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Inter Partes Review

By Eugene T. Perez

Inter partes review (“IPR”) has replaced inter partes reexamination on September 16, 2012.  Also, effective on September 16, 2011, the threshold standard for granting inter partes reexamination changed from a “substantial new question of patentability” (“SNQ”) to “reasonable likelihood that the petitioner will prevail” with respect to at least 1 of the patent claims. This same threshold standard of “reasonable likelihood that the petitioner will prevail” is used in IPR.

In summary, a third party (not the patent owner) will be able to request an IPR of an issued patent after 9 months following issuance (but later of a patent issuance or termination of any post-grant review (“PGR”)).  Unlike PGR where any ground of rejection can be a basis, only prior art can be used to institute IPR.  Like PGR, the third party requester must identify all real parties in interest.  Also like PGR, an IPR cannot be instituted if there is a prior civil suit challenging validity of the same patent.  But if an IPR is instituted, a later or same day filed civil suit would be automatically stayed (with exceptions as identified in § 315).  Further, in contrast to inter partes reexamination, any patent is subject to IPR.  Finally, like PGR, estoppel for IPR applies with issuance of the United States Patent & Trademark Office (“USPTO”) Patent Trial and Appeal Board (“PTAB”) decision, wherein the third party requester or its privies cannot participate in any USPTO proceeding or file any court action against the patent which asserts that a claim in the patent is invalid “on any ground that the petitioner raised or reasonably could have raised” during the initial IPR.

I.       Time Frame

The third party/petitioner can request an IPR of an issued patent after 9 months following issuance, but the later of patent issuance or termination of any PGR.  As amended, 35 U.S.C. § 315(b) provides that an IPR may not be instituted if the petition requesting the proceeding is filed more than one year after the date on which the petitioner, real party-in-interest, or privy of the petitioner is served with a complaint alleging infringement of the patent. However, this time limitation does not apply to a request for joinder under 35 U.S.C. § 315(c).

II.      The Petitioner

A petitioner in an IPR may request to cancel as unpatentable one or more claims of a patent only on a ground that could be raised under 35 U.S.C. §§ 102 or 103 and only on the basis of prior art consisting of patents or printed publications (not, e.g., on-sale bar).  A petition filed under 35 U.S.C. § 311, as amended, may be considered by the Office only if certain conditions are met:

  1. Payment of the $9,000.00 request fee, and $200 for claim in excess of 20 claims being requested (an additional $14,000 fee is required for instituting IPR, and $400 for each claim in excess of 15 claims being reviewed);21
  2. the petition must identify all real parties in interest;
  3. the petition must identify, in writing and with particularity, each claim challenged, the grounds on which the challenge to each claim is based, and the evidence that supports the grounds for the challenge to each claim, including
    • Copies of patents and printed publications that the petitioner relies upon in support of the petition;
    • affidavits or declarations of supporting evidence and opinions, if the petitioner relies on expert opinions
  4. the petition must provide such other information required by regulation; and
  5. the petitioner must provide copies of any of the documents required under paragraphs (2), (3), and (4) of 35 U.S.C. § 312(a) to the patent owner or, if applicable, the designated representative of the patent owner.

III.    Starting the IPR Proceeding

If an IPR petition is timely filed, the patent owner has the right to file a preliminary response (within 3 months of the petition) to the petition that sets forth reasons why no IPR should be instituted based upon the failure of the petition to meet any of the requirements listed above. The petitioner has the burden of proving a proposition of unpatentability by a preponderance of the evidence.


The USPTO will determine whether to institute an IPR within three months after: (1) Receiving a preliminary response to the petition; or (2) if no such preliminary response is filed, the last date on which such response may be filed. The USPTO will notify the petitioner and patent owner, in writing, of the Office’s determination of whether to institute IPR, and will make the notice available to the public as soon as is practicable.  The notice will include the date on which the review will commence. The Office may not authorize an IPR to be instituted unless the information presented in the petition and any response filed by the patent owner shows that there is a reasonable likelihood that the petitioner would prevail with respect to at least one of the claims challenged in the petition.  It is currently understood that the “reasonable likelihood” standard means satisfying a prima facie case of unpatentability.

IV.    During the IPR Proceeding

During an IPR, the patent owner may file one motion to amend the patent in one or more of the following ways: (A) cancel any challenged patent claim; and (B) for each challenged claim, propose a reasonable number of substitute claims.3 Also, 35 U.S.C. § 316(d)(2) provides that additional motions to amend may be permitted upon the joint request of the petitioner and the patent owner to advance materially the settlement of a proceeding.  The patent owner is not allowed to enlarge the scope of the claims of the patent or introduce new matter.

V.      Stays and Merger

35 U.S.C. § 315(a)(1) provides that an IPR may not be instituted if, before the date on which the petition for review is filed, the petitioner or real party-in-interest had filed a civil action challenging the validity of a claim of the patent.  There is automatic stay of a civil action brought by the petitioner or real party-in-interest challenging the validity of a claim of the patent and filed on or after the date on which the petition for IPR was filed, until certain specified conditions are met. Also, a counterclaim challenging the validity of a claim of a patent does not constitute a civil action challenging the validity of a claim of a patent.

Also, 35 U.S.C. § 315(d) provides that, during the pendency of an IPR, if another proceeding or matter involving the patent is before the Office, the Director may determine the manner in which the inter partes review or other proceeding or matter may proceed, including providing for stay, transfer, consolidation, or termination of any such matter or proceeding.

VI.    Estoppel

A final written decision by the USPTO PTAB, resulting from an IPR proceeding, estops (precludes) the petitioner, or the RPI of the petitioner or any privy of the petitioner, from asserting in a district court proceeding, an International Trade Commission (“ITC”) proceeding, or any other USPTO proceeding (e.g., an ex parte reexamination) that a claim is invalid or unpatentable on any ground the petitioner “raised or reasonably could have raised” during the IPR proceeding.

As a basic example of estoppel, if Company X raises the issue that Company Z’s patent is unpatentable for obviousness due to Reference A in combination with Reference B in the IPR, and Company X loses the IPR, Company X cannot later raise another issue, such as a rejection for Reference A in combination with Reference C (where C was known at the time of the initial IPR request), in any proceeding if that issue could have been raised in the IPR.   Therefore, if you do get involved in an IPR, you do not get “two bites at the apple” in any forum.

VII.     Settlement

The IPR can be terminated with respect to any petitioner upon the joint request of the petitioner and the patent owner, unless the USPTO has decided the merits of the proceeding before the request for termination is filed.  35 U.S.C. § 317(a) also provides that if the IPR is terminated with respect to a petitioner, no estoppel will attach to the petitioner, or to the real party-in-interest or privy of the petitioner, on the basis of that petitioner’s institution of that IPR. Any such agreement will be treated as business confidential information, will be kept separate from the file of the involved patents, and will be made available only to Federal Government agencies on written request, or to any person on a showing of good cause.


  1. 35 U.S.C. § 314(a) (as amended).
  2. 37 C.F.R. § 42.15(a).
  3. 35 U.S.C. § 316(d)(1).