The Patent Trial and Appeal Board
May 28, 2024
and Inter Partes Review
Christopher T. Zirpoli
The 2011 Leahy-Smith America Invents Act (AIA) is widely viewed as the most significant
Legislative Attorney
patent statute enacted by Congress in over 50 years. Although the AIA made many important

changes to U.S. patent law, the most practically significant was the creation of the Patent Trial
Kevin J. Hickey
and Appeal Board (PTAB).
Legislative Attorney

PTAB is a tribunal within the U.S. Patent and Trademark Office (USPTO), the federal agency
responsible for reviewing patent applications and granting patents. The AIA created PTAB and

granted it authority to hear several new types of administrative challenges to the validity of
patents previously granted by USPTO. These challenges, which were also created by the AIA, include inter partes review
(IPR) and post-grant review (PGR). IPRs and PGRs are typically decided by a panel of three administrative patent judges
(APJs).
Entities accused of patent infringement have always been able to challenge the validity of patents asserted against them in
federal court. Because those patents were reviewed and granted by USPTO, patents carry a presumption of validity when
challenged in court. Patent invalidity must be demonstrated by a higher standard of proof (clear and convincing evidence)
than the standard used for most issues in civil litigation (preponderance of the evidence). Litigating a patent case to a final
judgment in a federal court is time-consuming and expensive: it typically takes several years, with average legal costs
amounting to over a million dollars. In addition, because of judicial standing requirements, an entity can usually ask a court
to decide the validity of a patent only if they have been sued or at least threatened with a patent lawsuit.
Congress’s stated aim when creating IPR and PGR was to improve patent quality by providing a more efficient means to
adjudicate patent validity issues. Congress was also concerned that poor-quality patents fueled litigation by so-called “patent
trolls,” a pejorative term for patent plaintiffs that do not manufacture or sell the patented products. From the perspective of a
person accused of patent infringement (or worried about being sued), PTAB procedures are often more advantageous than
federal court litigation in that they are faster, cheaper, and use a lower standard of proof. By statute, IPRs and PGRs are
supposed to reach a final determination no later than one year after PTAB decides to institute the proceeding. The
administrative procedures are more streamlined than civil litigation, with average legal costs typically in the hundreds of
thousands of dollars (as opposed to millions). In addition, PTAB does not require standing, so any person other than the
patent holder can challenge a patent before PTAB. As a result, it has become common for entities sued for patent
infringement in federal court or before the U.S. International Trade Commission to petition PTAB to institute an IPR and
seek to challenge the patent in that forum.
PTAB procedures—and IPR in particular—have aroused controversy among patent stakeholders since the enactment of the
AIA. Critics of PTAB argue that it is biased against patent holders, creates uncertainty in patent rights, and discourages
investment in innovation. PTAB critics further maintain that IPR is unfair to patent holders, who have successfully obtained a
patent before USPTO but must now again defend their patent’s validity before the same agency.
Since 2011, the Supreme Court has heard a number of cases concerning PTAB. In Oil States Energy Services v. Greene’s
Energy Group, the Supreme Court rejected a constitutional challenge to IPR, holding that challenges to already-issued
patents in an administrative forum did not violate the Seventh Amendment or Article III of the U.S. Constitution. In United
States v. Arthrex Inc., the Court held that the unreviewable authority exercised by APJs violated the Constitution’s
Appointments Clause but spared PTAB by granting the Director of USPTO discretionary authority to review PTAB
decisions.
Members of Congress have examined whether to maintain PTAB as it exists or to modify IPR and PGR procedures, with
both House and Senate committees holding hearings on the issue. Legislative proposals introduced in recent Congresses
include bills that would abolish PTAB entirely or make various procedural and substantive reforms to PTAB. For their part,
USPTO and PTAB have issued regulations, precedential decisions, and other guidance on issues including USPTO Director
review, repeat IPR petitions, and when PTAB should exercise its discretion to decline to institute (i.e., hear) an IPR or PGR.
In 2024, USPTO issued notices of proposed rulemaking (NPRMs) on some of these issues.

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Introduction
The Patent Trial and Appeal Board (PTAB), which is part of the U.S. Patent and Trademark
Office (USPTO), was created by Congress in 2011 through the Leahy-Smith America Invents Act
(AIA).1 The AIA established new administrative procedures to challenge patent validity called
inter partes review (IPR) and post-grant review (PGR).2 While entities accused of patent
infringement have long been able to challenge the validity of the patents asserted against them in
court, IPR and PGR allow a party to petition PTAB to hear a challenge to the validity of an
already-issued patent in an administrative forum, regardless of whether the petitioner has been
sued or threatened with suit for patent infringement.3
IPR and PGR thus provide a way for anyone to challenge patents before USPTO and, if
successful, cancel patent claims that PTAB concludes should have never issued.4 From an
accused patent infringer’s perspective, using IPR or PGR to challenge patent validity is often
more advantageous than judicial proceedings because PTAB processes are typically faster and
less expensive, and require a lower burden of proof to invalidate patents.5 It is thus common for
entities threatened with or sued for patent infringement in court or in the U.S. International Trade
Commission (ITC) to petition PTAB to attempt to invalidate the patents asserted against them in
those other forums.6
Congress’s stated purpose in creating PTAB was to “improv[e] patent quality and provid[e] a
more efficient system for challenging patents that should not have issued; and reduc[e]
unwarranted litigation costs.”7 Congress also observed that poor-quality patents may fuel
litigation by so-called patent “trolls,”8 a pejorative term for patent plaintiffs that do not
manufacture or sell the patented products.9 On this view, PTAB may be seen as an attempt to
reduce patent-troll litigation by weeding out poor-quality patents.
Some stakeholders have criticized PTAB, labeling it a “patent death squad.”10 Critics of PTAB
argue that PTAB has made it too easy to challenge patents, creating uncertainty in patent rights,
stifling innovation, and discouraging investments in patent-intensive industries and early-stage

1 Pub. L. No. 112-29 (2011).
2 A third procedure created by the AIA was transitional and sunsetted in 2020. See infra “Covered Business Method
Review.”
3 See 35 U.S.C. §§ 31–32.
4 See generally CRS Report R46525, Patent Law: A Handbook for Congress, coordinated by Kevin J. Hickey, at 24–25
(2020).
5 See CRS Report R47267, Patents and Innovation Policy, by Emily G. Blevins, at 10 (2020).
6 See Jeffrey C. Totten, Four Strategies to Stay Litigation in Favor of IPR, FINNEGAN (May 2014),
https://www.finnegan.com/en/insights/articles/four-strategies-to-stay-litigation-in-favor-of-ipr.html.
7 H.R. REP. NO. 112-98, at 39–40 (2011), as reprinted in 2011 U.S.C.C.A.N. 67, 69.
8 H.R. REP. NO. 112-98, at 54 (“A number of patent observers believe the issuance of poor business-method patents
during the late 1990’s through the early 2000’s led to the patent ‘troll’ lawsuits that compelled the Committee to launch
the patent reform project 6 years ago.”).
9 See FTC, PATENT ASSERTION ENTITY ACTIVITY: AN FTC STUDY 15–17 (2016) (defining “patent assertion entity”);
Halo Elecs., Inc. v. Pulse Elecs., Inc., 579 U.S. 93, 109 (2016) (“Trolls, in the patois of the patent community, are
entities that hold patents for the primary purpose of enforcing them against alleged infringers, often exacting outsized
licensing fees on threat of litigation.”).
10 See Peter J. Pitts, “Patent Death Squads” vs. Innovation, WALL ST. J. (June 10, 2015, 7:23 PM),
https://www.wsj.com/articles/patent-death-squads-vs-innovation-1433978591.
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startups.11 PTAB critics also argue that administrative challenges to patents are unfair to patent
holders who have successfully obtained a patent through the USPTO patent prosecution process
but must now again defend their patent’s validity before USPTO.12
These stakeholder debates have led to proposed reforms to PTAB, both from USPTO itself and
from Members of Congress, including multiple bills introduced in the last several Congresses.
This report provides the legal background necessary to understand these debates and the practical
effects that changes to PTAB may have on technology and innovation.
This report begins with an overview of U.S. patent law, including what patents are, what kinds of
inventions may be patented, the process of obtaining a patent with USPTO, and how patent
owners may enforce their patent rights. It then discusses the AIA and its creation of PTAB,
including PTAB’s administrative structure. The report then explains and compares the three types
of post-grant proceedings established by the AIA, focusing on IPR, the most used of these
proceedings. The report follows with a discussion of several cases involving PTAB decided by
the Supreme Court. Finally, the report discusses current debates and proposed reforms of PTAB,
including standing, burdens of proof, discretionary institution of IPRs, claim construction, and the
role of the USPTO Director in reviewing PTAB decisions.
Overview of U.S. Patent Law
What Are Patents?
Patents are a form of intellectual property that give their holders the exclusive right to practice
their inventions (i.e., make, use, sell, offer to sell, or import them) for a limited period of time.
The Constitution gives Congress the power to grant patent rights to inventors by authorizing
Congress to “promote the Progress of Science and useful Arts, by securing for limited Times to . .
. Inventors the exclusive Right to their respective . . . Discoveries.”13 Since 1790, Congress has
enacted patent laws granting inventors certain exclusive rights in their inventions for a period of
time.14 (Currently, patents expire 20 years after the date that the patent application that gave rise
to the patent was filed.15) Patents represent a “quid pro quo” by which the inventor publicly
discloses an invention in exchange for time-limited, exclusive rights to practice it.16 In the United
States, USPTO is responsible for evaluating patent applications and granting patents on
qualifying inventions, as explained below.17

11 See, e.g., id.; ALLIANCE OF U.S. STARTUPS AND INVENTORS FOR JOBS, Why Patents Matter, https://www.usij.org/why-
patents-matter/ (last visited Mar. 28, 2024).
12 See, e.g., Gene Quinn, A Kinder, Gentler ‘Death Squad’: Ten Years in, Despite Some Reforms, the USPTO Is Still
Killing U.S. Patents, IP WATCHDOG (Sept. 19, 2021, 12:15 PM), https://ipwatchdog.com/2021/09/19/kinder-gentler-
death-squad-ten-years-despite-reforms-uspto-still-killing-u-s-patents/id=137765/; Oil States Energy Servs. v. Greene’s
Energy Grp., 584 U.S. 325, 345–47 (2018) (Gorsuch, J., dissenting).
13 U.S. CONST. art. I, § 8, cl. 8.
14 See, e.g., 35 U.S.C. § 271 (setting forth how patents may be infringed).
15 Id. § 154(a)(2). Patent terms can be extended in some circumstances, such as delays by USPTO in reviewing a patent
application. See id. §§ 154(b), 156.
16 J.E.M. Ag Supply, Inc. v. Pioneer Hi-Bred Int’l, Inc., 534 U.S. 124, 142 (2001) (“The disclosure required by the
Patent Act is ‘the quid pro quo of the right to exclude.’” (quoting Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 484
(1974))); see also Universal Oil Prods. Co. v. Globe Oil & Refin. Co., 322 U.S. 471, 484 (1944) (“As a reward for
inventions and to encourage their disclosure, the United States offers a . . . monopoly to an inventor who refrains from
keeping his invention a trade secret. But the quid pro quo is disclosure of a process or device in sufficient detail . . . .”).
17 See infra “How Do Inventors Obtain a Patent?”.
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Once granted, the holder of a valid patent has the exclusive right to make, use, sell, or import the
invention in the United States until the patent expires.18 Any other person who practices the
invention without permission from the patent holder infringes the patent and is liable for
monetary damages, and possibly subject to injunctive relief, if sued by the patentee.19 Patents
have the attributes of personal property, and the patentee may sell or assign the patent to another
person.20 A patentee may also license other persons to practice the invention, granting them
permission to make, use, sell, or import the invention, usually in exchange for consideration (such
as monetary royalties).21
What Inventions Can Be Patented?
In order to be patented, an invention must meet four substantive requirements: The invention
must be (1) directed to patentable (or “eligible”) subject matter, (2) new, (3) nonobvious, and
(4) useful.22 In addition to these four substantive patentability requirements, the Patent Act
imposes minimum requirements for the technical disclosure of the invention in the patent
application, which must adequately describe and distinctly claim the invention.23 As discussed in
this report, PTAB administers certain proceedings in which petitioners may seek to invalidate a
patent previously granted by USPTO on the grounds that the patent fails to satisfy certain of these
requirements. This section briefly surveys these patentability requirements.
Eligible Subject Matter Requirement
The Patent Act allows inventors to obtain patents on any new and useful “process, machine,
manufacture, or composition of matter, or . . . improvement thereof.”24 Examples of technological
areas for patentable inventions include pharmaceuticals, biotechnology, chemistry, computer
hardware and software, electrical engineering, mechanical engineering, and manufacturing
processes.25 By contrast, the Supreme Court has long held that “laws of nature, natural
phenomena, and abstract ideas” are not patentable.26 The Court has reasoned that to permit a
monopoly on the “‘basic tools of scientific and technological work’ . . . might tend to impede
innovation more than it would tend to promote it.”27
In a series of cases in the 2010s, the Supreme Court established a two-step test for patentable
subject matter, sometimes called the Alice test or the Alice/Mayo framework.28 The first step

18 35 U.S.C. § 271(a).
19 Id. §§ 271, 281, 283–285.
20 Id. § 261.
21 License, BLACK’S LAW DICTIONARY (10th ed. 2014); 35 U.S.C. § 271(a).
22 See 35 U.S.C. §§ 101–103.
23 Id. § 112; see generally Hickey, supra note 4, at 12–14.
24 35 U.S.C. § 101.
25 See USPTO, PATENT TECHNOLOGY CENTERS MANAGEMENT, https://www.uspto.gov/patent/contact-patents/patent-
technology-centers-management (last visited Mar. 28, 2024) (listing technological divisions for USPTO examiners).
26 Diamond v. Diehr, 450 U.S. 175, 185 (1981); see generally Hickey, supra note 4, at 10–20 (overviewing
development of the law of patent-eligible subject matter).
27 Mayo Collaborative Servs. v. Prometheus Lab’ys, Inc., 566 U.S. 66, 71 (2012) (quoting Gottschalk v. Benson, 409
U.S. 63, 67 (1972)).
28 See Alice Corp. Pty. Ltd. v. CLS Bank Int’l, 573 U.S. 208 (2014); Ass’n for Molecular Pathology v. Myriad
Genetics, Inc., 569 U.S. 576 (2013); Mayo Collaborative Servs., 566 U.S. at 66. USPTO has issued guidelines for its
patent examiners to determine whether a patent application seeks to claim ineligible subject matter. See 2019 Revised
Patent Subject Matter Eligibility Guidance, 84 Fed. Reg. 50 (Jan. 7, 2019).
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addresses whether the patent claims are “directed to” ineligible subject matter—a law of nature,
natural phenomenon, or abstract idea.29 If not, the invention is patentable. If directed at ineligible
subject matter, the invention is not patentable unless the patent claims have an “inventive
concept” under the second step of the Alice/Mayo test. To have an “inventive concept,” the patent
claims must contain elements “sufficient to ensure that the patent in practice amounts to
significantly more than a patent upon the [ineligible concept] itself,” transforming the nature of
the claim to a patent-eligible application of ineligible subject matter.30
Novelty Requirement
Perhaps the most fundamental requirement for patentability is that the claimed invention must be
novel (i.e., new). By statute, USPTO cannot issue a patent if “the claimed invention was patented,
described in a printed publication, or in public use, on sale, or otherwise available to the public
before the effective filing date of the claimed invention.”31 In other words, if every element of the
claimed invention is already disclosed in the prior art—the information available to the public at
the time of the patent application—then the alleged inventor “has added nothing to the total stock
of knowledge,” and no valid patent may issue to her.32
Nonobviousness Requirement
Even if a claimed invention is novel in the narrow sense that it is not “identically disclosed” in a
prior art reference (such as an earlier patent or publication), the invention must further be
nonobvious to be patentable.33 Specifically, an invention cannot be patented if “the differences
between the claimed invention and the prior art are such that the claimed invention as a whole
would have been obvious . . . to a person having ordinary skill” in the relevant technology.34
When determining obviousness, courts may evaluate considerations such as “commercial success,
long felt but unsolved needs, [or] failure of others . . . to give light to the circumstances
surrounding the origin of the subject matter sought to be patented.”35 By its nature, obviousness is
an “expansive and flexible” inquiry that cannot be reduced to narrow, rigid tests.36 That said, if an
invention merely combines “familiar elements according to known methods,” yielding only
“predictable results,” it is likely to be deemed obvious.37

29 Alice Corp., 573 U.S. at 217.
30 Id. (quoting Mayo Collaborative Servs., 566 U.S. at 73).
31 35 U.S.C. § 102(a)(1). There are certain exceptions to this requirement when, for example, the prior art disclosure
derives from the inventor and the patent application is made within one year of the disclosure. Id. § 102(b)(1).
32 Great Atl. & Pac. Tea Co. v. Supermarket Equip. Corp., 340 U.S. 147, 153 (1950); see Graham v. John Deere Co.,
383 U.S. 1, 6 (1966) (“Congress may not authorize the issuance of patents whose effects are to remove existent
knowledge from the public domain, or to restrict free access to materials already available.”).
33 35 U.S.C. § 103.
34 Id. Patent law frequently relies on the concept of a “person having ordinary skill in the art,” a “hypothetical person”
with a typical level of skill in the relevant technology who is “presumed to be aware of all the pertinent prior art” in the
particular field. See Standard Oil Co. v. Am. Cyanamid Co., 774 F.2d 448, 454 (Fed. Cir. 1985).
35 Graham, 383 U.S. at 17–18.
36 KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 415–19 (2007).
37 Id. at 416.
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Utility Requirement
An invention must also be useful to be patentable, which means that it must have a specific and
substantial utility.38 The utility requirement derives from the Constitution’s command that patent
laws exist to “promote the Progress of . . . useful Arts.”39 The constitutional purpose of patent law
thus requires a “benefit derived by the public from an invention with substantial utility,” where
the “specific benefit exists in currently-available form.”40 The bar for utility is low, requiring only
that the claimed invention have some “significant and presently available benefit to the public”
that “is not so vague as to be meaningless.”41
Requirements for Specification and Claims
Along with the four substantive requirements discussed above, the Patent Act imposes
requirements relating to the form of the patent application. These formal requirements pertain to
two key sections of the patent application, known as the claims and the specification, which
become part of the patent itself if the application is granted.
Section 112 of the Patent Act requires that patents contain a “specification” that includes
a written description of the invention, and of the manner and process of making and using
it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to
. . . make and use the same, and shall set forth the best mode contemplated by
the inventor or joint inventor of carrying out the invention.42
This statutory language yields three basic disclosure requirements for patentability.43 First, to
satisfy the written description requirement, the specification must “reasonably convey[] to those
skilled in the art that the inventor had possession of the claimed subject matter as of the filing
date” of the patent application.44 Second, to satisfy the enablement requirement, the specification
must contain enough information to teach a person skilled in the art how “to make and use the
invention without undue experimentation.”45 Finally, to satisfy the best mode requirement, the
specification must show that the inventor “possessed a best mode for practicing the invention” at
the time of the patent application, and disclose that preferred way of practicing the invention.46
These disclosure requirements ensure that the patent adequately discloses the invention to the
public so that the public can use the invention after the patent term expires.47
If granted, the patent’s legal scope is defined by the patent claims, which are words that
“particularly point[] out and distinctly claim[] the subject matter which the inventor . . . regards as
the invention.”48 In essence, while the specification explains the invention in a technical sense,

38 Brenner v. Manson, 383 U.S. 519, 534–35 (1966); In re Fisher, 421 F.3d 1365, 1371 (Fed. Cir. 2005).
39 Stiftung v. Renishaw PLC, 945 F.2d 1173, 1180 (Fed. Cir. 1991) (citing Brenner, 383 U.S. at 528–29); see also
Graham, 383 U.S. at 5–6.
40 Brenner, 383 U.S. at 534–35.
41 In re Fisher, 421 F.3d at 1371–72.
42 35 U.S.C. § 112(a) (emphasis added).
43 See Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 736 (2002); Ariad Pharms., Inc. v. Eli
Lilly & Co., 598 F.3d 1336, 1344 (Fed. Cir. 2010) (en banc).
44 Ariad Pharms., 598 F.3d at 1351.
45 In re Wands, 858 F.2d 731, 735 (Fed. Cir. 1988).
46 Eli Lilly & Co. v. Barr Lab’ys, Inc., 251 F.3d 955, 963 (Fed. Cir. 2001).
47 See Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 480–81 (1974).
48 35 U.S.C. § 112(b).
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the claims set forth the patent’s legal effect.49 Much as a deed may describe the boundaries of a
tract of land, the claims define the “metes and bounds” of the patent right.50 Patent claims must be
sufficiently definite to be valid—that is, when the claims are read in context, they must “inform,
with reasonable certainty, those skilled in the art about the scope of the invention.”51 This
requirement is designed to give the public clear notice of what is and is not covered by the patent
claims.
How Do Inventors Obtain a Patent?
The process for receiving a patent begins with the filing of an application with USPTO.52 A
USPTO patent examiner then reviews the application for compliance with the legal requirements
for receiving a patent.53 If the examiner determines that the application does not meet one of the
requirements, she will reject the application.54 The applicant may generally then amend the
application in an effort to overcome the examiner’s rejection.55 Once the examiner determines
that an application meets all of the patentability requirements, she “allows” the application to
issue as a patent.56
Patent prosecution is the process of applying for a patent, addressing examiner concerns, and—if
successful—receiving the patent.57 USPTO examiners are generally not lawyers, but rather are
subject specialists in the relevant science and/or technology area.58 Accordingly, USPTO issues
the Manual of Patent Examining Procedure (MPEP) to provide guidance for examiners and
practitioners.59
How Do Courts Adjudicate Patent Rights?
Patents are not self-enforcing: to obtain relief from infringement, the patentee must sue in court.60
Patent law is an area of exclusive federal jurisdiction,61 and the traditional forum for patent

49 See Ariad, 598 F.3d at 1347 (Fed. Cir. 2010); In re Vamco Mach. & Tool, Inc., 752 F.2d 1564, 1577 n.5 (Fed. Cir.
1985).
50 Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868 F.2d 1251, 1257 (Fed. Cir. 1989).
51 Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014).
52 See generally 35 U.S.C. § 111.
53 See JAMES E. HAWES & FREDERIC M. DOUGLAS, PATENT APPLICATION PRACTICE § 2:4 (2020) (providing an overview
of the patent application process); USPTO, General Information Concerning Patents (Oct. 2015),
https://www.uspto.gov/patents-getting-started/general-information-concerning-patents.
54 HAWES & DOUGLAS, supra note 53, § 14:2.
55 Id. § 15.7−15.19.
56 Id. § 21.1.
57 Nick Cornor, Are Changes to the U.S. Patent System Objectively Killing Innovation?, 24 CURRENTS: J. INT’L ECON.
L. 87, 90 (2020) (“Patent prosecution refers to the process of applying for a patent.”). Although the foregoing
discussion provides a high-level overview of the process, patent prosecution is governed by specific laws and
regulations, the detailed discussion of which could fill its own report. See generally HAWES & DOUGLAS, supra note 53.
58 Lital Helman, Decentralized Patent System, 20 NEV. L.J. 67, 89 (2019) (“PTO examiners are not lawyers.”); cf. Greg
Reilly, Decoupling Patent Law, 97 B.U. L. REV. 551, 592 (2017) (“Inherently legal tasks—like parsing the wording of
documents, analogizing and distinguishing precedent, and applying canons of document interpretation—are better
suited for legally trained judges than legally limited patent examiners.”).
59 See USPTO, Manual of Patent Examining Procedure (9th ed. July 2022), https://www.uspto.gov/web/offices/
pac/mpep/index.html [hereinafter MPEP].
60 35 U.S.C. § 281.
61 28 U.S.C. § 1338.
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disputes is federal district court.62 Although patent suits may be filed in any district court across
the country with jurisdiction over the defendant and proper venue, all appeals in patent cases are
heard by a single specialized court, the U.S. Court of Appeals for the Federal Circuit (the Federal
Circuit).63
Once accused of infringement in a district court case, the defendant may claim an “absence of
liability” based on noninfringement.64 In other words, the patentee may fail to prove that the
activities of the accused infringer fall within the scope of the patent claims.65
Parties accused of patent infringement may also rely on several affirmative defenses, which are
grounds on which the defendant—not the plaintiff—bears the burden of proof. First, although
patents are subject to a presumption of validity, the accused infringer may assert that the patent is
invalid.66 To prove invalidity, the accused infringer must show, by clear and convincing evidence,
that USPTO should not have granted the patent because the patent failed to meet the statutory
requirements for patentability.67 Thus, for example, the accused infringer may argue that the
invention lacks novelty, is obvious, or claims nonpatentable subject matter; that the patent fails to
enable the invention; or that the patent claims are indefinite.68
In addition, the accused infringer may argue the patent is unenforceable based on the patent
holder’s inequitable or illegal activities, such as obtaining the patent through fraud on USPTO.69
All of these legal arguments are generally evaluated on a claim-by-claim basis—that is, a court
may find that some of the patent’s claims are valid but other claims are invalid, or that the
defendant infringes some of the patent’s claims but not others, for example.
Both patent infringement and patent validity determinations turn in part on the meaning and scope
of a patent’s claims,70 which define the boundaries of the patentee’s intellectual property right.
For instance, if a patent’s claims are interpreted broadly, it may be easier for the plaintiff to prove
that the defendant’s products or activities infringe that patent. On the other hand, interpreting

62 In 2023, roughly 3,108 patent lawsuits were filed in federal district courts. See 2023 Patent Dispute Report: Year in
Review, UNIFIED PATENTS (Jan. 8, 2024), https://www.unifiedpatents.com/insights/2024/1/8/patent-dispute-report-
2023-in-review. An additional forum for patent infringement disputes is the ITC, which has authority to conduct
administrative trials into whether imported goods violate patent and other IP rights. See 19 U.S.C. § 1337. The ITC
may issue exclusion orders to stop such goods from entering the United States. See CRS In Focus IF12295, An
Introduction to Section 337 Intellectual Property Litigation at the U.S. International Trade Commission, by
Christopher T. Zirpoli (2024). The ITC typically initiates several dozen Section 337 investigations per year. See Section
337 Statistics: Number of New, Completed, and Active Investigations by Fiscal Year, ITC (last updated Oct. 12, 2023),
https://www.usitc.gov/intellectual_property/337_statistics_number_new_completed_and_active.htm (reporting fifty-
five new complaints in Fiscal Year 2023).
63 28 U.S.C. § 1295(a)(1).
64 35 U.S.C. § 282(b)(1).
65 To prove direct infringement, the plaintiff must show that each element contained in a patent claim is practiced by
the alleged infringer, either literally or by an equivalent. Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S.
17, 29–30 (1997).
66 35 U.S.C. § 282(a)–(b).
67 Id. § 282(b)(2)–(3); Microsoft Corp. v. i4i LP, 564 U.S. 91, 95–96 (2011).
68 35 U.S.C. §§ 101, 102–103, 112, 282(b)(2)–(3).
69 Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1285, 1290–91 (Fed. Cir. 2011) (en banc).
70 MPHJ Tech. Invs., LLC v. Ricoh Ams. Corp., 847 F.3d 1363, 1364 (Fed. Cir. 2017) (“[T]he first step in any validity
analysis is to construe the claims of the invention to determine the subject matter for which patent protection is sought.”
(quoting Smiths Indus. Med. Sys., Inc. v. Vital Signs, Inc., 183 F.3d 1347, 1353 (Fed. Cir. 1999))); Nazomi Commc’ns,
Inc. v. Nokia Corp., 739 F.3d 1339, 1343 (Fed. Cir. 2014) (“The first step of the infringement analysis is claim
construction . . . .”); see also TVIIM, LLC v. McAfee, Inc., 851 F.3d 1356, 1362 (Fed. Cir. 2017) (“Claim terms must
be construed the same way for the purpose of determining invalidity and infringement.”).
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claims broadly may make it easier for the defendant to show that the claims are invalid because
they were anticipated or obvious in light of prior art. When the parties dispute how patent claims
should be interpreted, the judge must decide how to construe the disputed claim terms.71 The
process for determining the meaning of a disputed patent claim term is referred to as claim
construction.72 While claim construction is a question of law decided by the judge,73 the ultimate
issue of whether the accused product(s) infringe the patent claims, as construed by the judge, is a
question of fact generally tried to a jury.74
What Was USPTO’s Role in Patent Adjudication Prior to the AIA?
In addition to asserting invalidity as an affirmative defense to a patent infringement lawsuit in
district court, a person may petition to invalidate an issued patent in various administrative
proceedings known as post-grant proceedings, which are administered by USPTO.75 Before the
AIA was enacted, the available post-grant proceedings included ex parte reexamination and inter
partes reexamination.
Ex parte reexamination, the longest-standing post-grant proceeding, allows “[a]ny person at any
time” (including the patent owner herself) to request that USPTO reexamine an issued patent.76
The request must be based on “patents or printed publications which that person believes to have
a bearing on the patentability of any claim of a particular patent.”77 If the USPTO Director
determines that the request raises “a substantial new question of patentability affecting any claim
of the patent,” then she may institute an ex parte reexamination.78 If a reexamination is initiated, it
proceeds in the same manner as the initial patent examination; in other words, the examiner may
reject the claims on the basis of the new prior art, the applicant may amend the claims, et cetera.79
Claim terms are given their broadest reasonable construction consistent with the specification (as
in the initial examination).80 The person who sought reexamination, however, is not involved in
the process once USPTO decides to initiate reexamination.

71 Markman v. Westview Instruments, Inc., 517 U.S. 370, 372 (1996) (“We hold that the construction of a patent,
including terms of art within its claim, is exclusively within the province of the court.”).
72 Netword, LLC v. Centraal Corp., 242 F.3d 1347, 1352 (Fed. Cir. 2001) (“‘Claim construction’ is the judicial
statement of what is and is not covered by the technical terms and other words of the claims.”); see also Abbott Lab’ys
v. Sandoz, Inc., 544 F.3d 1341, 1358 (Fed. Cir. 2008) (“The first step in most infringement suits is the procedure called
‘claim construction,’ where the scope of the claim is defined by the court.”); Pall Corp. v. Hemasure, Inc., 181 F.3d
1305, 1308 (Fed. Cir. 1999) (“Analysis of patent infringement starts with ‘construction’ of the claim, whereby the court
establishes the scope and limits of the claim, interprets any technical or other terms whose meaning is at issue, and
thereby defines the claim with greater precision than had the patentee.”).
73 See Markman, 517 U.S. at 372.
74 See Apple Inc. v. Samsung Elecs. Co., 839 F.3d 1034, 1040 (Fed. Cir. 2016) (en banc) (reviewing jury verdict of
infringement).
75 Although the terminology is different, there is no practical difference between a district court invalidating a claim
during litigation and USPTO cancelling a claim following an administrative proceeding. The result is the same: the
patent can no longer be enforced.
76 35 U.S.C. § 302.
77 Id. § 301(a)(1).
78 Id. § 303(a). The USPTO Director may also determine whether a substantial new question of patentability exists on
her own initiative. Id.
79 Id. § 305. For more detail regarding initial examination, see Hickey, supra note 4, at 8–9.
80 In re Man Mach. Interface Techs. LLC, 822 F.3d 1282, 1286 (Fed. Cir. 2016) (“In reexamination, claims are given
their broadest reasonable interpretation . . . consistent with the specification.”).
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In 1999, inter partes reexamination was added as an available post-grant proceeding for persons
to challenge granted patents.81 Inter partes reexamination provided third-party requesters the
ability to participate to a limited extent in a reexamination through comments and declarations
submitted during the reexamination proceedings.82 Third-party requestors who sought inter partes
reexamination were later estopped from alleging that a patent was invalid based on any grounds
that could have been raised in the reexamination.83
The AIA eliminated inter partes reexamination and created two currently available adversarial
post-grant proceedings—known as inter partes review and post-grant review—and established
PTAB to administer them. The following sections discuss in depth the AIA, PTAB, and the new
post-grant proceedings.
Overview of the America Invents Act and PTAB
In 2011, Congress passed the AIA, a major reform of U.S. patent law. Among the most important
changes made in the AIA were the creation of PTAB and the new post-grant proceedings for
PTAB to administer. This section provides an overview of the key provisions of the AIA and the
administrative structure it established for PTAB.
The AIA’s Key Changes to Patent Law
Under the AIA, PTAB replaced a body known as the Board of Patent Appeals and
Interferences (BPAI), which ceased to exist when PTAB began operations in 2012.84 PTAB took
over BPAI’s responsibility for hearing appeals from USPTO rejections of patent applications.85
PTAB also took over BPAI’s responsibility for hearing appeals from rejections of patent owners’
claims in ex parte reexaminations.86
The AIA replaced inter partes reexamination with two new administrative proceedings—inter
partes review (IPR) and post-grant review (PGR)—administered by PTAB. The AIA also created
a transitional program to challenge covered business method (CBM) patents, which expired in
2020. These proceedings are discussed in detail below.87
In addition, the AIA effected a major change to U.S. patent law with respect to priority, or who is
entitled to a patent when different people claim to have invented the same thing at around the
same time.88 Previously, the first person to invent a particular invention was generally given
priority in obtaining a patent when two different people filed patent applications on the same
invention.89 The AIA provides that for applications filed on or after March 16, 2013, the first

81 American Inventors Protection Act of 1999, Pub. L. No. 106-113.
82 MPEP, supra note 59, §§ 2609, 2654.
83 35 U.S.C. § 315(c) (2011).
84 U.S. GOV’T ACCOUNTABILITY OFF., GAO-22-106121, PATENT TRIAL AND APPEAL BOARD: PRELIMINARY
OBSERVATIONS ON OVERSIGHT OF JUDICIAL DECISIONMAKING 1 n.1 (2022).
85 35 U.S.C. § 134(a) (allowing applicant to appeal to PTAB after “claim[] has been twice rejected”).
86 35 U.S.C. § 134(b) (allowing owner to appeal to PTAB from “final rejection” in a reexamination). BPAI had also
overseen appeals from inter partes reexamination proceedings.
87 See infra “PTAB Post-Grant Proceedings.”
88 See SNIPR Techs. Ltd. v. Rockefeller Univ., 72 F.4th 1372, 1374 (Fed. Cir. 2023) (“‘Patent priority’ establishes who
is entitled to a patent on a particular invention claimed by different parties.”).
89 Leahy-Smith America Invents Act, Pub. L. No. 112-29, § 3(n)–(o), 125 Stat. 284, 293 (2011).
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inventor to file an application with USPTO is regarded as the inventor.90 The AIA thus changed
the United States from a first-to-invent to a first-to-file jurisdiction,91 consistent with the rest of
the world.92 In addition to international uniformity, Congress sought to make priority
determinations more “objective and simple” by changing to a first-to-file system.93 (Generally
speaking, it is simpler to determine when a person filed a patent application than when a person
conceived of a particular idea and reduced it to practice.)
To match the change to a first-to-file patent system, the AIA overhauled proceedings for
contesting priority. Previously, if a person claimed to have invented something earlier than the
patent applicant, that person could contest ownership of the patent via a challenge known as an
interference, which could be asserted in administrative proceedings decided by BPAI or in district
court.94 The AIA left interferences in place for patents filed prior to March 16, 2013 (i.e., under
the first-to-invent regime),95 and transferred responsibility for those proceedings to PTAB.96 For
patents filed on or after March 16, 2013, interference proceedings “are no longer necessary
because it is now the first filer—not the first inventor—who has priority and is entitled to a
patent.”97
For patents filed on or after March 16, 2016, the AIA replaced interference with derivation, a
challenge that may be asserted in proceedings decided by PTAB or in district court litigation.98
Whereas interference allowed a challenger to take priority over a patent by showing that the
challenger had invented the claimed subject matter before the patentee, derivation requires the
challenger to show that an earlier patent filer derived the invention from the challenger (i.e., the
patentee took the idea from the challenger as opposed to inventing it independently).99 Derivation
is used infrequently, with one survey counting fewer than two dozen derivation petitions filed at
USPTO between 2013 and 2022.100
PTAB’s Structure
The AIA provides that PTAB consists of the USPTO Director and Deputy Director, the
Commissioner for Patents, the Commissioner of Trademarks, and an unspecified number of

90 Id.; see also 35 U.S.C. § 102.
91 See SNIPR Techs., 72 F.4th at 1373.
92 See id. at 1375 (“The U.S. was the last remaining country in the world to use a first-to-invent system.”).
93 Id. at 1374. Consistent with the new first-to-file system, the AIA amended the definitions of prior art and
obviousness so that both would be assessed as of the filing date rather than the time of invention. See id. at 1375.
94 See id. at 1375.
95 See id. at 1376; Biogen MA, Inc. v. Japanese Found. for Cancer Rsch., 785 F.3d 648, 655 (Fed. Cir. 2015) (noting
“interference proceedings are to continue with respect to . . . applications filed before March 16, 2013”).
96 The AIA also left interference in place for patents that contain at least one claim each with pre- and post-March 16,
2013, effective filing dates. See SNIPR Techs., 72 F.4th at 1376. In SNIPR Techs., the Federal Circuit held that “pure
AIA patents” with no claims having pre-March 16, 2013, filing dates may not be subjected to interference, including
where the alleged basis for prior inventorship is a pre-AIA patent. See id. at 1374.
97 Id. at 1374.
98 See 35 U.S.C. § 135 (derivation proceedings decided by PTAB), § 291 (derivation asserted in district court); SNIPR
Techs., 72 F.4th at 1375–76 (“AIA . . . repealed interferences in pre-AIA §§ 135 and 291 . . . .”).
99 See SNIPR Techs., 72 F.4th at 1376 (“Whereas interference proceedings determined who was the first inventor,
derivation proceedings determine whether the earlier filer had derived the claimed invention from a later filer.”).
100 See Barbra Clarke McCurdy et al., Spotted: The Rare AIA Derivation Proceeding!, FINNEGAN (April 22, 2022),
https://www.finnegan.com/en/insights/blogs/at-the-ptab-blog/spotted-the-rare-aia-derivation-proceeding.html.
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administrative patent judges (APJs).101 Currently, PTAB employs more than 200 APJs.102 PTAB is
divided into a Trial Division and an Appeals Division. The Trial Division administers post-grant
proceedings created by the AIA, while the Appeals Division hears appeals of patent prosecution
decisions.
The Secretary of Commerce, in consultation with the USPTO Director, appoints the APJs to serve
on PTAB.103 The AIA requires that APJs be “persons of competent legal knowledge and scientific
ability.”104 The Director, who is appointed by the President with advice and consent of the Senate,
is a member of PTAB and maintains a degree of authority over the APJs.105 The AIA gives the
Director authority to select the three-member APJ panels who decide IPRs106 and to issue
regulations governing the conduct of PTAB proceedings,107 although in practice the Director has
delegated panel selection to a Chief Judge.108 The AIA also gives the Director authority to
designate selected written decisions as precedential and thus binding on future panels of APJs.109
APJs cannot be removed without cause.110
PTAB Post-Grant Proceedings
As noted above, the AIA charged PTAB with administering three new types of post-grant
proceedings for challenging the validity of patents previously issued by USPTO. One of these
proceedings, CBM review, sunset in 2020 pursuant to the AIA. The other two—IPR and PGR—
have no sunset provision and are regularly used.
This section provides an overview and comparison of IPR, PGR, and CBM reviews. The
discussion focuses principally on IPR, which has been both the most used type of PTAB
proceeding and the target of many current reform efforts, which are discussed in the final section
of the report.111
Inter Partes Review
IPR is the most-used type of post-grant proceeding introduced by the AIA by an overwhelming
margin.112 This section discusses the statutory requirements for filing an IPR, PTAB’s discretion
whether to institute IPRs, and the IPR process.

101 35 U.S.C. § 6(a).
102 U.S. GOV’T ACCOUNTABILITY OFF., GAO-23-105336, PATENT TRIAL AND APPEAL BOARD: INCREASED
TRANSPARENCY NEEDED IN OVERSIGHT OF JUDICIAL DECISION-MAKING 14 (2022), at 5 [hereinafter GAO PTAB
REPORT].
103 35 U.S.C. § 6(a).
104 Id.
105 See id.
106 Id. § 6(c).
107 Id. § 6(b)(2).
108 USPTO, PATENT TRIAL AND APPEAL BOARD: STANDARD OPERATING PROCEDURE 1 (rev. 15),
https://www.uspto.gov/sites/default/files/documents/SOP%201%20R15%20FINAL.pdf [hereinafter SOP 1].
109 See USPTO, PATENT AND TRIAL APPEAL BOARD: STANDARD OPERATING PROCEDURE 2 (rev. 11) (July 24, 2023),
https://www.uspto.gov/sites/default/files/documents/20230724_ptab_sop2_rev11_.pdf.
110 35 U.S.C. § 3(c); 5 U.S.C. § 7513(a); see also United States v. Arthrex, Inc., 594 U.S. 1, 16–17 (2021).
111 See infra “Current Debates and Proposed Reforms.”
112 See USPTO, PTAB TRIAL STATISTICS: FY23 END OF YEAR OUTCOME ROUNDUP—IPR, PGR 3,
https://www.uspto.gov/sites/default/files/documents/ptab_aia_fy2023__roundup.pdf (last visited Mar. 28, 2024)
[hereinafter PTAB FY23 STATISTICS].
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Standing, Timing, and Grounds to Petition for IPR
Any person other than the patent owner may file a petition requesting that PTAB institute (i.e.,
proceed with) an IPR.113 An IPR petition may be filed at any time starting nine months after the
patent issues through the time the patent expires.114 If the petitioner or their “real party in
interest[] or privy” is sued for infringement of the patent, the petitioner may not file the petition
any later than one year after they are served with the infringement complaint.115
An IPR petition may challenge the validity of patent claim on only two bases—anticipation (35
U.S.C. § 102) or obviousness (35 U.S.C. § 103).116 It may not challenge patentability for other
reasons, such as whether the patent claims eligible subject matter (35 U.S.C. § 101) or is not
enabled (35 U.S.C. § 112). The IPR petition may rely only on prior art patents or printed
publications.117 Other forms of prior art, such as public uses or sales of the claimed invention,
cannot be a basis for IPR.118
An IPR petition must also meet a number of procedural requirements. For example, the petitioner
must identify all real parties-in-interest; identify the challenged patent claims and the grounds for
the challenge “with particularity”; and pay a fee set by USPTO.119
Discretionary Institution of IPR
The AIA makes the USPTO Director responsible for deciding whether or not to institute an
IPR.120 The Director is charged with making this decision based on the challenger’s petition as
well as an optional preliminary response that the patent owner may choose to file within three
months of the petition.121 The Director must determine whether to institute the IPR within three
months of receiving the preliminary response (or three months after the last date on which such a
response could be filed).122 The Director has delegated all IPR institution decisions to PTAB.123
When an IPR petition is filed, a panel of three APJs is assigned to the case, and it is this panel that
makes the institution decision.124 Thus, references to the “Director” in the provisions of the AIA
regarding institution now refer, in practice, to a PTAB panel of three APJs.
The AIA does not permit PTAB to institute an IPR unless it determines that the petition and any
preliminary response “shows that there is a reasonable likelihood that the petitioner would prevail
with respect to at least 1 of the claims challenged in the petition.”125 Nonetheless, the AIA does
not require PTAB to institute an IPR if this threshold is satisfied, and it provides that “[t]he

113 35 U.S.C. § 311(a).
114 Id. § 311(c). If a PGR is instituted with respect to the patent, an IPR may not be filed until the PGR concludes. Id.
115 Id. § 315(b). A “real party in interest” refers to the “person entitled under the substantive law to enforce the right
sued on.” Real party in interest, BLACK’S LAW DICTIONARY (11th ed. 2019). A “privy” refers to “someone who controls
a lawsuit though not a party to it; someone whose interests are represented by a party to the lawsuit; and a successor in
interest to anyone having a derivative claim.” Privy, BLACK’S LAW DICTIONARY (11th ed. 2019).
116 35 U.S.C. § 311(b).
117 Id. § 311(b).
118 Cf. id. § 102(a)(1).
119 Id. § 312.
120 Id. § 314(a).
121 See id. §§ 313, 314; 37 C.F.R. § 42.107(a)–(b).
122 35 U.S.C. § 314(b).
123 37 C.F.R. § 42.108.
124 See GAO PTAB REPORT, supra note 102, at 8; SOP 1, supra note 108, at 1.
125 35 U.S.C. § 314(a).
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determination by the Director whether to institute an inter partes review under this section shall
be final and nonappealable.”126
The AIA also prohibits institution of IPR in specific situations regarding related district court and
PTAB proceedings. First, the AIA provides that an IPR may not be instituted if, prior to the filing
of the petition, the petitioner or “real party in interest” filed a district court action (i.e., a
declaratory judgment action127) challenging any claim of the same patent.128 Thus, a party cannot
file a district court case requesting a declaratory judgment of invalidity and then file an IPR
petition challenging any claims of the same patent.
Second, the AIA contains an estoppel provision that prohibits some so-called serial petitions,
which are discussed in greater depth below.129 The estoppel provision states that, once an IPR
results in a final written decision, the petitioner (or their real party in interest or privy) cannot
“request or maintain” any other USPTO “proceeding” (including IPR) with respect to the same
patent claim based on “any ground that the petitioner raised or reasonably could have raised” in
the original IPR.130 The estoppel provision does not, however, prevent the petitioner from filing a
second IPR petition regarding the same patent claim(s) prior to a final written decision on the first
IPR. It also does not prevent a petitioner from filing a second IPR petition regarding different
claims in the same patent.
Through guidance and PTAB precedent, USPTO has developed guidelines for PTAB’s decisions
whether or not to institute IPRs in cases where none of the above-noted prohibitions on IPRs
apply.131 These guidelines address common scenarios such as serial IPR petitions and parallel
district court proceedings. The guidelines—and related reforms proposed by certain Members of
Congress and USPTO itself—are explained in more detail in the final section of this report.
IPR Process Following Institution
The framers of the AIA intended for IPR to serve as a faster, less costly alternative to district
court litigation.132 The AIA itself sets forth certain requirements for conducting and deciding IPR
proceedings.133 As directed by the AIA,134 USPTO has supplemented those requirements by
promulgating more detailed rules on PTAB trial practice and procedure.135 PTAB also provides

126 Id. § 314(d) (the “no-appeal provision”).
127 Cf. id. § 315(a)(3) (providing that this prohibition does not apply where the petitioner is sued for infringement and
responds with “[a] counterclaim challenging the validity of a claim”).
128 See id. § 315(a)(1).
129 See infra “Serial Petitions.”
130 35 U.S.C. § 315.
131 See, e.g., Memorandum from USPTO Director Katherine K. Vidal to PTAB, Interim Procedure for Discretionary
Denials in AIA Post-Grant Proceedings with Parallel District Court Litigation (June 21, 2022),
https://www.uspto.gov/sites/default/files/documents/interim_proc_discretionary_denials_aia_parallel_district_court_liti
gation_memo_20220621_.pdf.
132 See H.R. REP. NO. 112-98, at 39–40 (2011) (stating that among the goals of the AIA were to “improv[e] patent
quality and provid[e] a more efficient system for challenging patents that should not have issued” and to “limit
unnecessary and counterproductive litigation costs”).
133 35 U.S.C. §§ 316–319.
134 Id. § 316(a) (“The Director shall prescribe regulations . . . .”).
135 See 37 C.F.R. pt. 42.
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guidance on its standard practices for conducting these proceedings in its Consolidated Trial
Practice Guide.136
Once an IPR is instituted, PTAB issues a scheduling order setting forth key dates and deadlines.
The patent owner is given time to file a response to the petition—regardless of whether the
patentee filed a preliminary response before institution—followed by sur-replies by each party to
address any new arguments.137
During the IPR, the patent owner may also file a motion either to cancel any challenged claims or
to amend claims by “propos[ing] a reasonable number of substitute claims” for each such
challenged claim that would not “enlarge the scope” of the existing claims.138 In March 2024,
USPTO issued a notice of proposed rulemaking that would formalize a pilot program that it
established in 2019 to give patent holders additional options when filing a motion to amend
(MTA) their claims.139 Under this pilot program (and the proposed rule), patent holders may
request “preliminary, non-binding guidance” from PTAB on the merits of an MTA.140 Patent
holders may also file either a revised MTA or a reply brief in support of the original MTA
following the petitioner’s opposition and any preliminary guidance from PTAB.141 Patent holders
have had more success amending claims in AIA proceedings since the pilot program began in
2019. USPTO notes that 24% of final determinations have granted at least one substitute claim
during the pilot program, versus 14% previously.142
The petitioner in an IPR has the burden of proving unpatentability of challenged claims by a
preponderance of the evidence.143 As in district court litigation, PTAB may need to resolve
disagreements about claim construction (i.e., the interpretation of patent claims) in order to reach
a decision as to their validity.144 PTAB currently applies the same claim construction standard
used in district court litigation,145 which requires PTAB to construe claim terms according to their
“ordinary and customary meaning . . . to a person of ordinary skill in the art in question at the
time of the invention.”146 To discern this meaning, PTAB must look to the claims themselves, the
patent specification, documents from the prosecution of the patent (prosecution history), and, to a
lesser degree, “extrinsic evidence” such as expert testimony, dictionaries, and treatises.147

136 PTAB, CONSOLIDATED TRIAL PRACTICE GUIDE (Nov. 2019),
https://www.uspto.gov/sites/default/files/documents/tpgnov.pdf [hereinafter CONSOLIDATED PTAB PRACTICE GUIDE].
137 37 C.F.R. § 42.107, 42.120; CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136, at 73–75.
138 35 U.S.C. § 316(d).
139 Motion to Amend Practice and Procedures in Trial Proceedings Under the America Invents Act Before the Patent
Trial and Appeal Board, 89 Fed. Reg. 15531 (Mar. 4, 2024). In addition to IPR, the pilot program and proposed rule
apply to PGR and derivation proceedings. See id.
140 Id. at 15532.
141 See id.
142 See id. at 15533.
143 35 U.S.C. § 316(e).
144 See supra “How Do Courts Adjudicate Patent Rights?”.
145 See Changes to the Claim Construction Standard for Interpreting Claims in Trial Proceedings Before the Patent Trial
and Appeal Board, 83 Fed. Reg. 51340 (Oct. 11, 2018) (codified at 37 C.F.R. § 42.100(b)); Personalized Media
Commc’ns, LLC v. Apple Inc., 952 F.3d 1336, 1340 n.2 (Fed. Cir. 2020) (“Per recent regulation, [PTAB] applies the
Phillips claim construction standard to IPR petitions filed on or after November 13, 2018.”).
146 Phillips v. AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005).
147 See id. at 1313–19.
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As discussed below,148 some reform efforts seek to eliminate USPTO’s authority to depart from
the currently used claim construction standard, in light of the fact that PTAB previously employed
a different standard.
Discovery in IPR
Parties to an IPR may obtain evidence through discovery, although the scope of available
discovery is narrower than in district court litigation. The AIA largely defers to USPTO to “set[]
forth standards and procedures for discovery,”149 specifying only that discovery shall be limited to
“the deposition of witnesses submitting affidavits or declarations”150 and “what is otherwise
necessary in the interest of justice.”151 USPTO has promulgated rules requiring each party, at a
minimum, to provide “routine discovery” comprising the disclosure of any exhibit cited by the
party, disclosure of nonprivileged information inconsistent with the party’s litigation positions,
and making witnesses who submit affidavits available for cross-examination.152
Under USPTO rules, the parties may also conduct discovery via “mandatory initial disclosures.”
Despite their name, these “mandatory” disclosures are required only if the parties agree to them
or, barring agreement, if PTAB grants a party’s motion to require them.153 The parties may agree
either on narrow initial disclosures modeled on those required in district court litigation154 or on a
“more extensive” set of disclosures focusing on nonpublished prior art and secondary indicia of
nonobviousness, as set forth in the Consolidated Trial Practice Guide.155 If the IPR is instituted,
the parties may “automatically” take further discovery regarding information identified in
mandatory initial disclosures.156
Parties may agree or move to conduct additional discovery “in the interests of justice.”157 When
determining whether additional discovery is in the interests of justice, PTAB looks to five factors,
known as the Garmin factors: (1) whether there is more than a “mere possibility” or “mere
allegation” that useful information will be found; (2) whether the discovery request is a pretext to
seek the other party’s litigation positions or contentions; (3) whether the requesting party can
obtain the information by other means; (4) whether the discovery request is “easily
understandable”; (5) and whether the request is overly burdensome.158 Finally, parties may move
to request authorization to compel testimony or documents from third parties, similar to issuing a
subpoena in a civil lawsuit.159

148 See infra “Claim Construction: Should USPTO or Congress Decide the Right Standard?”.
149 35 U.S.C. § 316(a)(5).
150 Id. § 316(a)(5)(A).
151 Id. § 316(a)(5)(B).
152 37 C.F.R. § 42.51(b)(1).
153 Id. § 42.51(a)(1), (2).
154 CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136, at 29 (citing Fed. R. Civ. P. 26(a)(1)(A)).
155 See id. at 30–31.
156 37 C.F.R. § 42.51(a)(1)(ii).
157 Id. § 42.51(a)(2)(i).
158 See CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136, at 25–28 (citing Garmin Int’l, Inc. v. Cuozzo Speed
Techs. LLC, Case IPR2012-00001 (P.T.A.B. Mar. 5, 2013) (Paper 26) (precedential)).
159 37 C.F.R. § 42.52(a).
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IPR Final Decisions, Director Review, and Appeals
PTAB may decide an IPR based solely on written submissions by the parties, although the parties
may request an oral hearing before the three-APJ panel.160 A typical hearing consists of about an
hour of oral argument from each side.161 Although usually the hearing solely involves attorney
argument, live witness testimony may also be presented at the discretion of the panel.162
PTAB must issue a final written decision within one year after it institutes the IPR, although this
deadline may be extended by up to six months for “good cause.”163 Final written decisions must
address the patentability of each claim challenged by the petition, as well as any substitute claims
sought to be added by the patentee.164 Final decisions are accompanied by publication of a
certificate that cancels or confirms each claim depending on whether PTAB finds it to be
patentable; the certificate may also incorporate into the patent any patentable new or amended
claims.165 If the patent owner and any petitioner reach a settlement with one another prior to the
final written decision, they may request to terminate the IPR as to that petitioner by filing a
motion to terminate and the settlement agreement.166 If no petitioners remain in the IPR, PTAB
may choose either to terminate the IPR or to proceed to a final written decision.167
As originally enacted, the AIA allowed for parties to seek rehearing of a decision in an IPR only
from PTAB itself.168 As discussed below, following a 2021 Supreme Court decision, parties may
instead request review of final PTAB panel decisions by the USPTO Director.169 In addition, final
PTAB decisions (or denials of rehearing of a final decision) may be appealed to the Federal
Circuit.170 Any of the parties to the IPR have a right to be a party to such an appeal.171 The
USPTO Director may also intervene in the appeal to defend PTAB’s decision, regardless of
whether any party does so.172 PTAB’s decision to institute an IPR or not, however, is not
appealable.173

160 Id. § 42.70(a); CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136, at 81–82.
161 CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136, at 81.
162 Id. at 85 (“[PTAB] receives relatively few requests for presenting live testimony.”).
163 35 U.S.C. § 316(a)(11).
164 Id. § 318(a).
165 Id. § 318(b).
166 Id. § 317.
167 Id. § 317(a).
168 Id. § 6(c); 37 C.F.R. § 42.71(d).
169 See infra “United States v. Arthrex”; “What Roles Do the USPTO Director and PTAB Management Play in PTAB
Decisions?”.
170 35 U.S.C. § 319. While the AIA affords a procedural right to appeal, the appealing party must have Article III
standing under the Constitution to maintain an appeal. See generally Cong. Rsch. Serv., ArtIII.S2.C1.6.1 Overview of
Standing, https://constitution.congress.gov/browse/essay/artIII-S2-C1-6-1/ALDE_00012992/ (last visited Mar. 28,
2024). A patent holder dissatisfied with a PTAB decision will usually have standing to appeal the cancellation of a
patent claim. However, challengers to patents that do not practice the invention (e.g., nonprofit groups) may lack
standing to appeal PTAB decisions upholding the patent. See, e.g., Consumer Watchdog v. Wis. Alumni Rsch. Found.,
753 F.3d 1258, 1262–63 (Fed. Cir. 2014) (holding that nonprofit consumer rights organization lacked standing to
appeal IPR decision affirming patentability).
171 35 U.S.C. § 319.
172 Oil States Energy Servs., LLC v. Greene’s Energy Grp., LLC, 584 U.S. 325, 332–35 (2018).
173 35 U.S.C. § 314(d).
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IPR Statistics
In a typical year, PTAB receives between 1,000 and 2,000 petitions for IPR or PGR.174 Of these
filings, the overwhelming majority are IPRs.175 In FY2023, for example, PTAB received 1,209
IPR petitions (97.6%), compared with 30 PGR petitions (2.4%).176
Litigating an IPR costs several hundreds of thousands of dollars in legal costs on average.177
While expensive, an IPR is usually many times cheaper than litigating a patent suit in the federal
courts, which can cost several million dollars.178
IPR Outcomes
Very roughly, PTAB denies institution—that is, declines to hear the IPR or PGR—in a little less
than one-third of petitions.179 A similar number of cases settle.180 For example, of the 1,327
petitions resolved in FY2023, PTAB denied institution in 374 cases (28%), and 402 cases settled
(30%).181 Thus, PTAB typically reaches a final written decision for between 35–40% of the
petitions it receives.182
In those IPRs and PGRs that do reach a final written decision, PTAB cancels some or all of the
patent claims at issue in the large majority of cases. In FY2023, for example, PTAB issued a final
written decision in 508 cases.183 Of those, it found all the claims unpatentable in 343 cases
(67.5%), upheld all of the patent claims in 87 cases (17.1%), and reached a mixed result (i.e.,
upholding some patent claims and canceling others) in 78 cases (15.4%).184 Figure 1 displays
these outcome statistics as reported by USPTO.

174 PTAB FY23 STATISTICS, supra note 112, at 3 (1,239 post-issuance review petitions received in FY2023); USPTO,
PTAB TRIAL STATISTICS: FY23 END OF YEAR OUTCOME ROUNDUP—IPR, PGR 3 (2022),
https://www.uspto.gov/sites/default/files/documents/ptab__aia_fy2022_roundup.pdf [hereinafter PTAB FY22
Statistics] (1,367 post-issuance review petitions received in FY2022); see also Dani Kass, PTAB Filings Drop
Alongside Declining Patent Litigation, LAW360 (Feb. 7, 2024, 11:02 PM), https://www.law360.com/articles/1794397
(number of annual IPR filings between 2014 and 2023 ranging from a high of 1,723 petitions in 2017 to a low of 1,157
petitions in 2023).
175 See Kass, supra note 174 (showing over 1,000 IPRs filed each year, but only several dozen PGRs).
176 PTAB FY23 STATISTICS, supra note 112, at 3.
177 AIPLA, REPORT OF THE ECONOMIC SURVEY 2019, at 52 (2019), https://ipwatchdog.com/wp-
content/uploads/2021/08/AIPLA-Report-of-the-Economic-Survey-Relevant-Excerpts.pdf (median litigation costs for
IPRs ranging from $100,000 to $350,000 depending on the type of case and amount in controversy).
178 Id. at 50–52 (median total patent litigation costs ranging from $700,000 to $8 million depending on the type of case
and amount in controversy); accord Stephen Yelderman, Prior Art in Inter Partes Review, 104 IOWA L. REV. 2705,
2706 (2019) (“[T]he cost of litigating an IPR to a final written decision was about $324,000, which pales in comparison
to the $1–2 million reported cost of litigating a patent in court.”).
179 See, e.g., PTAB FY23 STATISTICS, supra note 112, at 10 (institution denied for 28% of petitions in FY2023); PTAB
FY22 STATISTICS, supra note 174, at 11 (institution denied for 30% of petitions in FY2022).
180 See, e.g., PTAB FY23 STATISTICS, supra note 112, at 10 (30% of petitions settled in FY2023); PTAB FY22
STATISTICS, supra note 174, at 11 (27% of petitions settled in FY2022).
181 PTAB FY23 STATISTICS, supra note 112, at 10.
182 See, e.g., id. (final written decision in 39% of petitions in FY2023); PTAB FY22 STATISTICS, supra note 174, at 11
(final written decision in 37% of petitions in FY2022).
183 See PTAB FY23 STATISTICS, supra note 112, at 10.
184 See id.
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Figure 1. IPR and PGR Outcomes by Petition in FY2023

Source: USPTO, PTAB TRIAL STATISTICS: FY23 End of Year Outcome Roundup—IPR, PGR 10 (2023),
https://www.uspto.gov/sites/default/files/documents/ptab_aia_fy2023__roundup.pdf.
Notes: “FWD” means final written decision by the Patent Trial and Appeal Board (PTAB). “IPR” refers to inter
partes review; “PGR” refers to post-grant review.
Some critics of PTAB argue that because PTAB cancels at least one patent claim in over 80% of
its final written decisions, the panels may be biased against patent owners.185 While that number
is accurate, PTAB denies institution in nearly one-third of IPRs filed. Since a denial of institution
leaves the patent claims intact, it arguably represents a “win” for the patent holder.186 Moreover,
because PTAB may institute an IPR only if it finds that “there is a reasonable likelihood that the
petitioner would prevail with respect to at least 1 of the claims challenged,”187 it is perhaps not
surprising that most of the instituted IPRs in fact invalidate one or more claims.188

185 See Steve Brachmann & Gene Quinn, Are More than 90 percent of Patents Challenged at the PTAB Defective?,
IPWATCHDOG (June 14, 2017, 10:00 AM), https://ipwatchdog.com/2017/06/14/90-percent-patents-challenged-ptab-
defective/id=84343/ (arguing that the statistics suggest that either “PTAB APJs are being too aggressive in invalidating
patents or that the examiners are producing incredibly poor quality patents”).
186 See Angela Morris, US PTAB Invalidation Rates Under the Microscope as Reform Bill Refiled, IAM (June 26,
2023), https://www.iam-media.com/article/us-ptab-invalidation-rates-under-the-microscope-reform-bill-refiled (“The
petitions that were denied institution should be viewed as a patent holder win.”). Counted in that way, one could argue
that the patent holder “wins” (374 denials and 87 written decisions upholding all claims) about as often as they “lose”
(343 written decisions finding all claims unpatentable and 78 finding some claims unpatentable). Some argue that
settlements should be also counted as losses for the patent holder, however. See Brachmann & Quinn, supra note 185
(arguing that “many (if not all) of these [IPR] settlements result in outcomes unfavorable to the patent owner”).
Ultimately, how to characterize these various outcomes is a matter of interpretation.
187 35 U.S.C. § 314(a).
188 See Brachmann & Quinn, supra note 185 (“If [PTAB] judges are doing a really good job on institution, one should
expect to see that most of the decisions instituted reach a fairly favorable petitioner outcome.” (quoting Brian
Howard)).
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When appealed to the Federal Circuit, the large majority of PTAB findings on patent validity or
invalidity are affirmed.189 One study found an affirmance rate for IPRs of over 90%.190 While
district court patent validity findings are also usually affirmed by the Federal Circuit, the
affirmance rate (85%) is somewhat lower.191 Notably, the Federal Circuit reverses district courts
on patent validity issues at a higher rate (12.1% reversal rate) than it does PTAB decisions (4.8%
reversal rate).192

189 Matthew G. Sipe, Experts, Generalists, Laypeople—and the Federal Circuit, 32 HARV. J.L. & TECH. 575, 578
(2019).
190 Id. at 604 tbl.7.
191 Id. at 610 tbl.15.
192 See id. (“Three tendencies emerge from this picture: (1) the PTAB is affirmed notably more often than district courts
on validity issues; (2) district court decisions tend to be reversed outright, rather than vacated or remanded; and (3)
PTAB decisions, on the other hand, experience both types of non-affirmance in roughly equal measure.”).
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“Big Tech” and IPRs
Some observers allege that large technology companies lobbied for the creation of PTAB and are its primary
beneficiaries.193 As evidence, critics note that some so-called “big tech” firms are among the most frequent users
of IPRs. According to one analysis, in 2021, Samsung, Apple, Google, Intel, and Microsoft collectively accounted for
81% of PTAB petitions filed by the top 10 petitioners during that year.194 Critics allege that such companies are
using PTAB as “a key tool in their predatory infringement strategies.”195
Large technology firms are also among the most frequent defendants in patent litigation.196 Some stakeholders
claim that financial incentives may lead these companies to infringe patents more often than smaller firms.197 This
view holds that well-resourced firms may choose to engage in a practice called efficient infringement, in which a firm
intentionally infringes a patent rather than purchasing or licensing it, based on the calculation that potential profits
outweigh the potential costs associated with legal fees or damages it may owe as a result of infringement.198
Some observers argue that the practice of efficient infringement has been encouraged by recent legal changes,
which have made obtaining injunctive relief for patent infringement (i.e., a court order stopping the defendant’s
infringing activities) more difficult to obtain.199 They claim that when injunctive relief is not granted and adequate
damages are not awarded to patent owners whose rights have been infringed, potential infringers may decide that
the economic benefits of infringement outweigh the potential costs of being sued for patent infringement.200
Others argue that large technology firms are frequently sued not because they are more likely to infringe patents
but because they are attractive targets of abusive litigation practices. Such practices, they claim, often involve so-
called “patent trolls”201 asserting low quality patents that should not have been granted by USPTO.202 For
example, in 2022, Google’s general counsel argued the declining quality of U.S. patents was causing an uptick in
abusive patent litigation and accused patent trolls and opportunistic companies of weaponizing such patents against
their rivals.203

193 See Adam Mossoff, Big Tech’s Abuse of Patent Owners in the PTAB Must End, HERITAGE FOUNDATION 5–6 (June
29, 2023), https://www.heritage.org/sites/default/files/2023-06/LM336.pdf; Paul R. Michel, Big Tech Has a Patent
Violation Problem, HARVARD BUSINESS REVIEW (Aug. 5, 2023), https://hbr.org/2022/08/big-tech-has-a-patent-
violation-problem.
194 Paul Michel & Chris Israel, Don’t Let Big Tech Sabotage U.S. Innovators’ Protections, BLOOMBERG LAW (Apr. 22,
2022) (companies listed in the order they appear in the article).
195 Mossoff, supra note 193, at 5–6; see Michel, supra note 193.
196 See Figure 11 in UNIFIED PATENTS, 2022 Patent Dispute Report (Jan. 5, 2023),
https://www.unifiedpatents.com/insights/2023/1/4/2022-patent-dispute-report (identifying Alphabet, Amazon, Apple,
AT&T, Cisco, Lenovo, Microsoft, Samsung, Verizon, and Walmart as the most frequently named defendants in patent
infringement suits in U.S. federal courts in 2022).
197 See Michel, supra note 193.
198 See Julie Turner, The Nonmanufacturing Patent Owner: Toward a Theory of Efficient Infringement, 86 CAL. L. REV.
179, 210 (1998).
199 See Kristen Osenga, “Efficient” Infringement and Other Lies, 52 SETON HALL L. REV. 1085 (2022); Adam Mossoff,
Institutional Design in Patent Law: Private Property Rights or Regulatory Entitlements, 92 S. CAL. L. REV. 921 (2019).
In the 2006 case eBay v. MercExchange, the Supreme Court held that an equitable balancing test governed the decision
of whether a district court should issue a permanent injunction in patent infringement cases, reversing the Federal
Circuit rule that injunctions should issue “absent exceptional circumstances.” 547 U.S. 388 (2006).
200 See Mossoff, supra note 199, at 939. According to one commentator, when injunctive relief is not routinely granted,
“it makes much more sense for a potential infringer to infringe now—and pay later. At worst, if an injunction is not
granted following a patent infringement trial, the infringer will simply have to pay damages for past infringement and
an ongoing royalty for continued, future infringement. This result is akin to having taken a license to start with, but
with the bonus of an interest-free loan for the period of infringement prior to and during the trial period.” Osenga,
supra note 199, at 1087.
201 “Patent troll” is a pejorative term for patent plaintiffs that enforce patents but do not manufacture or sell products.
FTC, supra note 9, at 15–17. According to an opinion from the Supreme Court, “Trolls, in the patois of the patent
community, are entities that hold patents for the primary purpose of enforcing them against alleged infringers, often
exacting outsized licensing fees on threat of litigation.” Halo Elecs., Inc. v. Pulse Elecs., Inc. 579 U.S. 93, 109 (2016).
202 Patent quality generally refers to whether granted patents actually meet the statutory standards of patentability.
These include requirements that the invention claimed in a patent be novel, nonobvious, and clearly described.
(continued...)
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Post-Grant Review
In addition to IPR, the AIA created PGR, another administrative proceeding that can result in
cancellation of an issued patent.204 There are three primary differences between PGR and IPR.
First, a petition for PGR may be filed only during the first nine months after a patent issues.205 An
IPR petition, by contrast, may be filed only after the window for filing PGR ends; that is, an IPR
must be filed more than nine months after the patent issues (and after any PGR regarding the
patent concludes).206 Second, the standard for instituting a PGR is higher, requiring PTAB to find
“that it is more likely than not that at least 1 of the claims challenged in the petition is
unpatentable.”207 By contrast, institution of IPR requires only “a reasonable likelihood that the
petitioner would prevail with respect to at least 1 of the claims challenged in the petition.”208
The third main difference between PGR and IPR concerns the grounds for cancellation that may
be presented to PTAB. While an IPR may challenge a patent claim only on grounds of
anticipation (35 U.S.C. § 102) or obviousness (35 U.S.C. § 103) based on prior art patents or
printed publications (and not other forms of prior art, such as public uses),209 a PGR may
challenge whether a patent claim meets any of the requirements for validity in the Patent Act.210
For example, a PGR petitioner may argue that the patent is not directed to patentable subject
matter under 35 U.S.C. § 101 or that the claims are indefinite under 35 U.S.C. § 112—arguments
that are not available in IPR.
Procedurally, PGR functions similarly to IPR. Anyone other than the patent holder may file a
petition with USPTO requesting that PTAB initiate PGR to review the validity of the patent.211
After a PGR petition is filed, the patent owner may file a preliminary response arguing that the
patent claims meet all patenting requirements.212 Based on the petition and any response, the
USPTO Director determines whether “it is more likely than not that at least 1 of the claims
challenged in the petition is unpatentable.”213 If so, PTAB may institute review.214 PTAB may also
institute review if the petition “raises a novel or unsettled legal question that is important to other
patents or patent applications.”215 As with IPRs, the decision whether to institute a PGR is
unreviewable.

203 Halimah DeLaine Prado, Reforming the Patent System to Support American Innovation, GOOGLE: THE KEYWORD,
(Apr. 28, 2022), https://blog.google/outreach-initiatives/public-policy/reforming-the-patent-system-to-support-
american-innovation/.
204 35 U.S.C. §§ 321–329.
205 Id. § 321(c).
206 Id. § 311(c).
207 Id. § 324(a).
208 Id. § 314(a).
209 Id. § 311(b).
210 Id. § 321(b).
211 Id. § 321(a).
212 Id. § 323.
213 Id. § 324(a). The USPTO Director has delegated this authority to PTAB. 37 C.F.R. § 42.4 (“[PTAB] institutes the
trial on behalf of the Director.”); Thryv, Inc. v. Click-to-Call Techs., LP, 590 U.S. 45, 49 (2020) (“The Director has
delegated institution authority to the Patent Trial and Appeal Board.”).
214 35 U.S.C. § 324(a). Notably, the decision whether to institute is permissive, rather than mandatory. See id. (stating
that “the director may not authorize” PGR “unless” the petitioner demonstrates that it is more likely than not that at
least one claim is unpatentable, but not mandating institution (emphasis added)).
215 Id. § 324(b).
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If PTAB institutes review, the patent owner may file a full response to the petition; the petitioner
may file a reply; and, generally, the patent owner may file a sur-reply.216 The patent owner may
also file a motion to amend the claims.217 Following the sur-reply, PTAB holds a hearing where
the petitioner and patent owner present arguments regarding whether the patent meets the relevant
requirements for patenting.218 Following the hearing, PTAB issues a final written decision
determining whether the patent claims are valid.219 A party dissatisfied with the final written
decision may seek review by the USPTO Director220 or appeal to the Federal Circuit.221 If, after
all appeals, the patent claims are held invalid, USPTO issues a certificate cancelling those
claims.222
Covered Business Method Review
The AIA also introduced CBM review, a time-limited administrative proceeding for reviewing
patents relating to methods of doing business.223 CBM review followed many of the same
procedures as PGR,224 with several differences. A CBM review petition could be filed only by a
party who “has been sued for infringement of the patent or has been charged with infringement
under that patent” and only against a patent that is the subject of the suit.225 Moreover, the patent
had to claim a “covered business method,” which the statute defined as “a method or
corresponding apparatus for performing data processing or other operations used in the practice,
administration, or management of a financial product or service, except that the term [did] not
include patents for technological inventions.”226 The CBM review program sunsetted on
September 16, 2020.227
Comparison of PTAB and Other Post-Grant Proceedings
Table 1 compares filing deadlines, standing, grounds for invalidation, and evidentiary thresholds
for the three types of post-grant proceedings established by the AIA—PGR, IPR, and CBM
review—as well as ex parte reexaminations, which predate the AIA and are not administered by
PTAB.

216 See CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136; see also 35 U.S.C. § 326(a) (giving USPTO Director
the power to promulgate regulations governing PGR).
217 35 U.S.C. § 326(a)(9).
218 See id. § 326(a)(10).
219 Id. § 328(a).
220 See infra “Interim Director Review Process.”
221 35 U.S.C. § 329.
222 Id. § 328(b).
223 Leahy-Smith America Invents Act, Pub. L. No. 112-29, 125 Stat. 331, § 18(a) (2011).
224 Id. § 18(a)(1)(A).
225 Id. § 18(a)(1)(B).
226 Id. § 18(d)(1).
227 Id. § 18(a)(3).
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Table 1. USPTO Post-Grant Proceedings
Time for
Challenger
Evidentiary
Sunset
Proceeding
Filing
(Standing)
Grounds
Threshold
Date
Ex Parte
Any time.
Anyone,
Novelty or
Substantial new
None.
Reexamination
including the
nonobviousness on
question of
(not PTAB-
USPTO
the basis of patents or patentability.
administered)
Director on
printed publications.
his/her own
initiative.
PGR
No later than
Anyone except Patent-eligible subject
More likely than
None.
nine months
the patent
matter; novelty;
not that at least
after issuance
owner.
nonobviousness;
one of the
or reissuance
indefiniteness; written
challenged patent
of a patent.
description;
claims is
enablement.
unpatentable.
IPR
No earlier than Anyone except Novelty or
Reasonable
None.
(1) nine
the patent
nonobviousness on
likelihood that the
months after
owner.
the basis of patents or petitioner would
patent grant or
printed publications.
prevail with
(2) after the
respect to at least
termination of
one of the
any PGR.
challenged claims.
CBM Review
Any time
A person or
May challenge only a
More likely than
Sept.
before the
the person’s
covered business
not that at least
16,
sunset date.
real party in
method patent.
one of the
2020.
interest or
May raise patent-
challenged claims
privy who has
eligible subject
is unpatentable.
been sued or
matter; novelty;
charged with
nonobviousness;
infringement
indefiniteness; written
under the
description; or
challenged
enablement issues.
patent.
Source: Created by CRS based on Title 35 chapters 30 (ex parte reexamination), 31 (IPR), and 32 (PGR), and
Public Law No. 112-29, 125 Stat. 331, section 18 (CBM review).
Notes: “PTAB” means the Patent Trial and Appeal Board; “PGR” means post-grant review; “IPR” means inter
partes review; “CBM” means covered business method.
PTAB at the Supreme Court
Starting in 2016, the Supreme Court decided six major cases involving PTAB in a five-year
period.228 The Court’s interest in PTAB may reflect, to some degree, novel statutory and
constitutional issues raised by the AIA, as well as PTAB’s importance in the patent system. This
section surveys the facts and holdings of each of these cases.

228 See Cuozzo Speed Techs., LLC v. Lee, 579 U.S. 261 (2016); SAS Inst., Inc. v. Iancu, 138 S. Ct. 1348 (2018); Oil
States Energy Servs., LLC v. Greene's Energy Grp., LLC, 584 U.S. 325 (2018); Return Mail, Inc. v. U.S. Postal Serv.,
139 S. Ct. 1853 (2019); Thryv, Inc. v. Click-to-Call Techs., LP, 590 U.S. 45 (2020); United States v. Arthrex, Inc., 594
U.S. 1 (2021).
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Statutory Interpretation Cases
Four of the six Supreme Court cases addressing PTAB have raised questions regarding the correct
interpretation of provisions of the AIA, including whether the AIA gives PTAB authority to select
a certain legal standard for claim construction in AIA proceedings (yes), whether the AIA allows
PTAB to institute an IPR for only some of the patent claims challenged in a petition (no), and
whether the federal government is a “person” that may file a petition for IPR (no).
In addition, two of these cases addressed the proper interpretation of 35 U.S.C. § 314(d), an AIA
provision stating that the decision whether or not to institute an IPR is “final and
nonappealable.”229 As discussed below, the Supreme Court held that PTAB’s decision to institute
an IPR cannot be appealed on grounds that the petition did not comply with the AIA’s
requirements or was untimely.
Cuozzo Speed Technologies, LLC v. Lee
The first Supreme Court decision to address IPR, 2016’s Cuozzo Speed Technologies, LLC v. Lee,
involved two separate issues: (1) the scope of Section 314(d)’s no-appeal provision and (2)
whether the AIA authorized USPTO to issue a regulation adopting a “broadest reasonable
construction” (BRC) standard for claim construction in IPR proceedings.230 The Court concluded
that PTAB’s institution decision was nonappealable and that USPTO had authority to issue the
BRC regulation,231 affirming the Federal Circuit’s decision below.232
Nonappealability of Institution Decisions. Regarding the no-appeal provision, Cuozzo, a patent
owner, argued that PTAB had improperly instituted an IPR because it invalidated certain of its
patent claims on bases only implicitly raised in the petition.233 Thus, Cuozzo argued, the petition
had not identified the challenged claims or grounds “with particularity” as required by 35 U.S.C.
§ 312(a)(3).234
The Supreme Court held that the no-appeal provision rendered PTAB’s decision to institute
nonappealable.235 While the Supreme Court recognized a “‘strong presumption’ in favor of
judicial review” that could only “be overcome by ‘clear and convincing’ indications” from
Congress, it held that the language in Section 314(d) met that standard.236 To hold otherwise, the
Court reasoned, would undercut the congressional objective of allowing USPTO to revisit
patentability determinations.237 Specifically, the Court doubted that Congress would have given
USPTO these review powers if it “thought that the agency’s final decision could be unwound
under some minor statutory technicality related to its preliminary decision to institute [an
IPR].”238
Nevertheless, the Supreme Court indicated that Section 314(d)’s scope is not boundless. The
Court cautioned that the no-appeal provision “applies where the grounds for attacking the

229 35 U.S.C. § 314(d).
230 Cuozzo, 579 U.S. at 265–66.
231 See id. at 266.
232 See id. at 283.
233 See id. at 270.
234 See id.
235 See id. at 271.
236 Id. at 273–74 (quoting Block v. Cmty. Nutrition Inst., 467 U.S. 340, 349–50 (1984)).
237 See id. at 272.
238 Id.
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decision to institute [an IPR] consist of questions that are closely tied to the application and
interpretation of statutes related to the Patent Office’s decision to initiate [IPR].”239 Thus, for
instance, Section 314(d) bars judicial review where a patent holder challenges PTAB’s
determination that the petition shows a “reasonable likelihood” of success.240
By contrast, the Court stated that it was not deciding whether the no-appeal provision would
apply to “appeals that implicate constitutional questions, that depend on other less closely related
statutes, or that present other questions of interpretation that reach, in terms of scope and impact,
well beyond ‘this section.’”241 The Court also indicated that “shenanigans” where PTAB acted
beyond its statutory jurisdiction would be reviewable.242 (As explained below, the Court would
revisit the scope of Section 314(d)’s scope four years later, in Thryv, Inc. v. Click-To-Call
Technologies, LP.243)
Justice Alito, dissenting in part and joined by Justice Sotomayor, argued that Section 314(d) did
not overcome the presumption against judicial review.244 Justice Alito argued that Section 314(d)
should be read solely as precluding a party from appealing directly from the institution decision
itself, while permitting a party to seek judicial review of the institution decision after PTAB
issues its final written decision in the IPR.245
USPTO Authority for the BRC Claim Construction Standard. Turning to claim construction,
the Court held that the AIA’s provision giving USPTO authority to issue regulations “establishing
and governing [IPR]” allowed it to issue a regulation adopting the BRC standard.246 Since the
AIA did not specify the claim construction standard to be used in IPR, the Court held that, as a
matter of Chevron deference, USPTO was permitted to adopt reasonable rules to fill that statutory
“gap.”247 The Court concluded that adopting the BRC standard was reasonable, explaining that
USPTO has used this standard in other contexts for many years and that this standard protects the
public by helping prevent patentees from “tying up too much knowledge.”248 The Court rejected
Cuozzo’s argument that PTAB was required to use the same claim construction standard used by
district courts, noting that IPR is “more like a specialized agency proceeding” than a judicial
proceeding in some respects and is meant to serve a public interest in keeping “‘patent
monopolies . . . within their legitimate scope.’”249
In a concurring opinion, Justice Thomas argued that Chevron deference was unnecessary to
resolve the BRC question, since the AIA “contains an express and clear conferral of authority to
the Patent Office to promulgate rules governing its own proceedings,” and the rule adopting the
BRC standard was not “‘arbitrary, capricious, an abuse of discretion, or otherwise not in
accordance with law’” under the Administrative Procedure Act.250

239 Id. at 274–75.
240 Id. (citing 35 U.S.C. § 314(a)).
241 Id. at 275.
242 Id.
243 590 U.S. 45 (2020).
244 Cuozzo, 579 U.S. at 387 (Alito, J., concurring in part and dissenting in part).
245 See id. at 291.
246 Id. at 276 (quoting 35 U.S.C. § 316(a)(4)).
247 Id. at 276–77 (citing Chevron U.S.A. Inc. v. Nat. Res. Def. Council, Inc., 467 U.S. 837 (1984)).
248 See id. at 281.
249 Id. at 278–80 (quoting Precision Instrument Mfg. Co. v. Auto. Maint. Mach. Co., 324 U.S. 806, 816 (1945)).
250 Id. at 286–87 (Thomas, J., concurring) (quoting 5 U.S.C. § 706(2)(A)).
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SAS Institute, Inc. v. Iancu
In the 2018 decision SAS Institute, Inc. v. Iancu,251 the Supreme Court held that the AIA did not
permit a PTAB practice called “partial institution,” whereby PTAB could institute an IPR for
some but not all patent claims challenged in a petition.252 Under the holding in SAS, PTAB must
follow an all-or-nothing approach to institution decisions, either denying institution entirely or
instituting an IPR on all of the claims the petitioner challenged.253 In other words, PTAB may not
selectively “weed out” challenges to certain claims at the institution stage.
The case began when SAS petitioned PTAB to institute an IPR on all 16 claims of another
company’s software patent.254 Based on a USPTO regulation allowing “partial institution,” PTAB
instituted an IPR as to nine of those claims, ultimately finding eight of them unpatentable.255 On
appeal to the Federal Circuit, SAS argued that the AIA required PTAB to decide the patentability
of all of the claims challenged in the petition once it instituted an IPR, but the Federal Circuit
rejected this argument.256
The Supreme Court’s opinion, by Justice Gorsuch, held that the plain text of 35 U.S.C. § 318(a)
prohibited partial institution.257 Section 318(a) provides: “If an [IPR] is instituted and not
dismissed under this chapter, the [PTAB] shall issue a final written decision with respect to the
patentability of any patent claim challenged by the petitioner.”258 The Court held that “any” in this
context implies “every,” requiring PTAB to resolve the patentability of every claim challenged in
the petition if it decides to institute an IPR.259 The Court reasoned that other statutory features
supported this reading of Section 318(a), including the fact that the AIA does not permit PTAB to
institute an IPR of its own initiative and that IPR utilizes a “party-directed, adversarial
process.”260 Further, the Court held that Section 318(a) is unambiguous, foreclosing any possible
deference to PTAB’s interpretation of the statute.261 In short, the Court held, while PTAB
generally has discretion “whether to institute review” if the petitioner shows a reasonable
likelihood of success on at least one patent claim, PTAB does not have discretion “regarding what
claim that review will encompass.”262
Four Justices dissented from the Court’s opinion. Justice Ginsburg authored one dissenting
opinion, arguing that the Court’s holding would needlessly waste PTAB’s resources.263 Justice
Ginsburg reasoned that, since PTAB is never required to institute an IPR, PTAB could accomplish
the same result as partial institution—albeit less efficiently—by denying institution and
encouraging the petitioner to file a new petition challenging only a subset of the same claims.264

251 138 S. Ct. 1348 (2018).
252 See id. at 1354.
253 See id. at 1353.
254 See id. at 1354.
255 See id.
256 See id.
257 See id.
258 35 U.S.C. § 318(a).
259 See SAS, 138 S. Ct. at 1354.
260 Id. at 1355.
261 See id. at 1358 (discussing Chevron U.S.A. Inc. v. Nat. Res. Def. Council, Inc., 467 U.S. 837 (1984)).
262 Id. at 1356.
263 Id. at 1360 (Ginsburg, J., dissenting).
264 See id.
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In a second dissenting opinion, Justice Breyer argued that Section 318(a) is ambiguous, requiring
the Court to defer to PTAB’s reasonable interpretation of the statute under Chevron.265 Justice
Breyer reasoned that the phrase “any patent claim challenged by the petitioner” could refer either
to challenges made in the petition or to challenges that remain once the IPR instituted.266 Justice
Breyer further contended that PTAB’s resolution of this ambiguity, allowing “partial institution,”
was reasonable and entitled to deference.267
Return Mail, Inc. v. U.S. Postal Service
In 2019, the Supreme Court decided Return Mail, Inc. v. U.S. Postal Service,268 holding that the
AIA does not permit governmental entities to petition for AIA proceedings (i.e., IPR, PGR, or
CBM review).269 This holding has significance for scenarios in which the government—or certain
private parties acting on the government’s behalf, such as government contractors—might be
accused of patent infringement.
Return Mail, Inc. owned a patent on a method for processing undeliverable mail.270 Asserting that
the U.S. Postal Service infringed this patent, Return Mail sued the Postal Service in the U.S.
Court of Federal Claims under 28 U.S.C. § 1498.271 Section 1498 allows a patent owner to sue the
United States in the Court of Federal Claims when the patented invention “is used or
manufactured by or for the United States without license of the owner thereof or lawful right to
use or manufacture the same.”272 Section 1498 allows a patent owner—such as Return Mail—to
recover the “reasonable and entire compensation for such use and manufacture,” as well as costs
and attorneys’ fees in some cases.273
In response to Return Mail’s pre-suit infringement accusations, the Postal Service petitioned
USPTO for ex parte reexamination of the asserted patent.274 USPTO conducted an ex parte
reexamination and confirmed the validity of the patent (albeit by substituting claims).275 Then,
after Return Mail had filed its infringement suit in the Court of Federal Claims, the Postal Service
petitioned for CBM review of the patent.276 PTAB initiated a CBM review and ruled that the

265 Id. (Breyer, J., dissenting) (citing Chevron, 467 U.S. at 842–43).
266 Id. at 1361 (Breyer, J., dissenting).
267 See id. at 264.
268 139 S. Ct. 1853 (2019).
269 See id. at 1867.
270 See id. at 1861.
271 See id.
272 28 U.S.C. § 1498(a).
273 Id. (permitting award of costs and fees “if the owner is an independent inventor, a nonprofit organization, or an
entity that had no more than 500 employees at any time during the 5-year period preceding the use or manufacture”).
Section 1498 provides that patent owners may bring such claims against the United States not only when the
government itself uses or manufactures the invention, but also when private parties use or manufacture the invention
“for” the government with its “authorization or consent.” Id. (“[T]he use or manufacture of an invention described in
and covered by a patent of the United States by a contractor, a subcontractor, or any person, firm, or corporation for the
Government and with the authorization or consent of the Government, shall be construed as use or manufacture for the
United States.”).
274 See Return Mail, 139 S. Ct. at 1861.
275 See id.
276 See id.
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patent was invalid because it was directed to ineligible subject matter. On appeal, the Federal
Circuit affirmed PTAB’s decision.277
At the Supreme Court, Return Mail hinged on whether, as a matter of statutory interpretation, the
government is a “person” eligible to petition for CBM review or other AIA proceedings.278 The
AIA allows “a person who is not the owner of a patent” to petition for IPR, PGR, and CBM
review,279 but it does not define the word “person.”280
The Court, in an opinion by Justice Sotomayor, held that “person” as used in the AIA does not
include the government and its agencies.281 To reach this holding, the Court applied a
“longstanding interpretive presumption” that the word “person” does not include the
government.282 The Court noted that Congress itself had adopted this presumption283 in a 1947
law (the Dictionary Act) providing that specific words, as used in acts of Congress, should be
interpreted according to definitions provided in the Dictionary Act “unless the context indicates
otherwise.”284 The Dictionary Act’s definition of a “person,” the Court noted, included certain
corporate entities but not the government.285
The Court rejected the Postal Service’s argument that Congress must have intended the
government to be able to petition for AIA proceedings since Congress has made the government
liable to pay compensation for patent infringement under Section 1498.286 In response to this
argument, the Court noted that the government’s potential liability under Section 1498 is less
severe than that of ordinary infringers in a civil suit, and the government may still assert
invalidity as a defense in any Section 1498 lawsuit and petition for non-AIA proceedings such as
ex parte reexamination.287
Justice Breyer issued a dissenting opinion that was joined by Justices Ginsburg and Kagan.288 The
dissent argued that the presumption against interpreting “person” in the AIA to include the
government was weakened by the fact that certain other uses of “person” in the Patent Act (e.g.,
those referring to eligibility to obtain a patent) include the government.289 The dissent also argued
that allowing the government to petition for AIA proceedings would better serve Congress’s
purpose in enacting the AIA and that it would be anomalous for Congress not to allow the

277 See id.
278 See id.
279 Id. at 1860; see 35 U.S.C. §§ 311(a) (IPR), 321(a) (PGR); Pub. L. No. 112-29 § 18(a)(1), (B), 125 Stat. 330 (2011)
(providing that CBM review “shall be regarded as, and shall employ the standards and procedures of, a [PGR]” and that
“[a] person may not file a petition for [CBM review] unless the person or the person’s real party in interest or privy has
been sued . . . or . . . charged with infringement”).
280 See Return Mail, 139 S. Ct. at 1861.
281 See id. at 1867.
282 Id. at 1862–63 (quoting Vt. Agency of Nat. Res. v. United States ex rel. Stevens, 529 U.S. 765, 780–81 (2000)).
283 See Return Mail, 139 S. Ct. at 1863.
284 1 U.S.C. § 1.
285 See id. (“[T]he words ‘person’ and ‘whoever’ include corporations, companies, associations, firms, partnerships,
societies, and joint stock companies, as well as individuals . . . .”).
286 See Return Mail, 139 S. Ct. at 1866–67.
287 See id.
288 See id. at 1868–72 (Breyer, J., dissenting).
289 See id. at 1868–70.
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government to petition for AIA review while allowing the government to be sued for patent
infringement and to avail itself of other USPTO invalidity proceedings.290
Thryv, Inc. v. Click-to-Call Technologies, LP
In 2020, the Supreme Court again considered Section 314(d)’s no-appeal provision in Thryv, Inc.
v. Click-to-Call Technologies, LP.291 Click-to-Call concerned the “time-bar” provision of 35
U.S.C. § 315(b), which requires petitioners to file an IPR no more one year after they are sued for
infringement of the patent.292 The Court, in an opinion by Justice Ginsburg, held that
Section 314(d) bars judicial review of PTAB determinations regarding Section 315(b)’s time
bar.293
The respondent, Click-to-Call Technologies, LP, owned a patent that Thryv, Inc. challenged via an
IPR petition filed in 2013.294 Click-to-Call claimed the petition was untimely, arguing that
Section 315(b)’s one-year clock had begun to run in 2001, when Thryv’s predecessor was sued
for infringement of the patent.295 PTAB, however, ruled that this infringement suit did not trigger
the one-year clock because it had been dismissed without prejudice.296
The Court found Cuozzo’s holding—that Section 314(d) bars review of “matters ‘closely tied to
the application and interpretation of statutes related to’ the institution decision”—controlling in
Thryv, since the Section 315(b) time bar is an “integral” condition on institution.297 The Court
also determined that the “purpose and design” of the statute creating IPR reinforces the
conclusion that the no-appeal provision applies to the time bar because IPR “sought to weed out
bad patent claims,” and that allowing review of the time bar would permit the continued
enforcement of patents held to be invalid.298
The Court rejected Click-to-Call’s arguments that Section 314(d) does not apply to time-bar
determinations, including its attempt to read Section 314(d) as limited to the initial merits
determination.299 The Court found this argument foreclosed by Cuozzo and inconsistent with
related no-appeal provisions that Congress drew more narrowly. If Congress had intended
Section 314(d)’s scope to be narrower, the Court reasoned, it would have used narrower
language.300 Accordingly, the Court vacated and remanded the Federal Circuit’s judgment, with
instructions to dismiss the appeal for lack of jurisdiction.301
Justice Gorsuch issued a dissenting opinion that Justice Sotomayor joined in part. Justice Gorsuch
argued that Section 314(d)’s text indicates that the no-appeal provision applies only to PTAB’s
initial determination on the merits of the petition, not to other determinations.302 Justice Gorsuch
contended that Cuozzo’s statement to the contrary was “dicta” (i.e., nonbinding language not

290 See id. at 1870–71.
291 590 U.S. 45 (2020).
292 See id. at 47–49.
293 See id.
294 See id.
295 See id. & n. 4.
296 See id. at 47–49.
297 Id. at 46 (quoting Cuozzo, 579 U.S. at 273–75).
298 See id. at 52–54.
299 See id. at 56–57.
300 See id. at 56–59.
301 See id. at 60–61.
302 See id. at 65–66 (Gorsuch, J., dissenting).
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necessary to the holding of that case) and should not control the present case.303 Moreover, he
argued that the presumption of judicial review indicates that the no-appeal provision should be
read narrowly to reach only the initial merits determination.304 Justice Gorsuch also opined that
the Court’s precedents interpreting the AIA shifted too much power to USPTO at the expense of
the courts, particularly considering that the USPTO Director is a political appointee.305 Finally, he
criticized the Court’s previous decision upholding the IPR’s constitutionality as part of a trend of
“handing over judicial powers involving the disposition of individual rights to executive agency
officials.”306
Constitutional Challenges to IPR
While the foregoing cases addressed questions of statutory interpretation of the AIA, the Supreme
Court has also heard two cases challenging aspects of IPR proceedings on constitutional grounds.
In the first of these cases, the Supreme Court upheld the constitutionality of IPR against
arguments that it violates separation-of-powers principles and the constitutional guarantee of jury
trials. In the second case, the Supreme Court invalidated a provision of the AIA that prevented the
USPTO Director from reviewing IPR decisions, holding that it violated the Constitution’s
Appointments Clause.
Oil States Energy Services, LLC v. Greene’s Energy Group, LLC
In Oil States Energy Services, LLC v. Greene’s Energy Group, LLC,307 the Court addressed
whether IPR violates Article III or the Seventh Amendment of the Constitution. In Oil States, a
party whose patent claims had been invalidated in IPR argued that IPR was unconstitutional
because patent rights can be revoked only by an Article III court (e.g., a federal district court),
with the right to a jury trial pursuant to the Seventh Amendment.308 The Supreme Court rejected
this argument.309
The Supreme Court explained that, while Article III “vests the judicial power of the United
States” in federal courts, proceedings that adjudicate “public rights” do not necessarily involve an
exercise of judicial power.310 This “public rights doctrine” gives Congress “significant latitude” to
allow tribunals other than Article III courts to adjudicate public rights.33 The Court held that
patent rights are public rather than private rights, since patents are created pursuant to statute and
give the owner a “public franchise” or monopoly that prevents the public from practicing the
claimed invention.311 Since IPR is “simply a reconsideration” of the initial granting of that public
right312—and since patent claims are granted subject to the possibility that they may be
invalidated in IPR313—the Court held that an issued patent’s validity can constitutionally be

303 See id. at 75–77.
304 See id. at 70–72.
305 See id. at 79–81.
306 Id. at 77–79; see infra “Oil States Energy Services, LLC v. Greene’s Energy Group, LLC.”
307 584 U.S. 325 (2018).
308 See id. at 332–34. PTAB is an administrative or legislative court, not an Article III court, because PTAB hears cases
in which the petitioner lacks standing and APJs do not enjoy protections afforded to Article III judges such as lifetime
tenure. See generally CRS Report R43746, Congressional Power to Create Federal Courts: A Legal Overview (2015).
309 Oil States, 584 U.S. at 344–45.
310 See id. at 332–35.
311 Id. at 334–38.
312 Id. at 334–35.
313 See id. at 335–37.
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determined by PTAB rather than an Article III court. Further, since Congress was permitted to
assign IPR proceedings to non-Article III tribunal, the Court held that appellants had no right to a
trial by jury under the Seventh Amendment.314
Seven Justices joined Justice Thomas’s majority opinion in full, with three of those Justices
concurring to express their perspective that private rights may also sometimes be adjudicated by
bodies other than Article III courts.315 Justice Gorsuch, joined by Chief Justice Roberts,
dissented.316 Justice Gorsuch argued that, based on historical practice in the United States and
England, cancelling an issued patent is an exercise of “judicial power”317 that is not comparable
to USPTO’s initial decision whether to grant a patent.318 Whereas the majority noted that, prior to
the creation of PTAB and IPR, Congress had established other non-Article III proceedings to
cancel issued patents since 1980,319 Justice Gorsuch stressed that such proceedings did not exist
from 1790 (when Congress enacted the first Patent Act) to 1980.320
United States v. Arthrex
In the 2021 case United States v. Arthrex,321 the Supreme Court invalidated the provision of the
AIA that prevented the USPTO Director from reviewing APJs’ IPR decisions, holding that this
provision violated the Constitution’s Appointments Clause.322 The Court’s decision in Arthrex
prompted PTAB to develop an interim process for the Director to review panel decisions—a
process discussed in the following section of this report.
The Appointments Clause sets forth how “Officers of the United States,” such as APJs, may be
appointed.323 It gives Congress discretion to vest the appointment of “inferior [o]fficers” either in
“the President alone, in the Courts of Law, or in the Heads of Departments” but requires the
President to appoint all other officers—whom the Supreme Court refers to as principal officers—
with the Senate’s advice and consent.324 In Arthrex, a company whose patent had been invalidated
in an IPR claimed that APJs’ appointment by the Secretary of Commerce was unconstitutional,
arguing that APJs were principal officers requiring presidential appointment and Senate
confirmation.325
The Supreme Court, in an opinion by Chief Justice Roberts, held that the AIA gave APJs
authority that was “incompatible with their appointment by the Secretary to an inferior office.”326

314 See id. at 334–38.
315 See id. at 334–38 (Breyer, J., concurring).
316 Id. at 345–47 (Gorsuch, J., dissenting).
317 See id. at 347–54.
318 See id. at 354–55.
319 See id. at 354–56.
320 See id. at 352–54 (Gorsuch, J., dissenting). The majority and Justice Gorsuch also reached differing interpretations
regarding the extent to which nonjudicial proceedings to cancel patents were an accepted practice under English law at
the time of the framing of the Constitution. Compare id. at 340–42 (majority opinion, noting practice of vacating
patents via petitions to the Privy Council), with id. at 351–52 (Gorsuch, J., dissenting, arguing that this practice had
become a “last resort” by the time of the Constitution).
321 594 U.S. 1 (2021).
322 See id. at 24–28.
323 See Cong. Rsch. Serv., Officer and Non-Officer Appointments, CONSTITUTION ANNOTATED,
https://constitution.congress.gov/browse/essay/artII-S2-C2-3-10/ALDE_00013100/ (last visited Mar. 28, 2024).
324 U.S. CONST. art. II, § 2, cl. 2.
325 See Arthrex, 594 U.S. at 9–14.
326 Id. at 23.
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The AIA, as written, did not subject the APJs’ IPR decisions to “review by a superior executive
officer,” such as the USPTO Director.327 The Court reasoned that only principal officers
nominated by the President and confirmed by the Senate may make “final decision[s] binding the
Executive Branch” in administrative adjudications such as IPRs.328 Under the AIA, however, only
PTAB itself (not the USPTO Director) could grant rehearing of PTAB decisions, giving APJs the
final word of the executive branch on PTAB’s patentability decisions in IPRs.329 In short, the
Court held that the structure of PTAB violated the Constitution because it gave inferior officers
(APJs) “unreviewable executive power.”330
Despite this constitutional flaw, the Court did not invalidate the PTAB itself or the administrative
processes created by the AIA. Instead, it concluded that the appropriate remedy was to grant the
Director unilateral power to review PTAB decisions.331 Although the AIA specifically insulated
PTAB decisions from further review within the executive branch—providing that “[o]nly the
[PTAB] may grant rehearings”332—the Court severed (or invalidated) this statutory provision to
save the remainder of the statute.333 Arthrex thus gave the Director “discretion” to rehear PTAB
decisions.334 The Court reasoned that this remedy was sufficient since APJs are inferior officers
“[i]n every respect save the insulation of their decisions from review within the Executive
Branch.”335
Justice Gorsuch joined the majority opinion on the merits but dissented as to the appropriate
remedy.336 He argued that the Court’s “severance” doctrine—in which the Court excises part of a
statute to cure a constitutional problem—is inappropriate when there is more than “one possible
way” to cure the constitutional problem and Congress has not provided any specific direction.337
Justice Gorsuch argued the Court should instead decline to enforce the statute—in this case,
allowing challengers to vacate PTAB decisions until Congress fixed the constitutional
problem338—to avoid guessing “what a past Congress would have done.”339
Justice Thomas, joined in part by Justices Breyer, Sotomayor, and Kagan, dissented as to the
merits of the Appointments Clause question, arguing that the PTAB’s structure was consistent
with the Constitution.340 Justice Thomas argued APJs are inferior officers because they are “lower
in rank to at least two different officers”—the Director and the Secretary341—and because the
Director has a number of tools to supervise and control APJs, making them “functionally”
inferior.342 For instance, the AIA allows the Director to decide whether to institute an IPR, control

327 Id. at 14.
328 Id. at 23.
329 See id. at 23–27 (discussing 35 U.S.C. § 6(c)).
330 Id. at 18–19.
331 See id. at 23–28.
332 35 U.S.C. § 6(c).
333 Arthrex, 594 U.S. at 23–25.
334 Id. at 27–28.
335 Id. at 23–25.
336 See id. at 27–28 (Gorsuch, J., dissenting).
337 Id. at 30–32.
338 See id.
339 Id. at 34–35.
340 See id. at 43–46 (Thomas, J., dissenting).
341 Id. at 48–50.
342 Id.
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which APJs are assigned to the panel, and add additional members (including the Director) to
panels.343
Justice Breyer, joined by Justices Sotomayor and Kagan, issued a separate opinion dissenting on
the merits, arguing that the Appointments Clause grants Congress “a degree of leeway”344 and
that the Court should “take account of . . . why Congress enacted a particular statutory limitation”
and consider the “practical consequences” of that choice.345 Here, Justice Breyer argued, the
“technical nature of patents, the need for expertise, and the importance of avoiding political
interference” justified Congress’s decision to give APJs a degree of independence.346
Current Debates and Proposed Reforms
PTAB has administered AIA post-grant proceedings for more than a decade. As PTAB has gained
experience with these new types of proceedings—and developed rules, operating procedures,
guidelines, and precedential decisions for them—several issues have attracted attention and
differing views from stakeholders. Some of these issues include the proper role of the USPTO
Director and PTAB management in PTAB proceedings (especially following Arthrex); who
should be able to file petitions; the proper standards for proving invalidity and for claim
construction; and the circumstances when PTAB should deny institution of an IPR.
This section of the report explains PTAB’s current practices in these areas and selected proposed
reforms, including the Promoting and Respecting Economically Vital American Innovation
Leadership Act (PREVAIL Act), introduced in the 118th Congress as S. 2220,347 and several
proposed rulemaking notices published by USPTO.348 This section discusses how selected
provisions in the PREVAIL Act and USPTO’s proposed rules would reform certain aspects of
PTAB.349
What Roles Do the USPTO Director and PTAB Management Play
in PTAB Decisions?
Interim Director Review Process
As discussed above, the Supreme Court’s 2021 Arthrex decision gave the USPTO Director
unilateral power to review PTAB’s decisions and invalidated a provision of the AIA to the extent

343 See id. at 50–53.
344 Id. at 38 (Breyer, J., dissenting).
345 Id. at 41.
346 Id. at 41.
347 See PREVAIL Act, S. 2220, 118th Cong. (2023). An identical bill has been introduced in the U.S. House of
Representatives as H.R. 4370, 118th Cong. (2023).
348 See Patent Trial and Appeal Board Rules of Practice for Briefing Discretionary Denial Issues, and Rules for 325(d)
Considerations, Instituting Parallel and Serial Petitions, and Termination Due to Settlement Agreement, 89 Fed. Reg.
28693 (Apr. 19, 2024) [hereinafter Discretionary Denial NPRM]; Rules Governing Director Review of Patent Trial and
Appeal Board Decisions, 89 Fed. Reg. 26807 (April 16, 2024) [hereinafter Director Review NPRM]; Changes Under
Consideration to Discretionary Institution Practices, Petition Word-Count Limits, and Settlement Practices for America
Invents Act Trial Proceedings Before the Patent Trial and Appeal Board, 88 Fed. Reg. 24503 (Apr. 21, 2023)
[hereinafter ANPRM].
349 This section does not comprehensively review all of the proposed changes in the PREVAIL Act and proposed
rulemaking notices. For example, this section does not analyze PREVAIL Act’s provisions on real parties-in-interest or
USPTO fee diversion.
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that it prohibited director review.350 Days after the Court decided Arthrex, USPTO implemented
the decision by establishing an “Interim Director Review Process” that allows parties to seek
director review of PTAB decisions.351 Although the Arthrex decision concerned only IPR,352 the
Interim Director Review Process applies to PGR and derivation proceedings as well.353
As currently designed, the Interim Director Review Process allows parties to request director
review of PTAB’s (1) institution decisions, (2) final written decisions, and (3) decisions granting
requests for rehearing.354 Requests for director review are limited to decisions that present either
an abuse of discretion or “important issues of law or policy,” except that requests for review of
final written decisions may also seek review of allegedly erroneous findings of material fact or
legal conclusions.355 Requests for director review may not include new evidence or arguments not
already in the record.356 A body called the Advisory Committee, comprising at least 11 members
from various USPTO business units, reviews requests for director review and makes
recommendations on whether or not the Director should grant review.357
If the Director grants review, she generally makes a decision based on the existing record but may
order additional briefing, discovery, or oral argument.358 The Director reviews PTAB decisions de
novo (i.e., without giving any deference to PTAB), except for decisions whether to institute a trial
or grant rehearing that do not involve important issues of law and policy, which are reviewed only
for abuse of discretion.359
In addition to reviews requested by a party, the Director has authority to review PTAB decisions
sua sponte (i.e., of her own volition).360 Whereas parties may request review only of certain kinds
of decisions, the Director may review any PTAB decision sua sponte.361 The Director may seek
recommendations from the Advisory Committee whether or not to review a decision sua
sponte.362 The Director may—but is not required to—give the parties an opportunity to submit
briefing on sua sponte reviews.363

350 Arthrex, 594 U.S. at 25 (“We conclude that a tailored approach is the appropriate one: Section 6(c) cannot
constitutionally be enforced to the extent that its requirements prevent the Director from reviewing final decisions
rendered by APJs.”).
351 See USPTO, Revised Interim Director Review Process, https://www.uspto.gov/patents/ptab/decisions/revised-
interim-director-review-process (last visited Mar. 28, 2024) [hereinafter Interim Director Review Process]; Request for
Comments on Director Review, Precedential Opinion Panel Review, and Internal Circulation and Review of Patent
Trial and Appeal Board Decisions, 87 Fed. Reg. 43249 (July 20, 2022) [hereinafter Request for Comments on Director
Review] (“On June 29, 2021, the USPTO implemented an interim process for Director review.”).
352 Arthrex, 594 U.S. at 26 (“[T]his suit concerns only the Director's ability to supervise APJs in adjudicating petitions
for inter partes review. We do not address the Director’s supervision over other types of adjudications conducted by the
PTAB.”).
353 See Interim Director Review Process, supra note 351, Section 1.
354 See id., Section 2.A.
355 See id., Section 2.B.
356 See id., Section 3.E.
357 See id., Section 4.A.
358 See id., Section 4.A.ii.
359 See id., Section 5.C.
360 See id., Section 4.C.
361 See id., Section 2.A.
362 See id., Section 4.A.
363 See id., Section 4.C.
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If the Director decides to review a PTAB decision, either upon request of a party or sua sponte,
she may choose to delegate the review to a Delegated Rehearing Panel (DRP).364 A DRP is
composed of APJs who did not serve on the initial panel.365 Whether or not the Director delegates
review to a DRP, the process concludes with a decision that affirms, reverses, modifies, or vacates
the PTAB’s decision; remands the decision for further PTAB proceedings; or some combination
of the above. Review decisions constitute final written decisions that may be appealed to the
Federal Circuit,366 and a party may also request rehearing of a review decision.367
In April 2024, USPTO published a notice of proposed rulemaking (NPRM) that proposes to
codify in USPTO regulations a director review process that generally “is consistent with the
current interim process.”368 The proposed rule deviates from the current Interim Director Review
Process in some respects, however. As commentators have noted,369 the proposed rule would not
expressly limit the grounds to request director review, as the Interim Director Review Process
does (i.e., limiting director review to decisions presenting an abuse of discretion, important issues
of law or policy, and—for final written decisions only—erroneous findings of material fact or
erroneous legal conclusions).370 The proposed rule would also require that, if the Director grants
review and does not withdraw the grant, the review must conclude with “a decision or order that
provides the reasons for the Director’s disposition of the case.”371 In addition, the proposed rule
would prohibit communications from third parties from being considered in the review process,
except for “authorized amicus briefing.”372
Concerns Regarding Transparency and APJ Independence
While the Interim Director Review Process governs director review of already-issued decisions,
PTAB’s management has utilized various other practices for oversight and peer review of draft
decisions before they are issued.373 Some stakeholders have raised concerns about the
transparency of these practices and their potential effects on the independence of APJs.374
In December 2022, the U.S. Government Accountability Office (GAO) issued a report making
recommendations that included “specifying in finalized policies PTAB management and USPTO
Director roles in internal oversight processes and circumstances in which judges are required to
incorporate management comments” in their decisions.375 GAO noted that some stakeholders and
APJs were uncertain about the role of the Director and PTAB management in overseeing panel

364 See id., Section 5.A.iii
365 See Delegated Rehearing Panel, Section 2.A (“The DRP shall be selected from the Chief Judge, Deputy Chief
Judge, Vice Chief Judges, and Senior Lead Judges, excluding judges who served on the original Board panel for the
case under review or otherwise have a conflict with the case.”).
366 See Interim Director Review Process, supra note 351, Section 5.C.i.
367 See id., Section 5.C.ii.
368 Director Review NPRM, supra note 348, at 26810.
369 See Kassandra M. Officer et al., USPTO Publishes Notice of Proposed Rulemaking for Director Review, FINNEGAN
(April 2024), https://www.finnegan.com/en/insights/blogs/at-the-ptab-blog/uspto-publishes-notice-of-proposed-
rulemaking-for-director-review.html.
370 Compare Director Review NPRM, supra note 348, at 26813 with Interim Director Review Process, supra note 351,
Section 2.B.
371 Director Review NPRM, supra note 348, at 26813.
372 Id.
373 See generally GAO PTAB REPORT, supra note 102, at 14 (providing timeline of PTAB oversight mechanisms).
374 See id. at 41–42 (making recommendations to USPTO Director).
375 Id. at “Highlights” page.
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decisions.376 One area of uncertainty concerned whether panels were required to incorporate
comments management provided on draft decisions.377
The GAO report also explored to what extent, if at all, PTAB management might change or
expand the composition of PTAB panels to influence case outcomes.378 Eighty percent of APJs
surveyed by GAO reported experiencing panel changes, 20% of whom felt that such changes
were made “to alter or influence” panel decisions.379 PTAB management reported that it was
“exceptionally rare to use paneling as a vehicle for oversight.”380 Overall, 75% of judges
responded that oversight practices “had an effect on their independence.”381
In October 2023, PTAB issued a standard operating procedure (SOP 4)382 to address some of the
issues discussed in the GAO report.383 SOP 4 allows panel members to request nonbinding input
on draft decisions from a pool of “non-management peer judges”384 and/or from a review team
designated by PTAB Executive Management, which consists of the Chief Judge, Deputy Chief
Judge, Vice Chief Judges, and Senior Lead Judges.385 SOP 4 gives PTAB panel members
discretion whether or not to solicit input from these bodies and gives PTAB panels “final
authority and responsibility for the content of a decision,” including “in what manner, if at all, to
incorporate any feedback.”386 SOP 4 gives a third body responsibility for reviewing issued
decisions to determine whether they require further attention, such as sua sponte Director
review.387
SOP 4 states that the Director will not be involved in directing or influencing panel decisions
before they issue (unless the Director is a member of the panel).388 SOP 4 also states that the
Director will not influence paneling decisions prior to issuance of a decision, but she may direct
repaneling when reviewing or rehearing an issued decision.389
The PREVAIL Act contains provisions that its sponsors contend would increase transparency of
PTAB proceedings.390 It would require the Director to issue a separate written opinion in the
public record that sets forth the reasons for any reconsideration, rehearing, or review of an IPR or

376 Id. at 33.
377 Id. at 29–31.
378 Id. at 36.
379 Id. at 36.
380 Id. at 36 n. 78.
381 Id. at 23.
382 PTAB, STANDARD OPERATING PROCEDURE 4: PROCEDURE FOR PRE-ISSUANCE OPTIONAL DECISION REVIEW AND POST-
ISSUANCE DECISION REVIEW (Oct. 2023), https://www.uspto.gov/sites/default/files/documents/ptab_sop_4-2023-oct.pdf
[hereinafter SOP 4].
383 In its report, GAO noted that some of these changes had previously been incorporated into the Interim Director
Review Process as of May 2022. See GAO PTAB REPORT, supra note 102, at “Highlights” page. GAO stated that such
changes could improve transparency about oversight practices “if finalized and . . . made publicly available.” Id.
384 SOP 4, supra note 382, at 1–2 (a Circulation Judge Pool or CPJ).
385 Id. at 3–4 (PTAB Management Pre-Issuance Optional Review team).
386 Id. at 1.
387 Id. at 5 (PTAB Post-Issuance Review team).
388 Id. at 4–5.
389 Id. at 5.
390 THE PREVAIL ACT WILL HELP ENSURE U.S. GLOBAL TECHNOLOGY LEADERSHIP AND PROTECT ECONOMIC AND
NATIONAL SECURITY 2, https://www.coons.senate.gov/imo/media/doc/prevail_act_fact_sheet.pdf (last visited Mar. 28,
2024) [hereinafter PREVAIL ACT FACT SHEET].
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PGR decision.391 The bill’s sponsors state that this requirement would “increase transparency and
reduce concerns that the Director unfairly influences PTAB decisions.”392 The bill would also
require that any changes to the membership of a panel be noted in the public record.393
The PREVAIL Act would also require the Director—and any other officers with disciplinary or
supervisory authority over APJs—to “refrain from communications with [a PTAB panel] that
direct or otherwise influence any merits decision.”394 Some commentators would like to see this
provision go further by extending this prohibition on so-called “ex parte contacts” to institution
and procedural decisions.395 Some have also called on Congress to restore APJs’ pre-Arthrex
independence by requiring that they be appointed by the President and confirmed by the Senate,
thus making them superior officers who may constitutionally be insulated from Director
supervision.396
Who Has Standing to Petition PTAB and Appeal Its Decisions?
Although many IPRs are brought by persons sued for patent infringement in court, being sued or
threatened with suit is not a requirement to bring an IPR or PGR petition. Under the AIA, any
person other than the patent holder may file an IPR or PGR petition.397 By contrast, parties may
challenge patents in federal court only if there is “a substantial controversy, between the parties
having adverse legal interests, of sufficient immediacy and reality.”398
The lack of a standing requirement means that a broader set of people and groups may use IPR
and PGR, even if they do not make products that could infringe the challenged patents. For
example, public interest and nonprofit groups, such as the Electronic Frontier Foundation399 and
Consumer Watchdog,400 have used IPRs to challenge patents. In addition, some IPRs are brought
by petitioning organizations that receive funding from companies that may be sued for patent
infringement. For example, Unified Patents—an organization whose members include many large
technology companies401—is among the most frequent users of IPR.402

391 PREVAIL Act, S. 2220, 118th Cong. § 4(f), 5(f) (2023).
392 PREVAIL ACT FACT SHEET, supra note 390, at 2.
393 S. 2220 § 3.
394 S. 2220 § 3.
395 See Written Statement of Joseph Matal, Reforming the Patent Trial and Appeal Board—The PREVAIL Act and
Proposals to Promote U.S. Innovation Leadership: Hearing Before the Senate Comm. on the Judiciary, Subcomm. on
Intellectual Property, 118th Cong. (Nov. 8, 2023), https://www.judiciary.senate.gov/download/2023-11-08-testimony-
matal, at 17 [hereinafter Matal Statement].
396 See id. at 18.
397 35 U.S.C. §§ 311(a), 321(a).
398 Prasco LLC v. Medicis Pharm. Corp., 537 F.3d 1329, 1334 (Fed. Cir. 2008) (quoting MedImmune, Inc. v.
Genentech, Inc., 549 U.S. 118, 127 (2007)).
399 See Pers. Audio, LLC v. Elec. Frontier Found., 867 F.3d 1246 (Fed. Cir. 2017) (appeal from IPR brought by the
Electronic Frontier Foundation).
400 See Consumer Watchdog v. Wis. Alumni Rsch. Found., 753 F.3d 1258 (Fed. Cir. 2014) (appeal from IPR brought
by Consumer Watchdog).
401 See UNIFIED PATENTS, Members, https://www.unifiedpatents.com/members (last visited Mar. 28, 2024).
402 See UNIFIED PATENTS, 2022 Annual PTAB Report, https://portal.unifiedpatents.com/ptab/annual-report (last visited
Mar. 28, 2024) (listing Unified Patents as the sixth most active PTAB petitioner in 2022, behind Apple, Inc., Samsung
Electronics Co., Google LLC, Samsung Electronics America, and Amazon.com).
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The PREVAIL Act would restrict who may file petitions for IPR (but not for PGR).403 The bill’s
language would allow a person to file an IPR petition only if they have been sued for infringing
the patent or “charged with infringement” of the patent.404 The latter term is defined to mean a
“real and substantial controversy” of the sort required for standing in federal court.405
Supporters of this standing requirement contend it would encourage independent and small
business inventors to develop and seek patent protection for new inventions by giving them
assurance that the patents would not be challenged unless they assert them against alleged
infringers.406 Opponents argue that restricting standing in this manner would stop petitioning
organizations and others from filing petitions against low-quality patents used by “nuisance-
settlement plaintiffs” that file abusive patent infringement lawsuits against parties who cannot,
individually, afford to litigate such lawsuits.407 Opponents also argue that restrictions on standing
could reduce consumer choices and raise prices by preventing businesses from filing “clearance
petitions” to gain assurance that they can commercialize products without risking patent
infringement.408
What Should Be PTAB’s Standards for Invalidation and Claim
Construction?
Invalidity: Preponderance of Evidence or Clear and Convincing Evidence?
One difference between district court litigation and IPRs and PGRs is the standard of proof
needed to invalidate a patent. The Patent Act provides that patents are presumed to be valid.409
Based on that presumption, the Supreme Court and the Federal Circuit have held that district
courts may invalidate a patent only if there is “clear and convincing evidence” of invalidity.410
The AIA, on the other hand, allows IPR and PGR petitioners to show that a patent is invalid by a
lower standard: the “preponderance of the evidence.”411
The sponsors of the PREVAIL Act propose to “harmonize” these standards by holding PTAB
challengers to the higher, “clear and convincing evidence” standard used in district court.412 Thus,
the PREVAIL Act would place the burden on the petitioner in an IPR or PGR to prove the
unpatentability of a previously issued claim of a patent by clear and convincing evidence.413

403 S. 2220, 118th Cong. § 4(a).
404 Id.
405 Id.; see generally MedImmune, 549 U.S. at 126–36.
406 See Written Statement of Michelle E. Armond, Reforming the Patent Trial and Appeal Board—The PREVAIL Act
and Proposals to Promote U.S. Innovation Leadership: Hearing Before the Senate Comm. on the Judiciary, Subcomm.
on Intellectual Property, 118th Cong. (Nov. 8, 2023), https://www.judiciary.senate.gov/download/2023-11-08-
testimony-armond, at 12 [hereinafter Armond Statement].
407 See Matal Statement, supra note 395, at 12–14.
408 See id. at 11–12 (arguing many clearance petitions are directed against patents owned by NPEs).
409 35 U.S.C. § 282 (“A patent shall be presumed valid.”).
410 Microsoft Corp. v. i4iLP, 564 U.S. 91, 95 (2011). The Supreme Court noted in its opinion that the Federal Circuit—
the appellate court with jurisdiction over patent litigation—had required the same “clear and convincing evidence”
standard since 1984. See id. at 97 (“In the nearly 30 years since American Hoist, the Federal Circuit has never wavered
in this interpretation of § 282.” (citing Am. Hoist & Derrick Co. v. Sowa & Sons, Inc., 725 F.2d 1350 (Fed. Cir.
1984))).
411 35 U.S.C. § 316(e).
412 PREVAIL ACT FACT SHEET, supra note 390, at 2.
413 S. 2220, 118th Cong. §§ 4(d)(2), 5(d)(2).
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(With respect to substitute claims proposed by the patentee during an IPR or PGR, however, the
petitioner would have only “the burden of persuasion, by a preponderance of the evidence,” to
show unpatentability.414)
Proponents of this change contend that it would “promote consistency by harmonizing standards
between the PTAB and district court.”415 Opponents argue that, while it is appropriate for district
courts to give “deference to the expert agency [USPTO] that issued the patent” by using the clear-
and-convincing-evidence standard to invalidate a patent, USPTO should not be required to defer
to its own earlier decision to grant a patent, and therefore PTAB should continue to use the lower
preponderance-of-evidence standard in AIA proceedings.416
Claim Construction: Should USPTO or Congress Decide the Right Standard?
PTAB previously used a different standard than district courts for the construction (i.e.,
interpretation) of patent claims. Before 2018, PTAB gave claims their “broadest reasonable
construction” (BRC),417 the standard used by USPTO during patent prosecution.418
District courts and the ITC, by contrast, construe claims according to a standard articulated by the
Federal Circuit in its 2005 opinion in Phillips v. AWH Corp.419 The Phillips standard requires the
adjudicator to construe claim terms according to their “ordinary and customary meaning . . . to a
person of ordinary skill in the art in question at the time of the invention.”420 To discern this
meaning, courts must look to the claim themselves, the patent specification, documents from the
prosecution of the patent (prosecution history), and, to a lesser degree, “extrinsic evidence” such
as expert testimony, dictionaries, and treatises.421 Construing claims under the Phillips standard
tends to result in a narrower scope of patent claims than the BRC standard, potentially making it
harder for patentees to prove patent infringement (since fewer accused articles may fall within the
claims) but easier to defend patent validity (since less prior art may anticipate the claims or render
them obvious).
In 2018, USPTO issued a final rule requiring PTAB to use the Phillips standard instead of the
BRC standard to construe patent claims in AIA proceedings.422 Thus, PTAB now applies the same
claim construction standard used in district courts and the ITC. USPTO noted that the majority of
comments it received supported this change.423 USPTO cited the benefits of “greater uniformity
and predictability” and “judicial efficiency” as reasons for PTAB to use the same claim
construction standard as districts courts and the ITC, especially since many patents subject to AIA
proceedings are also involved in litigation in those forums.424 USPTO also noted that the rule

414 S. 2220, 118th Cong. §§ 4(d)(2), 5(d)(2).
415 Armond Statement, supra note 406, at 11.
416 Matal Statement, supra note 395, at 9.
417 Cuozzo Speed Techs., LLC v. Lee, 579 U.S. 261, 270 (2016) (citing 37 C.F.R. § 42.100(b)).
418 Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc) (“The Patent and Trademark Office . . .
determines the scope of claims in patent applications not solely on the basis of the claim language, but upon giving
claims their broadest reasonable construction ‘in light of the specification as it would be interpreted by one of ordinary
skill in the art.’” (quoting In re Am. Acad. of Sci. Tech. Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004))).
419 See id.
420 Id. at 1313.
421 See id. at 1313–19.
422 See Changes to the Claim Construction Standard for Interpreting Claims in Trial Proceedings Before the Patent Trial
and Appeal Board, 83 Fed. Reg. 51340 (Oct. 11, 2018) (codified at 37 C.F.R. § 42.100(b)).
423 See id. at 51345.
424 Id. at 51342.
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addresses “potential unfairness” that some patent owners believed could result from PTAB
construing claim terms more broadly than other forums.425 PTAB’s use of the Phillips standard
does not necessarily mean PTAB, district courts, and the ITC reach identical constructions of
specific claims or claim terms, although the 2018 rule requires PTAB to “consider” prior district
court or ITC constructions that are “timely made of record” in AIA proceedings.426
The PREVAIL Act essentially seeks to codify the 2018 rule change so that PTAB would be
statutorily required to continue using the Phillips standard.427 Currently, as the Supreme Court
held in Cuozzo, the AIA “leaves open the question of which claim construction standard is
proper” and gives USPTO authority to select the proper standard through rulemaking.428 USPTO
exercised this authority when it initially adopted the BRC standard and, later, when it switched to
the Phillips standard. The PREVAIL Act would remove this authority from USPTO and prevent it
from reverting to the BRC standard or adopting any other alternative claim construction standard
for PTAB.
When Should PTAB Deny Institution of an IPR?
As noted above, the AIA gives PTAB discretion to deny institution of an IPR. Questions about
when and how PTAB should exercise this discretion often arise in situations where a single patent
is challenged multiple times or in multiple forums, including the following:
• Previously Addressed Prior Art and Arguments. An IPR raises the same prior
art or arguments already considered by PTAB in an earlier petition or during
initial examination.
• Parallel Petitions. A party files multiple IPRs against the same patent at or about
the same time (e.g., based on different legal arguments or prior art).
• Serial Petitions. A party files subsequent IPRs against the same patent claims
following an initial petition by the same party challenging those claims.
• Parallel District Court Litigation. A party files an IPR against patent claims
that are the subject of ongoing district court litigation.
• Patents Already Adjudicated in Court. A party files an IPR challenging the
validity of a patent that has already been litigated and upheld as valid in court.
This section discusses how PTAB currently approaches each of these scenarios and how some
Members of Congress and USPTO have proposed to reform PTAB’s practice in this area. As
explained below, the PREVAIL Act would change PTAB’s practices in the above-listed scenarios
in various ways. In addition, in April 2024, USPTO published a Notice of Proposed Rulemaking
(NPRM) that would affect PTAB’s discretionary denial practice in three of these scenarios—
previously addressed prior art and arguments, parallel petitions, and serial petitions—as detailed
below.429 In 2023, USPTO had published an Advance Notice of Proposed Rulemaking (ANPRM)

425 See id. (“Because the [BRC] standard potentially reads on a broader universe of prior art than does the Phillips
standard, a patent claim could potentially be found unpatentable in an AIA proceeding on account of [a broader] claim
scope that the patent owner would not be able to assert in an infringement proceeding.”).
426 Id. at 51358–59 (codified at 37 C.F.R. §§ 42.100(b), .200(b)).
427 See S. 2220, 118th Cong. § 4(d)(3), 5(d)(3).
428 Cuozzo, 579 U.S. at 279–80.
429 See Discretionary Denial NPRM, supra note 348, at 28704–05. In addition, this NPRM would allow parties to file
separate briefing on discretionary denial issues. See id. at 28704 (allowing petitioner and patent owner to file papers
regarding whether there is good cause to institute parallel petitions), 28703–04 (allowing patent owner to file request
(continued...)
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that would also have changed PTAB’s practices regarding parallel district court litigation and
patents already adjudicated in district court.430 The April 2024 NPRM on discretionary denial
issues did not include proposed rules on those two scenarios but noted that USPTO “continues to
consider issuing proposed rules” on issues raised in the ANPRM.431
Petitions Raising Previously Presented Prior Art and Arguments
As noted above, when PTAB decides whether or not to institute an IPR, 35 U.S.C. § 325(d)
authorizes USPTO to consider whether “substantially the same prior art or arguments” were
“previously presented” to USPTO.432 This may occur when an IPR petition raises prior art or
arguments that USPTO considered during its initial examination (i.e., prosecution) of the patent,
earlier AIA proceedings (i.e., earlier IPRs or PGRs), or other USPTO proceedings.433
PTAB currently applies a two-part test to decide whether to deny institution under
Section 325(d).434 PTAB considers first whether “the same or substantially the same” prior art or
arguments were previously presented to USPTO.435 If so, PTAB then considers “whether the
petitioner has demonstrated that the Office erred in a manner material to the patentability of
challenged claims.”436
In applying the first part of the test, PTAB may consider “similarities and material differences
between the asserted art and the prior art involved during examination,” “the cumulative nature of
the asserted art and the prior art evaluated during examination,” and “the extent of the overlap
between the arguments made during examination and the manner in which the petitioner relies on
the prior art or the patent owner distinguishes the prior art.”437 For the second part of the test,
PTAB may consider “the extent to which the asserted art was evaluated during examination,
including whether the prior art was the basis for rejection,” “whether the petitioner has pointed
out sufficiently how the examiner erred in its evaluation of the asserted prior art,” and “the extent
to which additional evidence and facts presented in the petition warrant reconsideration of the
prior art or arguments.”438
In its NPRM on discretionary denial issues, USPTO has proposed a rule that would limit
Section 325(d) denials based on previously presented prior art to circumstances in which “the
same or substantially the same prior art was previously meaningfully addressed” by USPTO with
regard to the same or a related patent.439 The proposed rule provides that prior art is considered
“substantially the same” only if “the disclosure in the prior art previously addressed contains the

for discretionary denial on grounds other than parallel petitions, with an opportunity for petitioner and patent owner to
file opposition to and reply in support of the request, respectively).
430 See ANPRM, supra note 348, at 24510 (prior adjudications upholding validity), 24513–17 (parallel litigation).
431 Discretionary Denial NPRM, supra note 348, at 28695.
432 35 U.S.C. § 325(d).
433 See ANPRM, supra note 348, at 24512 (noting such other proceedings including reissue, ex parte reexamination,
and inter partes reexamination).
434 See Advanced Bionics, LLC v. Med-El Elektromedizinische Geräte GmbH, IPR2019–01469, Paper 6 at 8 (P.T.A.B.
Feb. 13, 2020) (precedential); ANPRM, supra note 348, at 24511.
435 See ANPRM, supra note 348, at 24511.
436 Id. at 24511 (citing Advanced Bionics).
437 Id. at 24511 (citing Becton, Dickinson & Co. v. B. Braun Melsungen AG, IPR2017–01586, Paper 8, at 17–18
(P.T.A.B. Dec. 15, 2017) (precedential as to Section III.C.5, first paragraph)).
438 Id.
439 Discretionary Denial NPRM, supra note 348, at 28705.
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same teaching relied upon in the [PTAB] petition.”440 It also provides that prior art is
“meaningfully addressed” only “when [USPTO] has evaluated the art or arguments and
articulated its consideration of the art or arguments in the record.”441
The proposed rule provides that, even if USPTO meaningfully addressed prior art at an earlier
time, an IPR may be instituted if the petitioner establishes material error by USPTO.442 USPTO
explains that material error could include errors of law—such as incorrect claim term
constructions—and overlooking teachings of the relevant prior art.443
The PREVAIL Act would impose a bright-line rule that PTAB must reject an IPR or PGR petition
“that presents prior art or an argument that is the same or substantially the same as prior art or an
argument that previously was presented to the [USPTO].”444 The sponsors contend that this
requirement would prevent “costly and inefficient” proceedings involving the same prior art
already considered by USPTO.445 Critics argue that this bill would require PTAB to deny
institution of IPRs involving any prior art that was previously “presented” to USPTO, whether or
not USPTO had actually considered that prior art—potentially incentivizing patent applicants to
“immunize” their patents against future challenges by disclosing more prior art references than
the examiner can “meaningfully consider.”446
Serial Petitions
Serial PTAB petitions refer to when a petitioner files a second IPR or PGR attacking the same
patent claims it challenged in an earlier petition, after the preliminary response to the first
petition.447
Based on the “potential for abuse” through “repeated attacks on patents,” PTAB precedent sets
out several nonexclusive factors (sometimes called the General Plastic factors) that it considers
in deciding whether to exercise its discretion to decline to institute a serial IPR.448 Those factors
are
1. whether the same petitioner previously filed a petition directed to the same claims of the
same patent;
2. whether at the time of filing of the first petition the petitioner knew of the prior art
asserted in the second petition or should have known of it;
3. whether at the time of filing of the second petition the petitioner already received the
patent owner’s preliminary response to the first petition or received [PTAB’s] decision
on whether to institute review in the first petition;
4. the length of time that elapsed between the time the petitioner learned of the prior art
asserted in the second petition and the filing of the second petition;

440 Id. at 28705.
441 Id.
442 See id. at 28705.
443 See id. at 28700–01.
444 S. 2220, 118th Cong. §§ 4(c)(1)(E), 5(c)(3).
445 PREVAIL ACT FACT SHEET, supra note 390, at 3.
446 Matal Statement, supra note 395, at 10–11.
447 See ANPRM, supra note 348, at 24510.
448 Gen. Plastic Indus. Co. v. Canon Kabushiki Kaisha, IPR2016-01357, at 16–17 (P.T.A.B. Sept. 16, 2017)
(precedential).
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5. whether the petitioner provides adequate explanation for the time elapsed between the
filings of multiple petitions directed to the same claims of the same patent;
6. the finite resources of [PTAB]; and
7. the requirement under 35 U.S.C. § 316(a)(11) to issue a final determination not later than
1 year after the date on which the Director notices institution of review.449
The first factor essentially considers whether a subsequent petition should be considered a “serial
petition” at all. In applying this factor, PTAB considers not only whether the named petitioner has
previously petitioned to invalidate the claims at issue but also whether parties in “privity” with
the petitioner have done so.450 PTAB has, for instance, exercised its discretion to deny a petition
where one of the petitioner’s licensees—who was also the petitioner’s codefendant in a parallel
district court suit—had previously petitioned to cancel the same claims.451 The first factor
likewise weighs against institution where the petitioner previously joined an already-instituted
IPR on the same patent claims.452
USPTO’s NPRM on discretionary denial issues defines a serial petition as one that challenges the
“same or overlapping claims of the same patent that have already been challenged by the
petitioner, the petitioner’s real party in interest, or a privy of the petitioner” and is filed after the
time the patent owner files their preliminary response or, if no preliminary response is filed, the
deadline for such response.453 The NPRM proposes a rule to codify “substantially the same
factors” to evaluate serial petitions as General Plastics, with the goal of balancing the interests of
“preventing undue harassment by patent owners” and “allowing petitioners reasonable
opportunities to seek review.”454 The factors set forth in USPTO’s proposed rule, corresponding to
the second through fifth General Plastics factors, are:
(1) Whether, at the time of filing of the first petition, the petitioner knew of the prior art
asserted in the second petition or should have known of it;
(2) Whether, at the time of filing of the second petition, the petitioner had already received
the patent owner preliminary response to the first petition or had received [PTAB’s]
decision on whether to institute review in the first petition;
(3) The length of time that elapsed between the time the petitioner learned of the prior art
asserted in the second petition and the filing of the second petition; and
(4) Whether the petitioner provided an adequate explanation for the time elapsed between
the filings of multiple petitions directed to the same claims of the same patent.455
The PREVAIL Act contains an estoppel provision that would generally prohibit serial petitions.
The estoppel provision would generally prohibit a petitioner who has “previously requested” an
IPR on any claim in a given patent, a real party in interest, or a privy of the petitioner to request
or maintain another “proceeding” before USPTO on a ground that the petitioner “raised or
reasonably could have raised” in the previous IPR petition.456 The sole exception to this rule

449 Id. at 16.
450 ANPRM, supra note 348, at 24507.
451 Valve Corp. v. Elec. Scripting Prods., Inc., IPR2019-00062, -00063, -00084, 2019 WL 1490575 (P.T.A.B. Apr. 2,
2019) (precedential) (Valve I).
452 See ANPRM, supra note 348, at 24507; Valve Corp. v. Elec. Scripting Prods., Inc., IPR2019-00064, -00065, -
00085, 2019 WL 1965688 (P.T.A.B. May 1, 2019) (Valve II).
453 Discretionary Denial NPRM, supra note 348, at 28703.
454 Id. at 28699.
455 Id. at 28706.
456 S. 2220, 118th Cong. § 4(c)(1)(F).
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applies where, after filing the initial IPR petition, the petitioner, party in interest, or privy is
“charged with infringement of additional claims of the patent” and requests a subsequent IPR
solely on such additional claims.457
Parallel Petitions
A distinct but similar practice to serial petitions, “parallel” PTAB petitions, refers to a petitioner
filing multiple IPRs and PGRs attacking the same patent on different grounds at or about the
same time.458 One reason that petitioners sometimes file parallel petitions attacking the same
patent is that PTAB rules impose limits on the length of each petition and subsequent briefing.459
Thus, parallel petitions allow the petitioner more space to explicate arguments for each ground
for invalidation. At the same time, USPTO notes that parallel petitions “may place a substantial
and unnecessary burden on the patent owner and could raise fairness, timing, and efficiency
concerns.”460 PTAB may deny institution of parallel petitions.461
USPTO’s NPRM on discretionary denial issues defines parallel petitions as two or more petitions
challenging the same patent that are filed on or before the time the patent owner files their
preliminary response or, if no preliminary response is filed, the deadline for such response.462 The
NPRM proposes a rule under which PTAB would not institute parallel petitions unless the
petitioner shows “good cause as to why more than one petition is necessary.”463 The proposed rule
provides that information relevant to a showing of good cause might include:
(1) A petitioner’s ranking of their petitions in the order in which petitioner desires [PTAB]
to consider the merits of their petitions relative to their other parallel petitions;
(2) An explanation of the differences between the petitions and why the issues addressed
by the differences are material;
(3) The number of patent claims of the challenged patent that have been asserted by the
patent owner in district court litigation;
(4) The number of claims the petitioner is challenging;
(5) Whether there is a dispute about the priority date of the challenged patent;
(6) Whether there are alternative claim constructions that require different prior art
references on mutually exclusive grounds;
(7) Whether the petitioner lacked information, such as the identity of asserted claims, at
the time they filed the petitions;
(8) The complexity of the technology in the case; and

457 Id. § 4(c)(1)(F).
458 ANPRM, supra note 348, at 24512.
459 See 37 C.F.R. § 42.24(A)(1)(i) (14,000 word limit for IPR petition), (ii) (18,700 word limit for PGR).
460 ANPRM, supra note 348, at 24512.
461 See CONSOLIDATED PTAB PRACTICE GUIDE, supra note 136, at 59–61 (“Based on [PTAB’s] experience, one
petition should be sufficient to challenge the claims of a patent in most situations. . . . Nonetheless, [PTAB] recognizes
that there may be circumstances in which more than one petition may be necessary, including, for example, when the
patent owner has asserted a large number of claims in litigation or when there is a dispute about priority date requiring
arguments under multiple prior art references. In such cases two petitions by a petitioner may be needed, although this
should be rare.”).
462 Discretionary Denial NPRM, supra note 348, at 28703.
463 Id. at 28706.
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(9) Any other information believed to be pertinent to the good cause determination.464
The same PREVAIL Act estoppel provision that would generally prohibit serial petitions would
equally apply to prohibit parallel petitions.465 Likewise, the sole exception to that estoppel
provision—for petitions attacking additional claims of the patent that were asserted against the
petitioner, parties-in-interest, and privies after the initial petition—would apply to both serial and
parallel petitions.466 The sponsors of the PREVAIL Act argue this estoppel provision would
reduce litigation costs and give patent owners “quiet title” to their IP.467 Some opponents argue
that this “single petition” requirement would make it “impossible to effectively challenge patents”
with a large number of claims or disputed priority dates, due to the applicable word-count limits
on each petition.468
Parallel District Court Litigation
In addition to serial and parallel petitions, PTAB must often determine whether to deny institution
of an IPR on patent claims that are subject to ongoing (“parallel”) district court litigation. In a
2020 precedential decision, PTAB developed a multifactor test to determine whether to exercise
its discretion to deny an IPR in such cases.469 PTAB intended for these factors to help it determine
“whether efficiency, fairness, and the merits support the exercise of authority to deny institution
in view of an earlier trial date in the parallel [court] proceeding.”470
The six factors that PTAB is to take into account—known as the Fintiv factors—are
1. whether the court granted a stay or evidence exists that one may be granted if a
proceeding is instituted;
2. proximity of the court’s trial date to [PTAB’s] projected statutory deadline for a final
written decision;
3. investment in the parallel proceeding by the court and the parties;
4. overlap between issues raised in the petition and in the parallel proceeding;
5. whether the petitioner and the defendant in the parallel proceeding are the same party;
and
6. other circumstances that impact the [PTAB’s] exercise of discretion, including the
merits.471
In June 2022, USPTO released statistics showing that the number and percentage of Fintiv
denials peaked in the first half of FY2021 (with over 10% of all petitions being denied under the
Fintiv factors) before declining sharply afterward.472 Contemporaneous with the study, USPTO

464 Id.
465 See S. 2220, 118th Cong. § 4(c)(1)(F); see also PREVAIL ACT FACT SHEET, supra note 390, at 2 (noting that this
provision “appl[ies] estoppel at the time the [first] challenge is filed”).
466 See S. 2220, 118th Cong. § 4(c)(1)(F).
467 PREVAIL ACT FACT SHEET, supra note 390, at 2.
468 Matal Statement, supra note 395, at 8.
469 See Apple v. Fintiv, IPR2020-00019, at 5 (P.T.A.B. Mar. 20, 2020) (designated precedential May 5, 2020).
470 Fintiv, IPR2020-00019, at 6.
471 Id.
472 See USPTO, PATENT TRIAL AND APPEAL BOARD PARALLEL LITIGATION STUDY (June 2022),
https://www.uspto.gov/sites/default/files/documents/ptab_parallel_litigation_study_20220621_.pdf?utm_campaign=su
bscriptioncenter&utm_content=&utm_medium=email&utm_name=&utm_source=govdelivery&utm_term=.
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Director Vidal issued a binding guidance memorandum (the Guidance Memo) making four main
clarifications to how PTAB should apply the Fintiv factors.473
The Guidance Memo narrows or eliminates circumstances in which PTAB might otherwise deny
institution based on Fintiv. First, as a gloss on factor six, the Guidance Memo states that PTAB
should not deny institution under Fintiv if the petition “presents compelling evidence of
unpatentability,”474 meaning evidence that, “if unrebutted in trial, would plainly lead to a
conclusion that one or more claims are unpatentable by a preponderance of the evidence.”475
Second, the Guidance Memo clarified that, contrary to some past practice by PTAB, Fintiv
applies only to parallel district court litigation and should not be applied to deny institution due to
parallel proceedings in the ITC.476 Third, the Guidance Memo clarified that, under factor four,
PTAB will not deny institution based on parallel district court litigation if the petitioner stipulates
that they will not assert the same invalidity grounds in the district court case.477 Fourth, the
Guidance Memo clarified that factor two does not always weigh in favor of denial where the
district court’s scheduled trial date is prior to PTAB’s projected deadline for a final written
decision, given that scheduled trial dates may be “unreliable and subject to change.”478 Some
observers note that the number of Fintiv denials declined following the Guidance Memo.479
In its April 2023 ANPRM, USPTO proposed replacing the Fintiv factors with a “clear, predictable
rule” to streamline its decisions whether to institute an IPR on a patent involved in parallel district
court litigation.480 Under this approach, PTAB would have denied institution of any IPR if there
were parallel district court litigation involving at least one of the challenged claims if PTAB
determined the district court trial was “likely to occur” before the statutory deadline for the final
written decision in the IPR.481 In addition, the ANPRM proposed adopting a “streamlined
version” of some of the Fintiv factors in order to avoid “an unduly harsh outcome” in certain
cases.482 Finally, the ANPRM proposed “safe harbors” that would have precluded discretionary
denial where the petitioner filed a stipulation “agreeing not to pursue potentially overlapping
grounds in district court” or where the parallel district court proceeding had been stayed (i.e.,
paused by the court).483

473 USPTO, Memorandum to Members of PTAB Regarding Interim Procedure for Discretionary Denials in AIA Post-
Grant Proceedings With Parallel District Court Litigation 2 (June 2022),
https://www.uspto.gov/sites/default/files/documents/interim_proc_discretionary_denials_aia_parallel_district_court_liti
gation_memo_20220621_.pdf?utm_campaign=subscriptioncenter&utm_content=&utm_medium=email&utm_name=&
utm_source=govdelivery&utm_term=.
474 Id. at 5.
475 Id. at 4.
476 See id. at 6 (noting that, “[u]nlike district courts, the ITC lacks authority to invalidate a patent and its invalidity
rulings are not binding on either the [USPTO] or a district court).
477 See id. at 7 (citing Sotera Wireless, Inc. v. Masimo Corporation (§ II.A), IPR2020-01019, Paper 12 (Dec. 1, 2020)
(designated precedential Dec. 17, 2020)).
478 Id. at 8.
479 See Armond Statement, supra note 406, at 10.
480 ANPRM, supra note 348, at 24514.
481 Id. at 24515.
482 Id. at 24516.
483 Id. at 24515–16.
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In the April 2024 NPRM on discretionary denial issues, USPTO did not propose rules concerning
parallel district court litigation. USPTO noted that it “continues to consider issuing proposed
rules” on issues raised in the ANPRM.484
The PREVAIL Act aims to “[e]nd duplicative patent challenges” that result from challengers
“raising the same or similar validity challenges” both at PTAB and in district court.485 Thus, the
“single forum” provision in the PREVAIL Act would prevent the petitioner, a real party in
interest, or a privy of the petitioner from maintaining a challenge to the validity of a patent on any
35 U.S.C. § 311(b) grounds (i.e., anticipation or obviousness in light of prior art patents and
printed publications) in a district court or ITC proceeding once an IPR is instituted on that
patent.486 Proponents argue that this change would “more closely align” PTAB’s practice with
“the policy goal of streamlining patent invalidity litigation and avoiding lengthy duplicate
invalidity disputes.”487 Some opponents argue that concerns about duplicative litigation would be
better addressed by legislation requiring parallel district court litigation to be stayed if an IPR is
instituted, since doing so could avoid costly district court litigation on patent claims that may be
invalidated.488
Patent Claims Already Upheld by a District Court
A final circumstance involves patents claims that have already been upheld as valid in district
court litigation. Currently, PTAB may choose to initiate or continue IPR proceedings after a
district court has already ruled on the validity of the patent at issue. One example involved a
patent owner that successfully sued Apple in district court for infringing its patents relating to
virtual private networks (VPNs).489 In 2014, the Federal Circuit upheld the district court’s
decision that the patents were valid.490 Two years later, however, PTAB found that the same
patents were invalid.491 This year, the Federal Circuit affirmed PTAB’s decision and vacated the
$576 million judgment against Apple. The Federal Circuit held this was consistent with its 2014
decision because PTAB is entitled to find invalidity under a more permissive “preponderance of
evidence” standard (as noted above).492
USPTO’s April 2023 ANPRM proposed changing PTAB’s practice such that PTAB would
generally deny petitions challenging claims that “substantially overlap” with claims that have
already been upheld by a “final adjudication” in district court.493 The ANPRM would have
provided an exception for petitioners who (1) either had standing to challenge the claims in
district court or intended to pursue commercialization of a product or service in the same field,
(2) were not a real party in interest or privy to the party previously challenging the claims unless

484 Discretionary Denial NPRM, supra note 348, at 28695.
485 PREVAIL ACT FACT SHEET, supra note 390, at 2.
486 See S. 2220, 118th Cong. § 4(c)(1)(C).
487 Armond Statement, supra note 406, at 10.
488 Matal Statement, supra note 395, at 15.
489 See VirnetX Inc. v. Cisco Sys., 767 F.3d 1308, 1313–14 (Fed. Cir. 2014).
490 See id. at 1324.
491 VirnetX Inc. v. Mangrove Partners Master Fund, Nos. 2020-2271, 2272, 2023 WL 2708975, at *3 (Fed. Cir. Mar.
30, 2023), cert. denied, No. 23-315, 2024 WL 674719 (U.S. Feb. 20, 2024).
492 Id. at *8 n.8.
493 ANPRM, supra note 348, at 24510 (noting finality would be defined consistent with 28 U.S.C. § 1295(a)(1)).
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the earlier petition was resolved for reasons not materially related to the merits, and (3) met a
higher burden of “compelling merits.”494
In the April 2024 NPRM on discretionary denial issues, USPTO did not propose rules concerning
patent claims already upheld by a district court. USPTO noted that it “continues to consider
issuing proposed rules” on issues raised in the ANPRM.495
The PREVAIL Act’s sponsors assert that instituting or maintaining PTAB proceedings following a
district court decision on validity leads to inefficiency and inconsistent decisions.496 Thus, the
PREVAIL Act would require PTAB to deny institution—as well as dismiss proceedings already in
progress—if a district court or the ITC has already entered a final judgment deciding a challenge
to the validity of the same patent claim on any Section 311(b) grounds in a case in which the
petitioner, a real party in interest, or a privy of the petitioner was a party.497 Opponents argue that
district courts are not an “adequate substitute” for PTAB review, given PTAB’s technical
expertise compared with district courts and juries,498 and thus that “district court validity
decisions are insufficiently reliable to serve as the final word on patent validity.”499
Conclusion
Since its creation in 2011, PTAB has become one of the more significant—and controversial—
aspects of the U.S. patent system. IPR, in particular, has become one of the most common ways
to determine the validity of issued patents. Patent law stakeholders thus often have strong views
on the procedural and substantive workings of PTAB and IPR. Current proposals for PTAB
include maintaining the tribunal as it exists, modifying IPR and PGR procedures, or abolishing
PTAB entirely. In weighing these options, Congress may consider whether the tribunal is
effectively serving its intended purpose of improving patent quality by providing an efficient
means of determining patent validity issues—or if, instead, AIA proceedings are unfair to patent
holders and create undue uncertainty in patent rights.

Author Information

Christopher T. Zirpoli
Kevin J. Hickey
Legislative Attorney
Legislative Attorney

494 ANRPM, supra note 348, at 23510.
495 Discretionary Denial NPRM, supra note 348, at 28695.
496 See PREVAIL ACT FACT SHEET, supra note 390, at 3.
497 See S. 2220, 118th Cong. § 4(c)(1)(G).
498 See Matal Statement, supra note 395, at 3–5.
499 Id. at 18.
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Congressional Research Service
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