Proceedings guide

Inter Partes Review (IPR)

Updated By Wysebridge

Inter partes review is a trial before the Patent Trial and Appeal Board in which anyone other than the patent owner asks the USPTO to cancel claims of an issued patent as anticipated or obvious, using only prior patents and printed publications. A petition can generally be filed nine months after grant, and no later than one year after the petitioner is served with an infringement complaint.

Key Facts

Statute
35 U.S.C. §§ 311–319
Who can file
Anyone except the patent owner
Opens
9 months after grant, or after any PGR ends
Deadline if sued
1 year after service of the complaint
Grounds
§§ 102 and 103, on patents and printed publications
Institution standard
Reasonable likelihood of prevailing on at least one claim
Final decision
Within 1 year of institution (extendable 6 months)
Estoppel
Yes, § 315(e)
On this page
  1. The IPR timeline
  2. Who may file, and when
  3. What you can argue
  4. Standards that matter
  5. Amendments
  6. Estoppel
  7. Settlement and appeal
  8. IPR compared with other options

The IPR timeline

  1. Day 0Petition filedClaims challenged, grounds, evidence and every real party in interest.
  2. A few weeksNotice of filing dateThe Board confirms the petition is complete.
  3. Up to 3 monthsPatent owner preliminary responseOptional; argues trial should not begin.
  4. Up to 3 more monthsInstitution decisionTrial starts only if the petition shows a reasonable likelihood of prevailing.
  5. About 12 monthsTrialPatent owner response, any motion to amend, petitioner reply, depositions and oral hearing.
  6. Within 1 year of institutionFinal written decisionPatentability of each challenged claim; appealable to the Federal Circuit.

Inter partes review (IPR) was created by the America Invents Act and began on September 16, 2012. It is the main route for challenging a patent’s validity at the USPTO after the first nine months.

Who may file, and when

  • Who: any person who is not the patent owner (35 U.S.C. § 311(a)). No standing requirement applies at the USPTO, although appeal rights are narrower for parties who lack Article III standing.
  • Earliest filing: after the later of nine months from grant, or the end of any post-grant review of the patent (§ 311(c)).
  • Latest filing if you were sued: within one year of being served with an infringement complaint (§ 315(b)). Missing this date bars institution.
  • Declaratory-judgment bar: a petition is barred if the petitioner first filed a civil action challenging the patent’s validity (§ 315(a)).

What you can argue

Only anticipation and obviousness (35 U.S.C. §§ 102 and 103), and only on the basis of patents and printed publications (§ 311(b)). Arguments such as lack of written description, indefiniteness, or patent-ineligible subject matter cannot be the basis of an IPR ground. For those, see post-grant review or district court.

Standards that matter

  • Burden of proof: the petitioner must prove unpatentability by a preponderance of the evidence (§ 316(e)).
  • Claim construction: for petitions filed on or after November 13, 2018, the Board applies the same standard used in federal courts (Phillips), not the older “broadest reasonable interpretation.”
  • Discretionary denial: the Office may decline to institute even when the statutory test is met, for example because of parallel litigation or serial petitions. These practices have been revised more than once in recent years, so check current USPTO guidance before filing.

Amendments

A patent owner may move to amend by canceling claims or proposing a reasonable number of substitute claims. Amendments cannot add new matter or enlarge the scope of the claims (§ 316(d)).

Estoppel

After a final written decision, the petitioner, its real party in interest, and its privies cannot assert in the USPTO, a district court, or the ITC that a challenged claim is invalid on any ground the petitioner raised or reasonably could have raised in the IPR (§ 315(e)). Who counts as a real party in interest or privy therefore matters a great deal.

Settlement and appeal

An IPR can end by joint request before a final written decision (§ 317). Final written decisions are appealable to the Federal Circuit (§ 319). The decision to institute is generally not reviewable on appeal (§ 314(d)).

IPR compared with other options

IPR is adversarial and fast, but carries estoppel. Ex parte reexamination has no estoppel but little requester participation. Post-grant review is the earlier, broader window. See the comparison chart.

Frequently Asked Questions

Who can file an IPR petition?

Any person other than the patent owner may file, subject to the statutory bars in 35 U.S.C. § 315. The petitioner does not need to have been sued.

What is the IPR time bar?

A petition may not be instituted if it is filed more than one year after the petitioner, its real party in interest, or a privy was served with a complaint alleging infringement of the patent (35 U.S.C. § 315(b)).

Can I raise invalidity under section 101 or 112 in an IPR?

No. IPR grounds are limited to anticipation (section 102) and obviousness (section 103), and only on the basis of patents and printed publications. Post-grant review allows broader grounds.

Can an IPR decision be appealed?

A party dissatisfied with the final written decision may appeal to the U.S. Court of Appeals for the Federal Circuit. The decision whether to institute is generally not appealable.

Primary Sources

  1. 35 U.S.C. §§ 311–319 (Inter partes review)
  2. 37 C.F.R. Part 42, Subparts A and B
  3. USPTO Patent Trial and Appeal Board

Educational information; not legal advice. Statutes, rules and USPTO practice change. Confirm against the primary sources and consult a registered patent practitioner before acting. Disclaimer.