Terms and Concepts

Duty of Disclosure

It is clear that the patent owner remains under a duty of disclosure while the patent is in reexamination proceedings under 37 C.F.R. §§ 1.555 and 1.933.  Further, a third party requestor participating in an inter partes reexamination owes a duty of candor and good faith to the PTO under 37 C.F.R. § 11.18.  The ongoing duty of disclosure for the patent owner raises some interesting strategic questions considered below.

For instance, who should handle the reexamination?  Options include using patent attorneys from the trial team, or prosecution attorneys from the litigating law firm.  Alternatively, outside patent attorneys or patent attorneys inside the patent owner’s company could be used.  Critical issues to consider include efficiencies, maintenance of privilege, and perhaps most importantly, compliance with protective orders.  Best practices may warrant use of outside patent attorneys for the prosecution of the reexamination who are walled off from the litigation team, especially where the protective order includes a non-prosecution clause.

Another strategic question is determining what to cite to the CRU.  The MPEP requires citation of “patents or printed publications which (A) are material to patentability in a reexamination proceeding, and (B) which have not previously been made of record in the patent file” [MPEP § 2280].  Validity decisions in reexamination may not be made on the basis of fraud on the Office, or on the basis of prior use or sale.  Therefore, the patent owner arguably has fewer categories of potentially relevant material to cite to the PTO.  However, it appears as if the obligation remains to disclose the same broad scope of prior art printed publications as would be the case in the original prosecution [MPEP § 2280 and 2684].

However, because the prevalence of inequitable conduct charges in patent litigation remains unabated (See Serdarevic v. Advanced Med. Optics, Inc., 87 U.S.P.Q.2d 1481, 1484-85 (Fed. Cir. 2008) (holding that the presumption of laches applied against inventorship claim despite intervening reexamination proceeding)), many reexamination practitioners reasonably err on the side of caution in preparing information disclosure statements.  For instance, in the recent case of Larson Mgf. Co. v. Aluminart Prods. LTD., the district court found a reexamined patent to be unenforceable for failure to cite information from a related co-pending application.  Specifically, the patent owner failed to cite a number of references applied in the co-pending application, as well as two Office actions where the application examiner had considered the same art as the CRU examiner.  The Federal Circuit overturned the inequitable conduct charge finding that the uncited references were cumulative.  But in doing so, the Court also determined that the office actions were material.  The case was remanded to consider whether the requisite intent was present as to the uncited Office actions.  There was no mention by the Court of the fact that the MPEP does not appear to require citation of material “previously…made of record in the patent file.”

Arguably the patent owner is required in the reexamination to disclose the same broad scope of prior art as would be the case in the original prosecution.  The result of cases such as Larson Mfg. is that the filing of a voluminous IDS  citing all types of prior art uncovered in the course of a concurrent patent litigation are regularly filed in reexamination proceedings — filings that include re-citation of all the art previously filed in any parent or otherwise-related applications during regular prosecution.  Where a patent owner feels compelled to cite material that may not be strictly required by the MPEP, it may simplify matters for the CRU.  There are many examples of IDS filings in reexaminations where hundreds of possible prior art items disclosed during a concurrent litigation are dumped on the CRU by using separate IDS pleadings for different categories of information.  For instance, one pleading may clearly cite to art previously cited during original prosecution of related applications, while a second pleading may cite to art newly discovery during the concurrent litigation or ITC investigation.  The CRU examiner can then more easily discern what she may consider relevant to a particular case.

Yet another strategic question revolves around what information to cite from a co-pending district court litigation or ITC investigation.  The MPEP states that the duty of disclosure under Rule 555 “is consistent with the duty placed on patent applicants” by Rule 56.  In that regard, Rule 56 requires citation of “[i]nformation from related litigation” [MPEP § 2001.06(c)].  Such information includes “pleadings, admissions, discovery including interrogatories, depositions, and other documents and testimony.”  Such categories of information may include assertions that are contradictory to assertions made to the examiner.  Where there are concurrent litigation or ITC investigation proceedings, these classes of information must be continually monitored and cited to the office where relevant.  Again, because of the prevalence of inequitable conduct charges, many practitioners err on the side of caution and are reasonably over-inclusive in this regard.  If information is cited that is beyond the scope of the reexamination proceedings–e.g., information related to allegations of prior sale or use–the CRU will simply note the issue as unresolved [MPEP § 2280].

The reexamination proceeding is strictly limited to considering prior art in the categories of patents, printed publications and admissions, and cannot address other forms of prior art such as public use, offer for sale, public knowledge, etc.  Considerable CRU resources are wasted by examiners considering art that cannot form the basis of a rejection of the original issued claims in a reexamination (if a patent owner chooses to add new claims or amend claims during a reexamination proceeding, the added language is subjected to a broader examination, similar to that of an examination of an original application).  For example, the new claim or new limitation is considered for compliance under 35 U.S.C. §112 (See MPEP §2258.II).  Furthermore, some practitioners argue that non-patent, non-publication prior art (e.g., prior use, prior offer for sale) is material to new claims and/or new limitations added during reexaminations. However, only submitting patents and printed publications in an IDS does not relieve the patent owner and its reexamination attorneys of the risk of violation of the duty of disclosure and possibly committing inequitable conduct.

Further 37 C.F.R. § 11.18 requires the patent owner’s reexamination attorneys to conduct a reasonable inquiry of submissions to the PTO, which means that some level of review of each prior art submission should be done prior to filing.  Currently it seems that due to the risk of inequitable conduct, patent owners are erring of the side of voluminous IDS filings and are not culling out possible prior art that does not fit into the categories of patents, printed publications and admissions.

Throughout the inter partes reexamination proceeding, the patent owner also has an obligation to “call the attention of the Office to any prior or concurrent proceedings in which the patent is or was involved, including but not limited to interferences, reissue, reexamination, or litigation and the results of such proceedings” [37 C.F.R. § 1.985; see also § 1.565 for similar ex parte rule].  Additionally, any party may file a paper in an inter partes reexamination proceeding notifying the Office of the same.  How much information is a party required to submit from a concurrent litigation?  Is bare notice of a concurrent proceeding sufficient to meet the obligation imposed by Rule 985?  Many patent owners are submitting voluminous court documents from concurrent litigation.  Many of these documents would not qualify as prior art during original prosecution or reexamination prosecution.

One unresolved issue in this regard is the extent to which the duty of disclosure under Rules 555 and 933 would apply to a patent owner’s trial team. What if the trial team is completely barred by the protective order from participating in the prosecution of a concurrent reexamination? How high and impervious must the wall be between the trial team and the reexamination team to avoid implicating the duty of disclosure rules?  What if one or more members of the trial team are registered patent attorneys? What disclosure obligations does a patent owner have, and can these obligations be avoided by remaining intentionally ignorant of prior art or other potentially relevant information that is confidentially disclosed over the course of the litigation?

These are very important questions as the trial team is likely to become aware of material prior art or other material information either through its own investigation or simply through the accused infringer’s disclosure of its invalidity contentions.  At least one recent district court decision suggests that the duty of disclosure does NOT trump a trial attorney’s obligations under the protective order to maintain the confidentiality of protected information [2.1.03 Protective Orders].  As a final matter, while possibly not under the same duty of disclosure as a patent owner, the requester nonetheless has the duty of candor during the PTO proceeding, as that Rule 11.18 applies equally to both reexaminations and all other proceedings before the PTO [37 C.F.R. § 11.18].

The uncertainty between the required and also preferable bounds of the duty of disclosure in reexaminations and the ever present specter of a violation of the duty of disclosure, where even many at the PTO will say they do not know where the real lines are, is argued by some as just another example of why significant change in the law of inequitable conduct (or the duty of disclosure) needs to occur, whether by court decision or legislative change.

Privilege Issues

Is there a waiver of privilege when a PTO submission, prosecution event, or meeting uses litigation work product or reveals trial strategy?  The patent owner has an obligation to inform the PTO of any concurrent district court litigation in ex parte and inter partes reexaminations.  While the CRU monitors the concurrent litigation, it is prudent for the patent owner to view this as an ongoing duty.  For inter partes reexamination, any person can file a paper notifying the PTO of a concurrent proceeding.

If a party thinks information must be disclosed, the protective order should specify procedure for the parties to “meet and confer” to resolve any disclosure issues.  If parties cannot agree, then the issue may need to be raised to the presiding judge.  One way to protect information that a party feels must be disclosed, but is designated under the protective order, is to file the information under seal at the PTO with a petition to expunge at the conclusion of the proceeding [MPEP §§ 724.04 - 724.06]. 

The PTO specifies detailed procedures for filing information under seal in pending applications.  The information to be protected is submitted in a labeled, sealed envelope.  A petition to expunge the information accompanies the sealed documents.  If the examiner does not believe the sealed information is material to patentability, the petition is granted and the information is expunged from the file.  If the information is deemed material to patentability, the petition is denied, the information will become part of the application record, and the information will be available to the public.

It is important to note, however, that the information filed under seal may be made public at the conclusion of the reexamination process, if the information is deemed material to patentability.  Therefore, the court and the party owning the confidential information should be involved in the decision to disclose and how the disclosure is made to the PTO.


  • Interrogatory and Production Requests
  • Disclosing Art Discovered During Litigation
  • The Specter of Inequitable Conduct
  • Rule 985 – Notice of Concurrent Proceedings
  • Duty of Disclosure and the Owner’s Trial Team
  • Rule 11.18 – The Requester’s Duty of Candor