Terms and Concepts

Inter Partes Reexamination


Inter partes reexamination can be requested by any party other than the patent owner and its privies, at any time during the period of enforceability of a patent [37 C.F.R. § 1.913].  Inter partes reexamination is only available for patents that issued from an original application filed in the United States on or after November 29, 1999 [37 C.F.R. § 1.913].  Until recently, the meaning of “an original application” was not fully settled. The issue was whether an inter partes reexamination can be filed on a patent from a continuation application having a filing date on or after November 29, 1999, but which claims priority to a filing before November 29, 1999.  

The PTO’s position was that “an original application” includes any application with an actual filing date on or after November 29, 1999, regardless of whether that application claimed priority to an application filed before that date.  The PTO’s interpretation was upheld in district court and was subsequently affirmed by the Federal Circuit in Cooper Techs. Co. v. Dudas [Cooper Techs. Co. v. Dudas, No. 2008-1130, slip op. at 2-7 (Fed. Cir. Aug. 19, 2008)].  The practical effect is that only patents whose actual filing date is on or after November 29, 1999, is eligible for inter partes reexamination, irrespective of whether the patent’s effective filing date is earlier.

As with ex parte reexaminations, a third party requester can petition the PTO Director to review a determination refusing inter partes reexamination.  The director’s decision of the petition is non-appealable [37 C.F.R. § 1.927].

A patent owner is entitled to appeal to the BPAI and to the Federal Circuit with respect to any decision adverse to the patentability of any original or proposed amended or new claim of the patent [35 U.S.C. § 315(a)]. A third party requester is entitled to appeal to the BPAI and to the Federal Circuit with respect to any final decision favorable to the patentability of any original or proposed amended or new claim of the patent [35 U.S.C. § 315(b)].

Appeals of Inter Partes Reexamination to BPAI and Federal Circuit

Not a single inter partes reexamination appeal from the BPAI to the Federal Circuit has been decided to date.  The first inter partes reexaminations appealed to the Federal Circuit were voluntarily dismissed by the appellant prior to briefing and oral argument [Cooper Cameron v. SAFOCO Inc., Reexamination Nos. 95/000,015 and 95/000,017, Nos. 2009-1435,-1459 (Federal Circuit)]. While a small percentage of inter partes reexamination certificates have issued from the CRU, a search of BPAI decisions from July 1, 1997 to July 1, 2010 reveals that the BPAI has decided only 29 inter partes reexamination appeals to date [FOIA Reading Room and Database of Final Decisions Issued by the Board of Patent Appeals and Interferences (Last Accessed July 1, 2010)]. A reexamination certificate is issued at the completion of reexamination canceling any claim of the patent finally determined to be unpatentable, confirming any claim determined to be patentable, and incorporating any amended or new claim determined to be patentable. Significantly, seven of these decisions resulted in a non-final, non-appealable decision, and were therefore remanded to the examiner for further prosecution [See Reexamination Control Nos. 95/000,006 (USPN 6,357,595); 95/000,009 (USPN 6,399, 670); 95/000,030 (USPN 6,508,393); 95/000,038 (USPN 6,527,941); 95/000,064 (USPN 6,767,487); 95/000,066 (USPN 6,789,673); and 95/000,069 (USPN 6,789,673)].

One reason for the BPAI’s inability to issue final decisions seems to be a lack of clarity in both the rules and statutes for the role of the BPAI in reviewing CRU decisions.  More specifically, it is not clear whether the BPAI should act as a judge between patent owner and the third party requester, or whether it should sit as a “super examiner,” the role it often takes in appeals.

It has been posed to the authors that the reason no inter partes case make it from the BPAI to the Federal Circuit is due (1) to the very small number of inter partes reexaminations filed in the early years of the statute; and (2) to the practical reality that the inter partes reexamination process is a “work in progress” and like all such endeavors, it takes time to work out the kinks and “get it right.”  Both of these observations appear correct but belie the practical consequences that the goals of inter partes reexamination of being faster, better and cheaper that the district courts in assessing patentability based on patents and printed publications have failed so far in practice.

The Chart entitled “Procedure Following Board Decision for Reexaminations Commenced On or After November 2, 2002” in MPEP § 2601.01 graphically shows at least one remand problem that currently exists.  In this example, the remand from the BPAI to the CRU occurs where a proposed ground of rejection in the reexamination request is not adopted by the CRU examiners in the first Office action.  On appeal to the BPAI, the third party requester raises this as a “new ground of rejection” that should have been made by CRU.  The BPAI agrees but does not have the factual and argument record to decide the rejection and thus remands the reexamination back to the CRU to address with the parties.  This remand may occur for other reasons or may occur a second time.  It is the specter of multiple remands that has created the concern that inter partes reexamination may be fundamentally flawed.

At Sedona PL 2008, this possibility of multiple remands (dubbed the “infinite do loop” from computer programming parlance) was raised and seriously discussed.  Senior PTO officials and others were concerned about its existence.  Since then the authors have conferred with these senior officials and others to assess whether this problem is global or whether it is limited to two possible remands or to certain situations (e.g., the unadopted proposed ground of rejection example discussed).  It seems that it is too early in the deployment of the current inter partes reexamination process to know whether the problem is global.  Moreover, it may be that the BPAI will go more in the direction of acting as a judge who makes a final decision and sets the case for appeal to Federal Circuit, and less as a “super examiner” who remands for another round of prosecution in its review of inter partes reexaminations.

Another possible reason for the lack of cases making it to the Federal Circuit, is that, for a certain small subset of inter partes reexaminations, the process is effective without the need to appeal to either the BPAI or the Federal Circuit.  According to recent PTO statistics, 167 inter partes reexamination certificates have issued out of the 923 total requests filed as of June 30, 2010 [USPTO Inter Partes Reexamination Filing Data (June 30, 2010)].  While this represents only 18% of total inter partes reexaminations, the outcome data indicates that third party requesters succeeded in having all claims cancelled or disclaimed in 49% (82) of the completed inter partes proceedings in which a reexamination certificate issued.  In 43% (71), claims were changed in some way and in only 8% (14) did all claims survive reexamination unamended (Id.). The high success rate is skewed by the significant non-response rate by the patent owner either after a first Office action or after actions later in prosecution.  Because a large number of inter partes reexaminations are also involved in co-pending litigation, this data might simply reflect the cases in which the parties have settled or in which the district court has reached a determination regarding validity.

The practical effect of this uncertainty appears to be that the BPAI remands at least some reexaminations, especially inter partes, back to the CRU. The question has been raised by several people as to why this multiple remand (“infinite do loop”) problem does not exist with ex parte reexamination.  One answer may be the structural difference of the third party requester not having standing once the ex parte request is instituted.  A patent owner has no incentive to raise the “new ground of rejection” argument at the BPAI that the CRU should have adopted a proposed ground of rejection not used from the reexamination request. Based on the authors’ interviews with senior BPAI and CRU personnel, we know the PTO is aware of this issue and is working to assess the issue and perhaps to devise changes that take into consideration the policy goals behind inter partes reexamination.  Specifically, the PTO is seeking an approach that recognizes that inter partes reexamination should not be used as a tool to harass patent owners, but rather should function as a post-grant validity check on issued patents that is faster, cheaper, and better than federal court challenges.  Those objectives formed Congress’s basis for creating the inter partes reexamination process.

Estoppels in inter partes reexamination

Estoppels in an inter partes reexamination flow two ways—from the inter partes reexamination to the civil action and from the civil action to the inter partes reexamination.  In a subsequent civil action, a party cannot argue invalidity of a claim finally determined to be valid or patentable on any ground which that party raised or could have raised during the inter partes reexamination [35 U.S.C. § 315(c)].  The third party is not, however, precluded from asserting invalidity based on newly discovered art that was unavailable to the third party requester and the PTO at the time of the inter partes reexamination [35 U.S.C. § 315(c)].  Similarly, once a final decision has been entered against a party in a civil action that the party has not sustained its burden of proving the invalidity of any patent claim in suit, the party and its privies cannot request inter partes reexamination on the basis of issues that the third party raised or could have raised in the civil action [35 U.S.C. § 317(b)].  It appears from the statute that these estoppels in inter partes cases apply only to civil actions brought in the district court under 28 U.S.C. § 1338 and not to Section 337 ITC investigations.  Whether this was an oversight is unknown, but the authors are not aware of any cases for which estoppel has been applied in an ITC investigation.

Once a request for inter partes reexamination has been granted, the third party requester cannot file a subsequent request for inter partes reexamination while the prior inter partes reexamination is pending [35 U.S.C. § 317(a)].  Further, once a final decision is granted favorable to patentability of any original, proposed amended, or new claim, the third party requester cannot thereafter request inter partes reexamination of such claim on the basis of issues that the third party raised or could have raised in the prior inter partes reexamination [35 U.S.C. § 317(b)].

Finally, after an inter partes reexamination has been instituted, the third party requester is precluded from citing any additional prior art unless it rebuts a finding of the examiner or a response by the patent owner, or if it became known or available after filing the request [37 C.F.R. § 1.948].  There are no estoppels, however, that prevent the third party requester from filing subsequent ex parte reexaminations. But the CRU closely examines such subsequent requests with a close eye to whether there is, in fact, a true SNQ.


[1.4.11 Inter Partes Reexamination] > Cooper Techs. Co. v. Dudas, No. 2008-1130, slip op. at 2-7 (Fed. Cir. Aug. 19, 2008)