claim language, antecedent basis problems, or other perceived issues with the claims.  This is especially true with newly-issued patents where the potential for damages lies in the future, rather than with past damages.  In the same vein, patent owners can also add claims during reexamination, provided that the added claims are not broader in scope than the original claims in reexamination.  The added claims could strategically cover aspects of the accused infringing products not included in the issued claim set, although prohibitions against broadening amendments may bar such activity.

Finally, a reexamination request filed early on in the litigation could impact trial.  This is especially true where the PTO decisions are favorable to patentability.  However, as noted above, there are questions and concerns as to the admissibility of any non-final PTO action at trial.


  • Correction of Defects
  • Strategic Amendment
  • Favorable to Patentability