United States Court of Appeals 

for the Federal Circuit ______________________

GILBERT P. HYATT,

Plaintiff-Cross-Appellant

v.

ANDREW HIRSHFELD, PERFORMING THE 

FUNCTIONS AND DUTIES OF THE UNDER

SECRETARY OF COMMERCE FOR 

INTELLECTUAL PROPERTY AND DIRECTOR OF 

THE UNITED STATES PATENT AND TRADEMARK 

OFFICE,

Defendant-Appellant

______________________

2018-2390, 2018-2391, 2018-2392, 2019-1038, 2019-1039, 

2019-1049, 2019-1070

______________________

Appeals from the United States District Court for the 

District of Columbia in Nos. 1:05-cv-02310-RCL, 1:09-cv01864-RCL, 1:09-cv-01869-RCL, 1:09-cv-01872-RCL, Senior Judge Royce C. Lamberth.

______________________

Decided: June 1, 2021

______________________

ANDREW M. GROSSMAN, Baker & Hostetler LLP, Washington, DC, argued for plaintiff-cross-appellant. Also represented by MARK W. DELAQUIL, JASON F. HOFFMAN. 

 THOMAS W. KRAUSE, Office of the Solicitor, United 

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2 HYATT v. HIRSHFELD

States Patent and Trademark Office, Alexandria, VA, argued for defendant-appellant. Also represented by ROBERT 

MCBRIDE, ROBERT J. MCMANUS, MOLLY R. SILFEN.

 ______________________

Before REYNA, WALLACH, and HUGHES, Circuit Judges.

REYNA, Circuit Judge.

The United States Patent and Trademark Office appeals a judgment of the United States District Court for the 

District of Columbia. Patent applicant Gilbert P. Hyatt 

filed an action under 35 U.S.C. § 145 against the Patent 

and Trademark Office to obtain four patents. The Patent 

and Trademark Office asserted affirmative defenses of 

prosecution laches and invalidity for anticipation and lack 

of written description. The district court first held a trial 

on prosecution laches and subsequently held trials on anticipation and written description. Following a Rule 52(c) 

motion at the first trial, the district court decided that the 

Patent and Trademark Office failed to carry its burden of 

proving prosecution laches. Following the patentability 

trials, the district court decided that certain claims were 

not invalid for anticipation or lack of written description 

and ordered the Patent and Trademark Office to issue patents as to those claims. 

We hold that prosecution laches is a defense available 

to the Patent and Trademark Office in an action to obtain 

a patent under 35 U.S.C. §145. We further hold that the 

district court erred in concluding that the Patent and 

Trademark Office had failed to prove prosecution laches. 

Accordingly, consistent with the principles of fairness and 

due process, we vacate and remand the district court’s decision on prosecution laches for further proceedings consistent with this opinion and to provide Hyatt the 

opportunity to present evidence on that issue. We hold the 

remainder of the case in abeyance, retaining jurisdiction 

over the anticipation and written description issues.

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HYATT v. HIRSHFELD 3

BACKGROUND

Submarine Patents

Prior to 1995, a patent’s term was measured as 17 

years from the date of issuance. See, e.g., Gilead Scis., Inc. 

v. Natco Pharma Ltd., 753 F.3d 1208, 1211 (Fed. Cir. 2014). 

The fact that patent term was keyed to the date of issuance, 

rather than the date of filing, incentivized certain patentees to delay prosecuting their patents by abandoning applications and filing continuing applications in their place. By 

doing so, patentees could obtain a patent at a financially 

desirable time when the accused product market had become suitably developed. See, e.g., Thomas J. Kowalski & 

Pamela G. Salkeld, The Impact of GATT on the United 

States Patent and Trademark Office, 11 ST. JOHN’S J.

LEGAL COMMENT. 455, 456 (1996) [hereinafter Kowalski]

(“Under the old law, United States patent applications 

could theoretically remain pending indefinitely through 

use of the ‘continuation’ procedure of refiling.”). This delay 

strategy has allowed some submarine patentees to specifically target competitors’ new products. Mark A. Lemley & 

Kimberly A. Moore, Ending Abuse of Patent Continuations, 

84 B.U. L. REV. 63, 76–78 (2004) [hereinafter Lemley]; see 

also Steve Blount & Louis S. Zarfas, The Use of Delaying 

Tactics to Obtain Submarine Patents and Amend Around a

Patent That a Competitor Has Designed Around, 81 J. PAT.

& TRADEMARK OFF. SOC’Y 11, 13, 28–30 (1999); John W. 

Schlicher, 2 Patent Law, Legal and Economic Principles 

§ 13:11 (2d ed. 2015) [hereinafter Schlicher]. Critics of this 

practice have argued that it harms industries by upsetting 

the expectations of product manufacturers who have invested in manufacturing facilities. See, e.g., Lemley, 84 

B.U. L. REV. at 80; see also Schlicher, 2 Patent Law, Legal 

and Economic Principles § 13:11. The ability to avoid publication of an application offers further opportunity for 

abuse because it deprives the public of timely disclosure, 

which is a central goal of the patent system. Lemley, 84 

B.U. L. REV. at 73.

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4 HYATT v. HIRSHFELD

Submarine patents have also added to the administrative burdens on the U.S. Patent and Trademark Office 

(“PTO”). Long chains of applications increase patent examiners’ caseloads, which have long tended to be large. 

See, e.g., Eugene R. Quinn, Jr., The Proliferation of Electronic Commerce Patents: Don’t Blame the PTO, 28 

RUTGERS COMPUTER & TECH. L.J. 121, 123 (2002) (stating 

that “patent examiners are simply too overworked” to weed 

out “patents that ought not see the light of day”); John R. 

Thomas, The Question Concerning Patent Law and Pioneer 

Inventions, 10 HIGH TECH. L.J. 35, 100 (1995) (stating that

examiners are “notoriously overworked”). Aware of this reality, some submarine patentees have employed the strategy of “wearing down” patent examiners over time and 

thereby obtaining a broader patent scope than warranted. 

See, e.g., Lemley, 84 B.U. L. REV. at 74–75. 

During negotiations of the Agreement on Trade-Related Aspects of Intellectual Property (“TRIPS Agreement”) at the Uruguay Round of the General Agreement on 

Tariff and Trade (“GATT”), the U.S. sought to address the 

problem of submarine patents by agreeing to change the

term of U.S. patents from 17 years following the date of 

issuance to 20 years following the filing date of the application or an earlier non-provisional application to which 

the subject application claims priority. TRIPS Agreement

art. 33, Apr. 15, 1994, Marrakesh Agreement Establishing 

the World Trade Organization, Annex 1C, 1869 U.N.T.S. 

299, 33 I.L.M. 1197, https://www.wto.org/english/docs_e/legal_e/27-trips.pdf. Congress then enacted this change in 

patent term into law. Uruguay Round Agreements Act, 

Pub. L. No. 103-465, § 532, 108 Stat. 4809, 4984 (1994) 

(amending 35 U.S.C. § 154 to provide a patent term of 20

years); see also Supernus Pharms., Inc. v. Iancu, 913 F.3d 

1351, 1353 (Fed. Cir. 2019). 

The U.S.’s change in patent term, which would become 

effective on June 8, 1995, triggered a patent application 

gold rush in the spring of 1995 often referred to as the 

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HYATT v. HIRSHFELD 5

“GATT Bubble.” See Hyatt v. Iancu, 332 F. Supp. 3d 113, 

122 (D.D.C. 2018) (“Iancu”); Kowalksi, 11 ST. JOHN’S J.

LEGAL COMMENT. at 456–57. Applicants filed a large number of applications in the short period before the change in 

patent term. For example, in the nine days leading to 

June 8, 1995, the PTO reported that it received and processed over 50,000 applications—one-quarter of the entire 

year’s projected filings. PTO Applications, 50 PAT.,

TRADEMARK & COPYRIGHT J. 253 (July 13, 1995). The influx 

from the GATT Bubble was so large that the PTO hired 

hundreds of patent examiners in 1995 and 1996 to process 

it. See Kowalski, 11 ST. JOHN’S J. LEGAL COMMENT. at 457. 

Hyatt’s Applications

As relevant to this appeal, Gilbert P. Hyatt is the 

named inventor on 399 patent applications, 381 of which 

he filed during the GATT Bubble. See Iancu, 

332 F. Supp. 3d at 118; J.A. 31859. Hyatt bulk-filed the 

381 applications, each one being a photocopy of one of 11

earlier parent applications. See, e.g., J.A. 29444, 31859, 

29407, 18944; Iancu, 332 F. Supp. 3d at 118. When filed, 

the applications contained small claim sets, many of which 

were identical to each other. See, e.g., J.A. 29444, 29406–

07. 

This appeal specifically involves four of Hyatt’s GATT 

Bubble applications: U.S. Patent Application 

No. 08/457,211 (“’211 application”), U.S. Patent Application No. 08/456,398 (“’398 application”), U.S. Patent Application No. 08/472,062 (“’062 application”), and U.S. Patent 

Application No. 08/431,639 (“’639 application”). These four 

applications relate to various computer technologies1 and 

claim priority to applications filed in the 1970s and 1980s, 

1 The specifics of the disclosed technologies do not 

materially affect this opinion.

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6 HYATT v. HIRSHFELD

which pre-date the applications by a range of 12 to 25

years.2 

Hyatt’s GATT Bubble applications, including the four 

at issue here, are atypically long and complex. According 

to PTO data, a typical patent application contains about 20 

to 30 pages. Iancu, 332 F. Supp. 3d at 124. In contrast, the 

’211 and ’398 applications have 576 pages of text and 65 

pages of figures; the ’062 patent includes 238 pages of text 

and 40 pages of figures; and the ’639 application includes 

518 pages of text and 46 pages of figures. Id. 

On October 24, 1995, about five months after Hyatt 

filed his GATT Bubble applications, PTO group Director 

Nicholas Godici met with Hyatt to discuss the applications. 

Director Godici asked Hyatt, and Hyatt agreed, to focus 

each application’s claims on distinct subject matter. Id. at 

128. Neither party memorialized the agreement at the 

time, but neither party disputes that it occurred. Id.; 

J.A. 41516, 29348 ll. 3–14. 

Between that meeting and 2003, Hyatt filed a series of 

amendments in his applications that grew the number of 

claims to a total of approximately 115,000, including approximately 45,000 independent claims. See, e.g., 

J.A. 38154, 38161–62, 29555, 29444; Iancu, 332 F. Supp. 

2 The ’211 application was filed on June 1, 1995, and 

claims priority to an application filed 12 years earlier in 

1983. J.A. 7606–07, 8705, 14397–98. The ’398 application

was filed on June 1, 1995, shares the same specification as 

the ’211 application, and claims priority to the same 1983 

application. J.A. 8705, 14397–98, 14560. The ’062 application was filed on June 6, 1995, and claims priority to an 

application filed 20 years earlier in 1975. J.A. 16071–73, 

16453. The ’639 application was filed on May 1, 1995, and 

claims priority to an application filed 25 years earlier in 

1970. J.A. 18097–101. 

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HYATT v. HIRSHFELD 7

3d at 124. Hyatt’s GATT Bubble applications therefore 

eventually contained, on average, 300 claims per application, which far exceeded the average number of claims in 

applications pending before the PTO. See Iancu, 332 

F. Supp. 3d at 124. The four specific applications at issue 

here included a total of 1,592 claims, i.e., an average of 398 

claims per application. See id. 

Mr. Hyatt’s claim amendments adding hundreds of 

claims per application on average meant that Hyatt had

presented claims for examination between 12 and 28 years 

after their alleged priority dates. Specifically, Mr. Hyatt 

waited from 25 to 28 years to present his claims in the ’639 

application, J.A. 18614–56, 18033–41, 17976–8022, 17889–

947, 17707–832; 12 to 16 years to present those in the ’211 

application, J.A 9281–89, 8018–40, 7983–8015, 7825–49, 

7640–719, 7539–93, 7019–111; 12 to 20 years to present 

those in the ’398 application, J.A. 15210–19, 14536–58, 

14317–96, 14288–314, 14257–85, 14118–204, 13574–685, 

13520–49, 47748; and 20 to 21 years to present those in the 

’062 application, J.A. 16690–95, 16367–97, 16330–37, 

16243–314. For these many years, Mr. Hyatt’s inventions 

were submerged. 

From 2003 to 2012, the PTO stayed the examination of 

many of Hyatt’s applications pending litigation. Hyatt’s 

applications have been involved in various cases before the 

federal courts whose outcomes were likely to affect PTO’s 

handling of most or all of his other applications.3 See

3 Hyatt’s lawsuits have addressed a variety of issues, 

such as challenging examiners’ written description rejections, Hyatt v. Dudas, 492 F.3d 1365 (Fed. Cir. 2007); challenging the PTO’s ability to use representative claims in 

Board decisions, Hyatt v. Dudas, 551 F.3d 1307 (Fed. Cir. 

2008); and challenging the PTO’s position that plaintiffs in 

§ 145 actions may present new evidence only if it had no 

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8 HYATT v. HIRSHFELD

J.A. 18944; Hyatt v. USPTO, No. 1:13-CV-1535, 2014 WL 

2446176, at *1 (E.D. Va. May 29, 2014). 

The PTO’s Requirements

In 2013, the PTO resumed examination of Hyatt’s applications. Around that time the PTO created an art unit, 

comprised originally of 12 experienced examiners, dedicated to examining Hyatt’s applications. See Iancu, 

332 F. Supp. 3d at 119; J.A. 29366, 29567–68. Initially the 

examiners took a compact prosecution approach, in which 

they prepared a fulsome set of rejections on the first office 

action so that the next action might become final. J.A. 

29433, 29569. The examiners took approximately four to 

five months to write their first office actions, each of which

spanned hundreds of pages. See, e.g., J.A. 29567–69, 38187 

n.7. In contrast, a typical examination took 20 hours, or 

two to three business days, of examiner time. J.A. 29570. 

To facilitate the examination process, from August to 

October 2013, the PTO issued 11 notifications to Hyatt 

called “Requirements.” See, e.g., J.A. 31856–96, 32885–

923, 33585–645, 33646–73, 36310–47, 36565–93, 36705–

38, 37031–69, 37837–72, 38094–150, 38151–96. Each Requirement corresponded to a set of applications that shared 

a common specification belonging to one of the GATT Bubble applications’ 11 parent applications. See, e.g., 

J.A. 31860–62. These Requirements were designed to solicit information from Mr. Hyatt that would streamline 

prosecution of his applications. 

The PTO first described the challenges that Hyatt’s applications had created. For example, the PTO could not 

reasonably ascertain the priority dates of the claimed inventions because the applications claimed priority to numerous applications. See, e.g., J.A. 31863–64 (listing the 

reasonable opportunity to present it to the PTO in the first 

instance, Kappos v. Hyatt, 566 U.S. 431 (2012).

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HYATT v. HIRSHFELD 9

43 applications filed from 1969 to 1983 to which one group 

of applications claimed priority). The length of the applications, as well as the length of the priority applications,

also hindered examiners’ ability to determine compliance 

with 35 U.S.C. § 112. See, e.g., J.A. 31865–66. The PTO 

further explained that the number of claims, and their multiplication through amendments since 1995, also posed a 

significant hurdle to processing the applications. See, e.g., 

J.A. 31869–72. The PTO also pointed out a large amount

of repetition and redundancy of claims across applications. 

J.A. 31872–85. Because of these factors, the PTO estimated it would take 532 years of examiner time at its thencurrent rate to process Hyatt’s applications. J.A. 31886 & 

n.14. The PTO therefore instructed Hyatt to (i) select no 

more than 600 total claims to pursue for each of the 11

specifications; (ii) identify the priority date and support for 

that date with respect to each chosen claim; and (iii) submit 

a clean copy of the claims. See, e.g., J.A. 31888–91. 

Examination and Review by the Board

The four Hyatt applications’ claims were finally rejected and reviewed on appeal by the Board of Patent Appeals and Interferences (“Board”), which affirmed

rejections of certain claims in each application. Iancu, 

332 F. Supp. 3d at 124–26. Specifically, during examination of the ’639 application, an examiner rejected all pending claims for lack of written description or obviousness. 

J.A. 626–27. The Board affirmed in part and reversed in 

part, placing some claims in condition for allowance. 

J.A. 715–16. On rehearing, the Board withdrew only certain additional rejections. J.A. 762. 

During examination of the ’211 application, an examiner rejected all but a small number of claims for lack of 

written description, lack of enablement, and obviousness, 

and the Board reversed certain non-enablement and obviousness rejections. J.A. 207, 213, 262–63. On rehearing, 

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10 HYATT v. HIRSHFELD

the Board denied Hyatt’s request to withdraw additional 

rejections. J.A. 280. 

Further, an examiner rejected all claims in the ’398 application for lack of written description and some of those 

claims for obviousness or anticipation. J.A. 285. The 

Board affirmed in part and found a new ground for rejection under § 101. J.A. 286, 383–84. On rehearing, the 

Board withdrew certain additional written description and 

prior art-based rejections. J.A. 554. 

As for the ’062 application, an examiner rejected all 

claims for lack of written description and enablement, as 

well as for obviousness-type double patenting. J.A. 557, 

564. The Board affirmed certain § 112 rejections and the 

double patenting rejection for one claim and reversed rejections as to other claims. J.A. 601. On rehearing, the Board 

withdrew its written description rejection with respect to 

one claim. J.A. 624.

Hyatt’s § 145 Actions

On November 18, 2005, Hyatt filed a § 145 action4 in 

the U.S. District Court for the District of Columbia seeking 

issuance of a patent from the ’211 application. J.A. 60284–

4 An applicant may appeal an adverse decision by 

the Board directly to this court or may file a civil action in 

district court under 35 U.S.C. § 145 to obtain a patent. 

35 U.S.C. § 145; Hyatt v. Kappos, 625 F.3d 1320, 1322 (Fed. 

Cir. 2010), overruled on other grounds by Kappos v. Hyatt, 

566 U.S. 431 (2012). We have explained that the § 145 action is a hybrid action. Hyatt, 625 F.3d at 1322. It is unlike 

an appeal because the plaintiff can present new evidence. 

Id. However, if the applicant presents no new evidence, 

then the district court reviews the action on the administrative record, id., and the district court reviews de novo 

any issue for which the applicant presents new evidence, 

id. at 1336.

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HYATT v. HIRSHFELD 11

89. On September 25, 2009, he filed three additional § 145

actions in the same court with respect to the ’398, ’062, and 

’639 applications. J.A. 60291–304. In each complaint, Hyatt alleged that the PTO had made factual errors and failed 

to comply with the law in refusing to issue patents from 

these applications. See J.A. 60284–304.

On August 23, 2016, the district court issued a series 

of orders on the parties’ motions for summary judgment. 

The court denied Hyatt’s motions, and granted the PTO’s 

motions in part. J.A. 195, 47210–11, 55447–70, 56065–82. 

The district court explained that factual issues precluded 

summary judgment on certain issues, including written description, anticipation, and obviousness-type double patenting. J.A. 55449–70, 56067–82. 

The next month, the PTO filed a motion to dismiss each 

case on prosecution laches grounds. Iancu, 332 F. Supp. 3d 

at 117–18; J.A. 134–35, 155–56, 176–77, 196–97, 18891–

941. The PTO argued that Hyatt had engaged in a “pattern

of delay in prosecuting his nearly 400 patent applications 

from 1969 through the present day.” J.A. 18902. According to the PTO, that was true even disregarding the period 

from 2003 to 2012—which the PTO did not rely on—when

the PTO suspended prosecution of most of Hyatt’s applications due to pending litigation. Iancu, 332 F. Supp. 3d at 

124, 129, 133 n.14. The PTO argued that Hyatt forfeited 

his patent rights by, for example, claiming priority to applications more than 45 years old; bulk-filing about 400 

photocopies of 11 applications in the days before the U.S.’s 

patent term changed on June 8, 1995; and agreeing to focus 

each application on a different invention but not doing so 

and later revealing that he never had a “master plan” for 

demarcating the applications. Id. at 117–18. 

Hyatt responded that his prosecution of applications 

other than the four at issue was legally irrelevant; that the 

PTO itself engaged in extensive delays in administering his

applications; that the PTO did not warn him, as allegedly 

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12 HYATT v. HIRSHFELD

required, that he was in jeopardy of losing his patent 

rights; and that the PTO failed to prove intervening rights 

as necessary to establish prosecution laches. J.A. 19289.

Hyatt also argued that his delays were explainable because, for example, PTO rules permitted Hyatt to add and 

amend claims, and Hyatt did so to correctly capture his inventions and steer clear of prior art. See, e.g., Pl.’s Opp. to 

Def.’s Mot. to Dismiss for Prosecution Laches at 10, Hyatt 

v. Matal, No. 1:05-cv-02310-RCL (D.D.C. Jan. 9, 2017), 

ECF No. 101.5 The court treated the PTO’s motions to dismiss as motions for summary judgment and denied them 

because genuine issues of material fact existed. Iancu, 332 

F. Supp. 3d at 118. 

In October 2017, the district court held a five-day, consolidated bench trial on whether prosecution laches barred 

the issuance of patents from the ’211, ’398, ’062, and ’639 

applications. Id. The PTO presented three witnesses: 

(i) Robert Clarke; (ii) Gregory Morse; and (iii) Stephen Kunin. Id. at 118–19. 

Mr. Clarke testified on behalf of the PTO about its patent examination procedures. Mr. Clarke served as the editor of the Manual of Patent Examining Procedure 

(“MPEP”) and had previously held other high-level positions at the PTO, including Chief of Staff and Director of 

the Office of Patent and Legal Administration. J.A. 29185. 

He testified, for example, that Director Godici met with Hyatt on October 24, 1995, and asked Hyatt to demarcate his 

applications. See J.A. 29348, 41516. Mr. Clarke further 

testified that the PTO’s practice is to bring prosecution to 

a close as quickly as possible. J.A. 29320. He also testified 

5 Hyatt filed apparently identical oppositions in the 

other three cases, No. 1:09-cv-01864-RCL (regarding the 

’398 application); No. 1:09-cv-01872-RCL (regarding the 

’639 application); and No. 1:09-cv-01869-RCL (regarding 

the ’062 application). 

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HYATT v. HIRSHFELD 13

that “it’s possible” that the PTO could have devoted more 

resources to Hyatt’s applications. J.A. 29320–21. 

Mr. Morse served as the supervisor of Group Art Unit 

2615, the unit dedicated to Hyatt’s applications. J.A. 

29363–64; Iancu, 332 F. Supp. 3d. at 119. Mr. Morse’s testimony focused on the history and nature of Hyatt’s applications, the unique challenges they posed to the PTO, and 

the PTO’s handling of the applications. See, e.g., J.A. 

29363–67, 29399–486, 29543–620, 29639–50, 29657, 

29807, 29823. According to Mr. Morse, the complexity, 

number, size, and overlap of Hyatt’s applications and 

claims made it difficult, if not impossible, for examiners to 

determine the claims’ priority dates for purposes of identifying the relevant body of prior art, to determine whether 

the claims satisfy the written description requirement, and 

to identify double patenting issues. See, e.g., J.A. 29368, 

29417–26, 18944. Further complicating the examiners’ 

task was their need to find not only disclosures of individual claim elements, but more specifically disclosures of interconnections between those elements. J.A. 29435–36. 

Hyatt’s tendency to rewrite claims in whole or in significant part midway through prosecution effectively restarted 

prosecution for the newly rewritten claims. J.A. 29464–66, 

19471–72. When asked whether Hyatt had been forthcoming about priority dates before the PTO issued its Requirements in the fall of 2013, Mr. Morse responded, “No. That 

has been a persistent issue across this entire family of applications.” J.A. 29429. 

Mr. Kunin testified as an expert witness regarding the 

PTO’s patent policy, practice, and procedure. Mr. Kunin

opined, in summary, that “Mr. Hyatt’s pattern of conduct 

unreasonably and unexplainably delayed prosecution, resulting in needlessly increased examiner time and its associated costs to the USPTO to conclude examination of his 

applications.” J.A. 39235–83; see also J.A. 30200, 29990. 

Mr. Kunin pointed to several factors in support. For example, Hyatt had delayed years and sometimes multiple 

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14 HYATT v. HIRSHFELD

decades after his alleged priority dates to submit claims. 

J.A. 30201. According to Mr. Kunin, unreasonable and unexplainable delay also resulted from Hyatt’s pattern of conduct during prosecution, including (i) dramatically

increasing, i.e., unduly multiplying, the number of claims6

contrary to 37 C.F.R. 1.75(b); (ii) rewriting, i.e., shifting, 

claims in large portions or in their entirety contrary to 

37 C.F.R. § 1.145; (iii) presenting numerous duplicate or 

patentably indistinct claims across applications without informing the PTO contrary to MPEP §§ 2001.06(b), 2004(9); 

and (iv) failing to identify written description support for 

claims contrary to MPEP §§ 714.02, 2163.06. See, e.g., J.A. 

30201; see also J.A. 39238. Mr. Kunin pointed to additional 

specific instances of prosecution conduct that evinced the 

unreasonableness of Hyatt’s prosecution conduct, namely 

(i) filing claims that Hyatt had already lost in interference 

proceedings without informing the examiner; (ii) failing to 

take allowed claims but rather refiling them years after 

their allowance in a separate application; and (iii) failing 

to prosecute district court actions under § 145. See, e.g., 

J.A. 30202. 

At the close of the PTO’s case-in-chief on prosecution 

laches, Hyatt moved for judgment on partial findings pursuant to Rule 52(c) of the Federal Rules of Civil Procedure.7 

Iancu, 332 F. Supp. 3d at 119. Hyatt argued that the PTO 

6 Mr. Kunin also testified that fewer than 0.02% of 

all applications filed from 1995 to 2013 included 299 or 

more claims. J.A. 39243.

7 Rule 52(c) provides that, in a nonjury trial, if a 

party has been fully heard on an issue and the court finds 

against the party on that issue, “the court may enter judgment against the party on a claim or defense that, under 

the controlling law, can be maintained or defeated only 

with a favorable finding on that issue.” FED. R. CIV. P. 

52(c).

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HYATT v. HIRSHFELD 15

failed to prove prosecution laches because the PTO (i) did 

not show it provided Hyatt with adequate warnings of 

laches rejections; (ii) did not prove intervening rights; 

(iii) never issued laches rejections for the four applications 

at issue; and (iv) failed to meet its burden of proving unreasonable and unexplained delay by a preponderance of 

the evidence. Id.

In the months following the prosecution laches trial, 

the district court conducted additional bench trials on the 

patentability of the four applications’ claims. See J.A. 140–

43, 160–63, 182–83, 202–04. 

The District Court’s Decisions

On August 1, 2018, the district court issued a series of 

orders resolving the issues in the four cases. First, it dismissed the case with respect to the ’062 application because 

the parties no longer disputed claim 45, the only claim that 

remained after the court’s summary judgment orders. 

J.A. 120. 

The court issued a separate order pursuant to 

Rule 52(c) of the Federal Rules of Civil Procedure concluding that prosecution laches did not bar issuance of patents 

from the ’211, ’398, ’062, and ’639 applications. See Iancu, 

332 F. Supp. 3d at 131, 138. The central thrust of the district court’s analysis was that the PTO had failed to take 

the actions necessary to advance the prosecution of Hyatt’s 

applications. See id. at 131–38. At the outset, the court 

explained that it would only consider delay up to 2002 in 

its analysis because (i) the PTO “shoulders responsibility” 

for suspending prosecution of Hyatt’s applications pending 

litigation from 2003 to 2012, and (ii) after 2012, the relevance of Hyatt’s delays in prosecuting applications other 

than the four at issue “is so circumspect that the [c]ourt 

must decline to consider it here.” Id. at 131–32. 

The district court reasoned that the uniqueness of Hyatt’s voluminous applications “required [the PTO] to 

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16 HYATT v. HIRSHFELD

employ and embrace atypical procedures for addressing” 

his applications. See id. at 133. The court faulted the PTO 

for trying to “fit the large proverbial square peg of Hyatt’s 

applications into the rounded-out and well-trodden hole of 

its 3,000 page practice manual.” Id. According to the court, 

the PTO’s refusal to adopt “atypical procedures” made a 

finding of prosecution laches “[un]warrant[ed].” Id. 

The district court then found the PTO’s efforts to advance prosecution—including the October 1995 meeting 

between Hyatt and Director Godici—were so informal and 

inadequate as to preclude a finding of prosecution laches. 

Id. at 134–37. The court faulted the PTO for not using “specific and formal” measures up to 2002 to obtain the information it needed from Hyatt to successfully administer his 

applications. Id. at 134. According to the court, the PTO 

should have used formal measures “rather than await Mr. 

Hyatt’s help, which, it appears obvious, was not forthcoming.” Id. The court stated that “it would seem to have been 

in Mr. Hyatt’s interest to assist examination when invited 

to do so, if he had indeed prioritized having his applied-for 

patents issue at the earliest possible date.” Id. The court 

further found that the PTO’s non-use of more formal 

measures to seek information and amendments deprived 

Hyatt of an “opportunity to amend or cancel claims to avoid 

rejections.” Id. at 134–35. If the PTO had used such 

measures, the court reasoned, “[i]t is entirely likely that 

Mr. Hyatt could have been more helpful during the examination process.” Id. at 135 (quotation omitted). The court 

explained that it was “left with no choice but to conclude 

that the PTO itself ignored for 20 years the details of whatever informal agreement Mr. Hyatt and Mr. Godici had.” 

Id. The PTO “cannot have it both ways here,” the court 

explained, by “lament[ing] decades of allegedly outrageous 

conduct” while arguing its own inaction is irrelevant. Id.

at 136. 

The district court made various additional determinations in a section at the end of its order titled “Other 

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HYATT v. HIRSHFELD 17

Matters.” Id. at 137. First, the district court assigned little 

weight to the fact that the PTO spent more than $10 million in the last five years examining claims in Hyatt’s 

GATT Bubble applications whereas Mr. Hyatt had only 

paid about $7 million in fees. Id. 

Second, the court concluded that Mr. Hyatt’s “claim 

shifting”—or amending claims so significantly “as to effectively create a new claim”—did not warrant a finding of 

prosecution laches. Id. at 137–38. The district court again 

faulted the PTO for “accept[ing] the amendments and continu[ing] examination” in such cases. Id. at 137. The court 

“appreciate[d] the challenge that faced the PTO in processing these unusual applications,” but nevertheless 

stated it could not bar the patents for prosecution laches 

because “the PTO itself did nothing to police the conduct 

they now complain of for the better part of two decades.” 

Id. 

The court next found insufficient the PTO’s evidence 

that Hyatt had re-introduced claims in the applications at 

issue even though he had previously lost them in interference proceedings. Id. at 138. The court found Hyatt’s conduct “was not reasonable,” and that the PTO is entitled to 

assume that an application is not claiming an invention he 

already lost. Id. But nevertheless, the court reasoned, Hyatt’s “unreasonable conduct as to four allegedly illustrative 

claims does very little to move the ball in consideration of 

the totality of Mr. Hyatt's conduct across approximately 

115,000 claims.” Id. 

That same day, August 1, 2018, the district court issued another order addressing the patentability of the four 

applications’ claims at issue. See J.A. 71–113, 144, 165, 

184, 205. The court concluded certain claims in the ’211, 

’398, and ’639 applications met the written description, 

non-obviousness and novelty requirements for patentability and ordered the PTO to issue patents for those claims. 

See id. at 85–113. 

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18 HYATT v. HIRSHFELD

The PTO appeals the district court’s decision on prosecution laches, written description, and novelty, and challenges the district court’s authority to order the PTO to 

issue a patent. See Appellant’s Br. 5–6. Hyatt cross-appeals the district court’s decision not to enter judgment on 

claims for which the Board reversed the examiner’s rejections and that the PTO failed to dispute in court. Appellee’s Br. 87–88. We have jurisdiction under 28 U.S.C. 

§ 1295(a)(4).

STANDARD OF REVIEW

We review the district court’s factual findings for clear 

error and its legal conclusions de novo. Intellectual Ventures I LLC v. Symantec Corp., 838 F.3d 1307, 1312 (Fed. 

Cir. 2016). We review a district court’s determination of 

prosecution laches for abuse of discretion. Cancer Research 

Tech. Ltd. v. Barr Lab’ys Inc., 625 F.3d 724, 728–29 (Fed. 

Cir. 2010). “‘We may find an abuse of discretion on a showing that the court . . . exercised its discretion based upon 

an error of law or clearly erroneous factual findings.’” SiOnyx LLC v. Hamamatsu Photonics K.K., 981 F.3d 1339, 

1349 (Fed. Cir. 2020) (quoting Innogenetics, N.V. v. Abbott 

Lab’ys, 512 F.3d 1363, 1379 (Fed. Cir. 2008)).

DISCUSSION

Prosecution Laches

A

The doctrine of laches is an equitable affirmative defense. Cancer Research, 625 F.3d at 728. Prosecution 

laches may “render a patent unenforceable when it has issued only after an unreasonable and unexplained delay in 

prosecution that constitutes an egregious misuse of the 

statutory patent system under a totality of the circumstances.” Id. (quotation and citation omitted). Finding an 

unreasonable and unexplained delay in prosecution “includes a finding of prejudice[.]” Id. at 729.

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HYATT v. HIRSHFELD 19

The prosecution laches defense originates from two Supreme Court cases in the early 1900s. See Woodbridge v. 

United States, 263 U.S. 50 (1923); Webster Elec. Co. v. 

Splitdorf Elec. Co., 264 U.S. 463 (1924). In Woodbridge, 

the Court applied the doctrine to render a patent unenforceable based on a nine-year delay in prosecution.

263 U.S. at 53. The PTO had agreed with Woodbridge’s request to delay the issuance of his patent for one year. Id.

at 52. At the end of the year, the PTO neglected to issue 

the patent. Id. at 53. Woodbridge waited an additional 

eight-and-a-half years before sending a letter to the PTO 

calling attention to the application and explaining that he 

had waited because the delay enabled him to best avail 

himself of the patent’s value. Id. He then sought to amend 

the specification and claims to capture related innovations 

that arose during the course of the delay. Id. The Court 

held that, by delaying to “mak[e] the term of the monopoly 

square with the period when the commercial profit from it 

would have been highest,” Woodbridge “forfeit[ed] the right 

to a patent by designed delay.” Id. at 56. The Court reasoned that 

[a]ny practice by the inventor and applicant for a 

patent through which he deliberately and without 

excuse postpones beyond the date of the actual invention, the beginning of the term of his monopoly, 

and thus puts off the free public enjoyment of the 

useful invention, is an evasion of the statute and 

defeats its benevolent aim.

Id. at 56. 

The next year, in Webster Electric, the Court similarly

held that an unreasonable delay of eight years rendered a 

patent unenforceable. 264 U.S. at 465, 471. The applicant 

filed a patent application in 1910. Id. at 464. In 1915, to 

provoke an interference against a separate, recently issued

patent, the applicant filed a divisional application copying 

the patent’s claims. Id. The applicant lost the interference 

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20 HYATT v. HIRSHFELD

and then amended the divisional application by adding two 

new claims, claims 7 and 8, which issued in 1918 and were 

the subject of the litigation. Id. at 464–65. The Court explained that it was not until 1918 that the applicant intended to assert claims 7 and 8, which were broader than 

any he previously sought. Id. at 465–66. Meanwhile, 

“[d]uring all of this time the subject matter was disclosed 

and in general use, and [the applicant] and his assignee, so 

far as claims 7 and 8 are concerned, simply stood by and 

awaited developments.” Id. at 465. The Court held claims 

7 and 8 unenforceable, noting it had “no hesitation in saying that the delay was unreasonable, and, under the circumstances shown by the record, constitutes laches, by 

which the petitioner lost whatever rights it might otherwise have been entitled to.” Id. at 466. 

We have observed that, in enacting the Patent Act of 

1952, Congress intended the prosecution laches defense to 

remain available. Symbol Techs., Inc. v. Lemelson Med., 

Educ. & Research Found., LP, 277 F.3d 1361, 1365–66 

(Fed. Cir. 2002). P.J. Federico, an original drafter of the 

Act, explained in a renowned series of lectures following 

the Act’s enactment that § 282 incorporated the defenses to 

infringement that were available at that time, including 

laches, such that they remained available to accused infringers. Pub. L. No. 82-593, 66 Stat. 792, 812; see also 

35 U.S.C. § 282; P.J. Federico, Commentary on the New Patent Act (West 1954), reprinted in 75 J. PAT. & TRADEMARK 

OFF. SOC’Y 161, 215 (1993) (referring to defenses that may 

be raised in an action involving the validity or infringement of a patent and stating “this would include . . . equitable defenses such as laches, estoppel, and unclean 

hands”).

Nearly eighty years after Webster Electric, we confirmed that prosecution laches, as a matter of law, is an 

available defense to patent infringement. Symbol Techs.,

277 F.3d at 1363, 1366–68. Soon after that we applied the 

doctrine for the first time, concluding that a patentee had 

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HYATT v. HIRSHFELD 21

forfeited his right to a patent. In re Bogese, 303 F.3d 1362, 

1363 (Fed. Cir. 2002). In Bogese, between 1987 and 1995, 

the applicant engaged in “deliberate and consistent course 

of conduct that has resulted in an exceptional delay in advancing the prosecution and the issuance of a patent.” Id.

at 1365. Specifically, he filed 12 continuation applications

without amendment or addressing the reasons for the rejection and each time abandoned the previous application. 

Id. at 1363–65. The patent examiner ultimately rejected 

all pending claims on the grounds that the applicant’s actions “deliberately postponed meaningful prosecution, deliberately postponed the grant of any patent to which he 

may be entitled, and deliberately postponed the free public 

enjoyment” of the claimed inventions, evading the patent 

statute and defeating its benevolent aim. Id. at 1365. 

On review, the Board agreed with the examiner’s decision, calling the applicant’s actions “so egregious in defeating the policy of the patent laws of promoting science and 

the useful arts as to be presumed unreasonable.” Id. at 

1366. The harm caused by the applicant, the Board explained, was not only the delayed disclosure of his invention, but also the “deliberate delay of the term of any 

monopoly granted by a patent” until a time “when the industry has developed and matured to such a point as to be 

more financially beneficial to the applicant and hence more 

harmful or prejudicial to the public.” Id. 

Bogese appealed to this court, challenging the PTO’s 

exercise of authority to require him to advance the prosecution of his patent application. Id. at 1369. We held that 

that the PTO’s sanction for undue delay under the doctrine 

of prosecution laches was not arbitrary, capricious, or contrary to law under the Administrative Procedure Act, 

5 U.S.C. § 706. Id. at 1366–69.

Since Bogese, we have affirmed a prosecution laches determination one other time. See Symbol Techs., Inc. v. 

Lemelson Med., Educ. & Research Found., LP, 422 

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22 HYATT v. HIRSHFELD

F.3d 1378, 1385 (Fed. Cir. 2005) (“Symbol Technologies

II”). In Symbol Technologies II, the patentee’s delays resulted in 18- to 39-year time periods between the filing of 

applications to the issuance of the patents in suit. See id.

at 1386. The district court found that the patentee’s patents ranked in the “‘top thirteen positions’ for the longest 

prosecutions” for the period from 1914 to 2001. Id. (citation 

omitted). On appeal, we explained that this type of delay 

“is not what is contemplated by the patent statute when it 

provides for continuation and continuation-in-part applications,” and that such delay creates an “adverse effect on 

businesses that [are] unable to determine what [is] patented from what [is] not patented.” Id. 

In Symbol Technologies II, we provided examples of 

both reasonable and unreasonable delay. Id. at 1385. 

Three examples of reasonable delay include: (i) filing a divisional application in response to a restriction requirement, even if the filing occurs immediately before issuance 

of the parent application; (ii) refiling an application to present new evidence of an invention’s unexpected advantages; and (iii) refiling an application “to add subject 

matter in order to attempt to support broader claims as the 

development of an invention progresses.” Id. We clarified 

that these examples are not exhaustive and that an applicant could reasonably refile an application where that refiling “is not unduly successive or repetitive.” Id. 

In contrast, we explained, unreasonable delays involve

repetitive refilings that demonstrate unjustifiable prosecution delay, for example, “refiling an application solely containing previously-allowed claims for the business purpose 

of delaying their issuance.” Id. (citations omitted). We reasoned that the determination of unreasonable delay is not 

limited to the circumstances surrounding the particular 

application at issue; instead, “an examination of the totality of the circumstances, including the prosecution history 

of all of a series of related patents and overall delay in issuing claims, may trigger laches.” Id. at 1385–86.

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HYATT v. HIRSHFELD 23

In Cancer Research Technology Ltd. v. Barr Laboratories, Inc., we expanded the requirements for prevailing on 

a prosecution laches defense to infringement. 625 F.3d 724 

(Fed. Cir. 2010). Specifically, we held that prosecution 

laches requires proving two elements: (a) that the patentee’s delay in prosecution was unreasonable and inexcusable under the totality of circumstances, and (b) that 

the accused infringer suffered prejudice attributable to the 

delay. Id. at 728–29. To establish prejudice, we explained, 

an accused infringer must show evidence of intervening 

rights, that is, that the accused infringer or others “invested in, worked on, or used the claimed technology during the period of delay.”8 Id. at 729. Because the defendant 

had not proven prejudice, we reversed the district court’s 

judgment that the patent at issue was unenforceable for 

prosecution laches. Id. at 726, 731–32. 

Although Woodbridge, Webster Electric, Bogese, Symbol Technologies II, and Cancer Research provide guidance

on the application of laches in certain circumstances, we

now address for the first time the PTO’s assertion of a prosecution laches defense in a civil action brought by a patentee under 35 U.S.C. § 145 to obtain a patent.

B

Before turning to the merits of prosecution laches, we

address the threshold issue of whether the PTO can assert 

the defense of prosecution laches in a § 145 action. We hold 

that it can. As we have explained, the PTO has the authority to deny patent issuance on prosecution laches grounds. 

Bogese, 303 F.3d at 1367 (“It necessarily follows that the 

PTO has the authority to reject patent applications for patents that would be unenforceable” for prosecution laches.). 

8 See, e.g., John Bean Techs. Corp. v. Morris & Assocs., Inc., 988 F.3d 1334, 1338 (Fed. Cir. 2021) (discussing 

intervening rights).

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24 HYATT v. HIRSHFELD

The PTO also has the right to defend, in appeals before this 

court, its rejections of patent claims based on prosecution 

laches. See id. Further, the language of § 282 demonstrates Congress’s desire to make affirmative defenses, including equitable ones such as prosecution laches, broadly 

available. See 35 U.S.C. § 282 (making available affirmative defenses, including “any other fact or act made a defense by this title,” “in any action involving” patent 

validity); P.J. Federico, Commentary on the New Patent Act

(West 1954), reprinted in 75 J. PAT. & TRADEMARK OFF.

SOC’Y 161, 215 (1993) (explaining that Congress intended 

to incorporate equitable defenses including laches into the 

Patent Act of 1952). Defendants may accordingly assert 

the prosecution laches defense in district court infringement cases. See Symbol Techs., 277 F. 3d at 1363. These 

factors point to the conclusion that the PTO should be permitted to assert the prosecution laches defense in a § 145 

action. In our view it would make little sense for the PTO 

to have the authority to use prosecution laches as a basis 

for denying a patent, but to lack the authority to defend 

against issuance of a patent in a § 145 action on the same 

basis. Hyatt articulates no principled reason why we 

should adopt such an approach, and we are not otherwise 

aware of one. 

Further, the PTO may assert the prosecution laches defense in a § 145 action even if it did not previously issue 

rejections based on, or warnings regarding, prosecution 

laches during the prosecution of an application that is at 

issue in the § 145 action. In Kappos v. Hyatt, the Supreme 

Court concluded that “there are no limitations on a patent 

applicant’s ability to introduce new evidence in a § 145 proceeding beyond those already present in the Federal Rules 

of Evidence and the Federal Rules of Civil Procedure.” 566 

U.S. 431, 445–46 (2012). Following Kappos, we held that 

new evidence may be admitted “without regard to whether 

the issue was raised before the Board.” Troy v. Samson 

Mfg. Corp., 758 F.3d 1322, 1325 (Fed. Cir. 2014). Under 

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HYATT v. HIRSHFELD 25

these holdings, § 145 actions open the door to new evidence 

and arguments. Fairness dictates that the door must also 

remain open for the PTO to assert its meritorious defenses 

under the circumstances, including prosecution laches. 

Moreover, reserving the prosecution laches determination 

for infringement actions, but not § 145 actions, would harm 

the public’s interest by allowing a patentee to enforce a patent that could have been barred for prosecution laches in 

an earlier § 145 action. While the PTO’s failure to previously warn the applicant or reject claims based on prosecution laches may be considered as part of the totality of the 

circumstances in determining prosecution laches, it does 

not bar the PTO from asserting the defense in a § 145 action. 

C

We turn next to the district court’s decision on prosecution laches. We conclude that the district court misapplied 

the legal standard for prosecution laches in several respects. We address each in turn. 

Totality of the Circumstances

The district court failed to properly consider the totality of the circumstances. The court stated that “th[e] totality principle does not apply in a manner as to require this

Court to account for the entirety of the prosecution history 

of each related application from its inception to final disposition.” Iancu, 332 F. Supp. 3d at 131. The district court 

then focused predominantly on the PTO’s role in the prosecution of Hyatt’s four applications at issue and repeatedly 

discounted or ignored evidence showing that Hyatt’s conduct caused unreasonable and unexplained delay. See 

Iancu, 332 F. Supp. 3d at 122–39. 

For example, the district court ignored evidence of Hyatt’s pattern of rewriting or shifting claims midway 

through prosecution in applications other than the four at 

issue in this case because that claim shifting “long 

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26 HYATT v. HIRSHFELD

postdate[d] the close of prosecution” of the four applications 

at issue here. Id. at 129–30. The court later concluded that

the PTO’s claim shifting evidence failed to meet the PTO’s 

burden because “it is ‘not unusual to see a few claims rewritten’” and because “the PTO accepted the amendments 

and continued examination” of the applications in question. Id. at 137 (citation omitted). 

The court also refused to consider evidence of Hyatt’s 

pattern of prosecution conduct after 2012, when the PTO 

resumed prosecution of Hyatt’s applications. Id. at 132. It 

explained that it “ascribe[d] no weight to the subsequent 

prosecution history of other applications not before the 

Court following the onset of litigation in these matters.” Id.

The district court likewise reasoned, “That the PTO finally, 

in 2015, got fed-up enough with the difficulties of examining Mr. Hyatt’s claims that it began issuing prosecution 

laches rejections, does not itself have any relevance to this 

Court’s treatment of the applications’ respective prosecution histories through 2002.” Id. at 136–37. 

The district court also discounted evidence of Hyatt’s 

October 1995 agreement with Director Godici because the 

parties “did not reach any agreement that the Court can 

now enforce.” Id. at 135. The district court further gave 

“little weight” to the fact that, in recent years, the PTO has 

spent more than $10 million administering Hyatt’s applications whereas Hyatt has spent approximately $7 million 

in fees. Id. at 137. 

In addition, the court discounted evidence that Hyatt 

had filed four claims that he had already lost in interference proceedings. The court explained that this “unreasonable conduct as to four allegedly illustrative claims does 

very little to move the ball in consideration of the totality 

of Mr. Hyatt’s conduct across approximately 115,000 

claims.” Id. at 138. 

These examples of discounting or ignoring evidence—

indeed swaths of evidence in certain situations—regarding

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HYATT v. HIRSHFELD 27

Hyatt’s prosecution conduct as a cause for delay illustrate 

that the district court failed to follow this court’s guidance 

on considering the totality of the circumstances. We have 

explained that “an examination of the totality of the circumstances, including the prosecution history of all of a series of related patents and overall delay in issuing claims, 

may trigger laches.” Symbol Technologies II, 422 F.3d at

1386. Rather than consider the relevant evidence of conduct causing delay across Hyatt’s GATT Bubble applications—which overlapped, for example, in subject matter, 

claim scope, and priority disclosures, and were filed together as photocopies of a small group of applications—the 

district court erred in considering only the period up to 

2002 and erred insofar as it focused its analysis on the four 

specific applications at issue in this case to the exclusion of 

Hyatt’s other GATT Bubble applications. The district court 

did not appreciate the PTO’s evidence as that of a consistent pattern of conduct across an enormous body of similar applications. The district court’s review of the evidence

did not, therefore, encompass the totality of the circumstances. 

Undue Emphasis on the PTO’s Conduct

The district court further applied an incorrect legal 

standard in a way that affected its entire decision: Rather 

than analyze the evidence to determine whether Hyatt’s 

conduct warrants a finding of prosecution laches, the court

repeatedly placed blame on the PTO for the slowness with 

which Hyatt’s applications were prosecuted. 

We have explained that “a delay by the PTO cannot excuse the appellant’s own delay.” Bogese, 303 F.3d at 1369. 

Although the district court gave lip service to this principle, 

it effectively used the “totality of the circumstances” standard as a vehicle for blaming the PTO for the prosecution

delays. See, e.g., Iancu, 332 F. Supp. 3d at 122 (stating that 

“under the totality of circumstances test[, the] PTO’s actions and omissions can likewise be considered in 

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28 HYATT v. HIRSHFELD

determining the reasonableness of any delay actually attributable to the applicant”); see also id. at 132 (stating that 

the totality of circumstances includes “the greater context 

of his interactions with PTO, and the agency’s actions or 

failures to act, of which the near-decade of suspended examination is but one example”). Notably, the district court 

cited no legal authority supporting its emphasis on the 

PTO’s actions and inactions. 

Specifically, the district court faulted the PTO for using 

its normal procedures when examining Hyatt’s applications. Id. at 132–33. The court reasoned that the atypical 

nature of Hyatt’s GATT Bubble applications “required [the 

PTO] to employ and embrace atypical procedures for addressing the challenge before them.” Id. at 133. There is 

no legal requirement, the court explained, for the PTO to 

be “wedded” to its policy of using compact prosecution. Id. 

The court placed responsibility squarely on the PTO for the 

fact that processing Hyatt’s applications was like trying to 

fit a “large proverbial square peg” into “the rounded-out 

and well-trodden hole of its 3,000 page practice manual.” 

Id. at 134. 

The district court also erroneously found that the PTO 

is solely responsible for the suspension of prosecution from 

2003 to 2012—which the PTO did not rely on to prove delay. See id. at 131. It reasoned that the PTO’s stipulation 

on that score “functions as an admission that the PTO 

shoulders responsibility for the delay during that period.” 

Id. But the PTO’s stipulation, which was offered by the 

PTO but not ultimately agreed upon by the PTO and Hyatt, 

was an attempt by the PTO to streamline the trial. Appellant’s Br. 17 n.4. The PTO argues, persuasively, that the 

“period was directly attributable to Mr. Hyatt’s numerous 

challenges to USPTO procedures because, depending on 

the outcome of those cases, time the USPTO spent examining roughly 400 pending applications could have been rendered meaningless.” Id. 

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HYATT v. HIRSHFELD 29

The court also faulted the PTO for not taking actions 

that it could have taken during the restricted period the 

court considered, i.e., up to 2002. It pointed out that the 

“PTO had ample opportunity over many years to act to resolve its difficulties through formal means” instead of 

“await Mr. Hyatt’s help, which, it appears obvious, was not 

forthcoming.” Iancu, 332 F. Supp. 3d at 134. Because it 

did not use more “formal means,” the district court explained, the PTO failed to give Hyatt adequate notice and 

opportunity to cure “the allegedly offensive conduct.” Id.

The district court also relied on the fact that the PTO did 

not “take action to enforce compliance with the informal 

agreements it now argues it had with Mr. Hyatt.” Id. at 

135. Summing up, the court stated that “the PTO itself did 

nothing to police the conduct they now complain of for the 

better part of two decades.” Id. at 137. 

While faulting the PTO in the ways described above, 

the district court repeatedly emphasized the broad latitude 

and discretion that applicants including Mr. Hyatt have in 

prosecuting their applications as they choose within the 

law and PTO regulations. See, e.g., id. at 134 (stating that 

Hyatt had “discretion as to how to prosecution [his] 

claims”). According to the court, Hyatt would have assisted 

the PTO if it were “in Mr. Hyatt’s interest to” do so, and 

Hyatt should not be penalized for choosing “instead to pursue his own private enterprise while the bureaucracy fulfills its duties to the applicant and to the public.” Id. 

Similarly, the court explained that, although Hyatt “‘could 

have’ been more helpful during the examination process,” 

“there is no abstract requirement for a citizen to tailor his 

conduct in pursuit of his constitutional right to a patent, to 

conform to what is ‘feasible’ for the agency.” Id. at 135. 

However, the doctrine of prosecution laches itself—the subject of the district court’s analysis—is one example of an 

obligation to tailor prosecution conduct in pursuit of patent 

rights. 

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30 HYATT v. HIRSHFELD

In the above ways, the district court erred by improperly focusing the analysis on the PTO’s conduct rather than 

Hyatt’s conduct. It is not the case that an applicant may 

prosecute his patents however he or she wishes within the 

statute and PTO regulation, because the doctrine of prosecution laches places an additional, equitable restriction on 

patent prosecution conduct beyond those imposed by statute or PTO regulation. An applicant must therefore not 

only comply with the statutory requirements and PTO regulations but must also prosecute its applications in an equitable way that avoids unreasonable, unexplained delay 

that prejudices others. See Cancer Research, 625 F.3d at 

729. 

Further, the PTO’s conduct may be considered in the 

totality of circumstances, but its delay “cannot excuse the 

[applicant’s] own delay” in prosecution. Bogese, 303 F.3d 

at 1362. Indeed, the patent statute already deals with delay by the PTO when it provides for patent term adjustment to account for that delay. See 35 U.S.C. § 154(b); 

Supernus, 913 F.3d at 1353. The PTO’s delay therefore 

provides a weak reason to negate prosecution laches, which 

asks a separate question of whether the patent should issue, or if issued is enforceable, in light of the applicant’s 

prosecution conduct. 

Nor does the PTO’s failure to adopt special procedures 

to accommodate extreme prosecution conduct negate prosecution laches. The PTO is entitled to adopt rules and practices to efficiently administer the patent examination 

system set up by the patent statute. Requiring the PTO to 

adopt tailored approaches to make sure that each applicant 

that delays, is unresponsive, or is otherwise outside normal 

prosecution conduct successfully progresses through prosecution would impose obligations on the PTO not contemplated by the statute. The applicant is in the driver’s seat 

and must take care to avail itself of the PTO’s beneficial 

patent examination process as it stands and in a way that 

avoids undue delay leading to prejudice imposed on others. 

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HYATT v. HIRSHFELD 31

Here, the PTO’s instructions to, for example, provide written description support and priority date support, its instructions to demarcate the applications, its creation of a 

new art unit, and its issuance of atypical Requirements 

demonstrate that the PTO did not stand back and do nothing, but rather it notified Hyatt of its own obligations and 

requirements and thereby gave him the opportunity to 

avoid prosecution laches. Prosecution laches does not 

strictly require formalized notice, warnings, or office actions, although those may well lend support to a prosecution laches finding. 

In sum, the district court’s restricted view of the record, 

as well as its overemphasis on the PTO’s actions and inactions and its repeated excuse of Hyatt’s prosecution conduct, amounted to a misapplication of the legal standard 

governing prosecution laches. We clarify, consistent with 

the above discussion and our past precedent, that prosecution laches considers the totality of circumstances, Symbol 

Technologies II, 422 F.3d at 1386, and that the PTO’s delay 

does not excuse an applicant’s delay, Bogese, 303 F.3d at 

1369. 

D

We turn to the question of whether the PTO’s prosecution laches evidence and arguments presented at trial are

enough to shift the burden to Hyatt. We hold that they are. 

Unreasonable and Unexplained Delay

Whether an applicant’s delay is unreasonable depends 

on the specific circumstances. A.C. Aukerman Co. v. R.L. 

Chaides Const. Co., 960 F.2d 1020, 1032 (Fed. Cir. 1992), 

overruled on other grounds by SCA Hygiene Prods. Aktiebolag v. First Quality Baby Prods., LLC, 137 S. Ct. 954 

(2017); see also Advanced Cardiovascular Sys., Inc. v. 

Scimed Life Sys., Inc., 988 F.2d 1157, 1162 (Fed. Cir. 1993)

(“The reasonableness of the behavior of the person against 

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32 HYATT v. HIRSHFELD

whom laches is asserted depends on the facts of the particular case.”). 

As described above, the trial record shows that Hyatt 

filed 381 applications during the GATT Bubble—the most 

of any filer. Each application was a photocopy of one of 11 

earlier parent applications, and each had a small set of 

claims, many of which were identical to each other. Simply 

put, Hyatt’s applications were placeholders. Director Godici then met with Hyatt instructing Hyatt to focus each application on a separate invention, and Hyatt agreed. Since 

then, Hyatt has expanded his claim count to at least 

115,000, an average of about 300 per application. 

The magnitude of Hyatt’s delay in presenting his 

claims for prosecution suffices to invoke prosecution laches. 

On multiple occasions, the Supreme Court has found patents unenforceable based on eight- and nine-year prosecution delays. See, e.g., Woodbridge, 263 U.S. at 53, 56 (nineand-a-half-year delay); Webster Electric, 264 U.S. at 465 

(eight-year delay); see also Bogese, 303 F.3d at 1369 (eightyear delay). The PTO presented evidence establishing that 

Hyatt’s four applications at issue claimed priority to applications filed in the early 1970s and 1980s, meaning that 

Hyatt delayed between 12 to 28 years to present his claims 

for prosecution. In fact, the PTO presented additional evidence that Hyatt had delayed similar amounts across all 

his GATT Bubble applications. The following table presented at trial, for example, demonstrates Hyatt’s delay 

across all pertinent applications:

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HYATT v. HIRSHFELD 33

J.A. 30211.9 

Hyatt disputes that the claims at issue were delayed 

12 to 28 years. Relying on the latest possible priority dates, 

Hyatt argues that he delayed only seven to 11 years to file 

the four applications at issue and between 10 and 19 years 

before presenting the claims now in dispute. See Appellee’s 

Br. 27; Appellant’s Response and Reply Br. 7. Even accepting Hyatt’s arguments on this score, these quantities of 

time are enough to trigger prosecution laches. See, e.g., 

Woodbridge, 263 U.S. at 53, 56; Webster Electric, 264 U.S. 

at 465; Bogese, 303 F.3d at 1369. 

Beyond merely the magnitude of Hyatt’s delay in filing 

his claims, Hyatt adopted an approach to prosecution that 

all but guaranteed indefinite prosecution delay. The PTO 

9 This table includes the four Hyatt applications at 

issue in this case: the ’639 application is in family 8; the 

’211 and ’398 applications are in family 10; and the ’062 

application is in family 12. 

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34 HYATT v. HIRSHFELD

presented evidence at trial demonstrating that multiple

characteristics of Hyatt’s application and claim web, when 

combined, made it effectively impossible for the PTO to process them. 

For one, the applications claim priority to a large number of earlier applications, creating a large number of possible priority dates. This reality frustrated the examiners’ 

ability to take the preliminary step of identifying the relevant body of prior art for purposes of examining the claims. 

E.g., J.A. 29425–26.

Exacerbating this problem was the length and complexity of both the specifications themselves and those of 

the priority applications. As Mr. Morse testified, it was not 

enough for an examiner to merely find a claim element or 

group of claim elements in a claimed priority reference; instead, the examiner had to identify the particular interconnection of elements claimed, which was extraordinarily 

difficult and time consuming. J.A. 29435–36, 29544, 

29570–71. Notably, the PTO did not digitize its files until 

2003, so before that point examiners needed to wade 

through large stacks of paper to determine, for example, 

written description or the priority date. J.A. 29419–20 

(“You would have 30-foot high stacks you would be comparing against each other looking for double patenting.”). 

Even in determining written description long after the documents became digitized, the district court noted that it 

took “many weeks of trial,” relying “heavily upon the new 

evidence presented at trial, in the form of expert testimony,” to make the written description findings. J.A. 87 

n.22. Despite these challenges’ obvious effect of delaying 

prosecution, Hyatt went many years failing to identify

written description support for his claims. See, e.g., 

J.A. 36700–01. 

Hyatt also engaged in a pattern of filing amendments 

adding hundreds of claims to each application, effectively 

starting examination from the beginning. See, e.g., 

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HYATT v. HIRSHFELD 35

J.A. 31869–72. Many of these claims were not unique; instead Hyatt repeatedly filed identical or patentably indistinct claims across different applications. See, e.g.,

J.A. 31874–84. Hyatt further frustrated examiners by engaging in a pattern of rewriting claims entirely or in significant part midway through prosecution, thereby, again, 

restarting examination. E.g., J.A. 29550–51.

All of the above patterns of prosecution conduct created 

a perfect storm that overwhelmed the PTO. See, e.g., 

J.A. 29981–83. It was virtually impossible for examiners 

to perform a double patenting analysis. See, e.g.,

J.A. 29912. The same was true, as already mentioned, 

with respect to determining priority dates and identifying 

written description support. The PTO’s witnesses testified 

that Hyatt’s approach to prosecution was unique and created an “extreme situation” at the PTO. E.g., J.A. 29417–

21, 29467–68, 29471–73, 29893, 29980–81. 

The PTO also showed that Hyatt had engaged in specific, exemplary acts during prosecution that were patently 

unreasonable. For example, Hyatt filed claims that he had 

previously lost in interference proceedings. Iancu, 

332 F. Supp. 3d at 138. Whether Hyatt did so purposely is 

not material because these actions suggest, at a minimum, 

that his prosecution approach had overwhelmed even his 

own ability to manage his applications and claims. 

We also conclude that no reasonable explanation has 

been shown to justify Hyatt’s prosecution approach. As the 

record shows, Hyatt agreed with Director Godici in October

1995 to demarcate his applications, but he then did precisely the opposite to an extreme degree. Twenty years 

later, Hyatt acknowledged he lacked a “master plan” for 

demarcating his applications. Iancu, 332 F. Supp. 3d at 

132 n.12; J.A. 204921. Any goal Hyatt may have had of, for 

example, correctly capturing his inventions or steering 

clear of prior art, as Hyatt argued at the dismissal stage, 

could not come close to justifying the particular, multiCase: 18-2390 Document: 89 Page: 35 Filed: 06/01/2021
36 HYATT v. HIRSHFELD

faceted approach he took to prosecution when viewed in its 

entirety. See, e.g., Pl.’s Opp. to Def.’s Mot. to Dismiss for 

Prosecution Laches at 12, Hyatt v. Matal, No. 1:05-cv02310-RCL (D.D.C. Jan. 9, 2017), ECF No. 101. Nor can

the contention that some or all of Hyatt’s conduct was not 

literally violative of law or PTO regulation provide an adequate explanation under these circumstances. See id. Hyatt’s conduct—including his delay in presenting claims, his 

creation of an overwhelming, duplicative web of applications and claims, and his failure to cooperate with the 

PTO—was a clear abuse of the patent system, even if it did 

not literally violate regulations or statutory provisions. 

When the above circumstances are considered in their 

totality, we believe the conclusion is inescapable that the 

PTO satisfied its burden of proving that Hyatt engaged in 

unreasonable and unexplainable delay, as prosecution 

laches requires. Hyatt’s pattern of conduct resembles, but 

goes well beyond, Bogese’s consistent pattern of receiving 

a rejection on an application, filing a continuation application without any amendments, and abandoning the original application. Bogese, 303 F.3d at 1364–65. Hyatt’s

time-wasting process obstructed the PTO from examining 

not only Hyatt’s four applications at issue, but nearly all of 

his GATT Bubble applications. 

Prejudice10

This case requires us to address the prejudice requirement of prosecution laches for the first time in a case where 

10 Although the parties briefed the prejudice element 

of prosecution laches during the district court action, the 

district court did not squarely address the issue in its order 

on prosecution laches. See generally Iancu, 332 F. Supp. 3d 

at 113–39; see also Def.’s Mot. to Dismiss for Prosecution 

Laches at 41–43, Hyatt v. Matal, No. 1:05-cv-02310-RCL 

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HYATT v. HIRSHFELD 37

the PTO asserts the defense in a § 145 action. Our precedent to date establishes that, to prove prosecution laches 

in the context of an infringement action, an accused infringer must prove prejudice attributable to the patentee’s 

delay. Cancer Research, 625 F.3d at 729. Proving prejudice in that context requires proving intervening rights, 

i.e., “that either the accused infringer or others invested in, 

worked on, or used the claimed technology during the period of delay.” Id. 

In the context of laches, we have held that a delay of 

more than six years raises a “presumption that it is unreasonable, inexcusable, and prejudicial.” Wanlass v. Gen. 

Elec. Co., 148 F.3d 1334, 1337 (Fed. Cir. 1998). That presumption shifts the burden to the patentee to prove that 

“either the patentee’s delay was reasonable or excusable 

under the circumstances or the defendant suffered neither 

economic nor evidentiary prejudice.” Id. Presumptions of 

fact such as this “have been created to assist in certain circumstances where direct proof of a matter is for one reason 

or another rendered difficult.” Panduit Corp. v. All States 

Plastic Mfg. Co., 744 F.2d 1564, 1581 (Fed. Cir. 1984), overruled on other grounds by Richardson-Merrell, Inc. v. 

Koller, 472 U.S. 424 (1985). Presumptions “arise out of considerations of fairness, public policy, and probability, and 

are useful devices for allocating the burden of production 

of evidence between the parties.” Id. 

Hyatt argues that the district court’s decision should 

be affirmed because the PTO did not adequately prove intervening rights. Appellee’s Br. 56. The PTO responds 

that the intervening rights requirement does not apply to 

the PTO in the context of a § 145 action to obtain a patent. 

Appellant’s Response and Reply Br. 36–37. Consistent 

(D.D.C. Nov. 22, 2016), ECF No. 91; Pl.’s Opp. to Def.’s Mot.

to Dismiss for Prosecution Laches at 27–29, Hyatt v. Matal, 

No. 1:05-cv-02310-RCL (D.D.C. Jan. 9, 2017), ECF No. 101.

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38 HYATT v. HIRSHFELD

with both Cancer Research and Wanlass, we now hold that, 

in the context of a § 145 action, the PTO must generally 

prove intervening rights to establish prejudice, but an unreasonable and unexplained prosecution delay of six years 

or more raises a presumption of prejudice, including intervening rights. Applying these principles, we conclude that 

the PTO’s demonstration of an unreasonable and unexplained delay by Hyatt, which exceeds six years by any 

measure, shifts the burden to Hyatt to prove lack of prejudice. 

We further hold that, where a patent applicant has 

committed a clear abuse of the PTO’s patent examination

system, the applicant’s abuse and its effects meet the prejudice requirement of prosecution laches. A clear abuse of 

the patent system occurs when, for example, the applicant’s conduct unduly increases the administrative burden 

on the PTO and thereby effectively taxes everyone using

the system. Such abuse also demonstrates a dangerous 

likelihood that the applicant is harming the public’s interests more broadly, diminishing the patent system’s benevolent nature, and stifling innovation and creativity in the 

useful arts. In rare circumstances like these, an applicant’s conduct and its effects on the PTO can alone suffice

to prove prejudice for purposes of the prosecution laches 

defense in a § 145 action. 

We conclude that the PTO has carried its burden of 

proving that Hyatt engaged—intentionally or not—in a 

clear abuse of the PTO’s patent examination system that 

contributed to delay in the four applications at issue. Barring significant evidence to the contrary from Hyatt, the 

PTO has therefore demonstrated material prejudice. Hyatt’s approach to prosecuting his GATT Bubble applications made it impossible for the PTO to process them using 

its normal compact prosecution procedures. The PTO created an art unit to deal specifically with his applications 

and began using atypical procedures to ascertain the information needed to process the applications. The PTO spent 

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HYATT v. HIRSHFELD 39

approximately $10 million administering Hyatt’s applications over a period of about five years—during which Hyatt 

paid only $7 million in fees. Iancu, 332 F. Supp. 3d at 137. 

The new art unit was capable of examining about 900 typical applications per year but could not come close to that 

number when examining Hyatt’s applications. J.A. 31885. 

According to PTO data, a typical examiner could prepare 

an office action for a typical application in two to three 

days, but each office action for Hyatt’s applications took approximately four months. J.A. 31885–86. The PTO therefore estimated that it would take 532 years of examiner 

time to complete the prosecution of his roughly 400 applications, during which it could complete over 40,000 typical 

applications. J.A. 31886.11 These exemplary figures, combined with the details surrounding Hyatt’s pattern of prosecution conduct, show that the PTO has carried its burden 

of proving that Hyatt’s prosecution of his applications 

clearly abused the PTO’s patent examination system and 

that that clear abuse contributed to the delay that occurred 

with respect to the four applications at issue. Under our 

holdings above, this abuse may establish prejudice for prosecution laches purposes. 

DISPOSITION

In certain circumstances this court and our sister circuits have retained jurisdiction over appeals and held them 

in abeyance pending resolution of a limited issue. See, e.g., 

11 The PTO’s expert additionally opined, based on 

PTO data, that the average GATT Bubble application undergoes three office actions, while Hyatt’s have undergone 

on average 15.7 office actions. J.A. 39279. He also opined 

that comparing each of Hyatt’s 115,000 pending claims to 

each other to determine double patenting would require 6.6 

billion comparisons, and that, assuming one minute per 

comparison, that analysis would take over 12,000 years. 

J.A. 39280. 

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40 HYATT v. HIRSHFELD

Tempur-Pedic Mgmt., Inc. v. FKA Distrib. Co., 481 F. 

App’x 615 (Fed. Cir. 2012); Endo Pharms. Inc. v. Teva 

Pharms. USA, Inc., 729 F. App’x 936, 938 (Fed. Cir. 2018); 

Patel v. Haro, 443 F. App’x 17, 18 (5th Cir. 2011) (“We retain jurisdiction over the appeal except for the purposes of 

the limited remand.”); Sickle v. Torres Advanced Enter. 

Sols., LLC, 653 F. App’x 763, 764 (D.C. Cir. 2016) (“[T]his 

case will be held in abeyance pending resolution of the limited jurisdictional question on remand.”); United States v. 

Hinojosa-Bencomo, 7 F.3d 1045 (10th Cir. 1993) (“We retain jurisdiction over the balance of this case and hold in

abeyance our judgment pending resolution of United States 

v. Nichols.”); Hayden v. Pataki, 449 F.3d 305, 371 (2d Cir. 

2006); Carnegie Mellon Univ. v. Schwartz, 105 F.3d 863, 

867 (3d Cir. 1997). Consistent with this precedent, and 

given the potential for the prosecution laches issue to resolve the entire case at hand, we retain jurisdiction over 

the appeal with respect to the anticipation and written description issues, and we remand to the district court for the 

limited purpose of affording Hyatt the opportunity to present evidence on the issue of prosecution laches, consistent 

with the standards set forth in this opinion. See Int’l Union, United Auto., Aerospace & Agric. Implement Workers 

of Am., UAW v. Mack Trucks, Inc., 917 F.2d 107, 110–11

(3d Cir. 1990) (“[A] defendant moving for a directed verdict 

retains the right to present evidence against the plaintiff's 

case whether its motion is denied at the trial or appellate 

level.”). 

On remand, the district court should bear several 

points in mind. First, regarding the unreasonable and unexplained delay requirement of prosecution laches, the record shows that Hyatt has already proffered a number of 

reasons for his delay, including that he timely completed 

examination four applications at issue; that his conduct 

during prosecution of his other GATT Bubble applications 

is irrelevant to the prosecution laches analysis; that he 

filed his GATT Bubble applications to cover a number of 

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HYATT v. HIRSHFELD 41

inventions he believed he had made; and Hyatt met statutory requirements and followed the PTO’s rules in prosecuting his applications. We conclude that, under the 

circumstances of this case, these reasons without more are 

insufficient as a matter of law to negate that Hyatt’s delay 

was unreasonable and unexplained. To carry his burden, 

Hyatt must show by preponderance of evidence that Hyatt 

had a legitimate, affirmative reason for his delay. Such a 

reason must operate to excuse Hyatt from responsibility for 

the sizable undue administrative burden that his applications have placed on the PTO in its efforts to process Hyatt’s applications, which the record before us demonstrates 

to be extreme. More specifically, any satisfactory reason 

must, at a minimum, justify Hyatt’s decision to ignore Director Godici’s instruction to demarcate his applications in 

1995; justify his decision to adopt the specific prosecution 

approach that he did—unique in its scope and nature—as 

detailed in the PTO’s Requirements; and justify his failure 

to develop a plan for demarcating his applications over at 

least the 20 year period from 1995 to 2015, see, e.g., 

J.A. 204921. Any reasons that fall short of justifying those 

decisions or omissions fail to negate that his delay has been 

unreasonable and unexplained. We can divine no reason 

in the record currently before the court that would suffice, 

but Hyatt is entitled as a matter of fairness to present evidence and be heard on this issue. 

In determining whether Hyatt’s delay has caused prejudice, the district court should bear in mind that, as we 

explain above, Hyatt’s delay of more than six years, by any 

measure, shifts the burden to Hyatt to prove that Hyatt’s 

delay has not caused the PTO or any third party material 

prejudice. The district court should also bear in mind our 

conclusion above that the PTO has carried its burden of 

proving that Hyatt’s prosecution conduct amounted to a 

clear abuse of the PTO’s patent examination system, which 

may alone suffice to satisfy the prejudice requirement of 

prosecution laches. The record before us shows, for 

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42 HYATT v. HIRSHFELD

example, that the PTO has created a distinct art unit for 

Hyatt’s applications; that the PTO has recently spent millions more dollars processing Hyatt’s applications than Hyatt has paid in fees; that examiners have spent inordinate 

amounts of time preparing office actions; and that the PTO 

has resorted to special, customized procedures involving its 

Requirements to process Hyatt’s applications. We again 

cannot guess what might negate this evidence of prejudice. 

But be that as it may, we recognize that Hyatt is entitled 

to present evidence that his delay did not cause prejudice. 

CONCLUSION

The PTO carried its burden of proving prosecution 

laches, and the district court erred in granting Hyatt’s Rule 

52(c) motion for judgment on partial findings. We vacate 

the district court’s grant of the motion, and we remand for 

the district court to conduct further proceedings, as 

promptly as possible consistent with principles of fairness, 

affording Hyatt the opportunity to present evidence on 

prosecution laches. We hold in abeyance this appeal with 

respect to the issues of anticipation and written description 

pending the district court’s remand decision on prosecution 

laches. We have considered the parties’ remaining arguments and do not find them persuasive or do not reach 

them. For the above reasons, we vacate-in-part and remand for further proceedings consistent with this opinion. 

VACATED-IN-PART AND REMANDED

COSTS

No costs. 

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