United States Court of Appeals 

for the Federal Circuit ______________________ 

HOLOGIC, INC., CYTYC SURGICAL PRODUCTS, 

LLC,

Plaintiffs-Appellants

v.

MINERVA SURGICAL, INC.,

Defendant-Cross-Appellant

______________________ 

2019-2054, 2019-2081

______________________ 

Appeals from the United States District Court for the 

District of Delaware in No. 1:15-cv-01031-JFB-SRF, Senior 

Judge Joseph F. Bataillon.

______________________ 

Decided: August 11, 2022

______________________ 

MATTHEW WOLF, Arnold & Porter Kaye Scholer LLP, 

Washington, DC, argued for plaintiffs-appellants. Also 

represented by MARC A. COHN, JENNIFER SKLENAR. 

 ROBERT N. HOCHMAN, Sidley Austin LLP, Chicago, IL, 

argued for defendant-cross-appellant. Also represented by 

CAROLINE A. WONG; JILLIAN STONECIPHER, Washington, 

DC; VERA ELSON, Wilson Sonsini Goodrich & Rosati, PC, 

Palo Alto, CA; OLIVIA M. KIM, EDWARD POPLAWSKI, Los Angeles, CA. 

 ______________________ 

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2 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

Before STOLL, CLEVENGER, and WALLACH, Circuit Judges.

STOLL, Circuit Judge. 

This case comes to us on remand from the Supreme 

Court. The Court vacated our judgment affirming the district court’s summary judgment of no invalidity for claim 1 

of U.S. Patent No. 9,095,348 in favor of Hologic, Inc. and 

Cytyc Surgical Products, LLC (collectively, “Hologic”)

based on the doctrine of assignor estoppel. The Supreme 

Court held that assignor estoppel remains a valid doctrine, 

but that it comes with limits. The Court remanded for us 

to consider whether assignor estoppel, as limited, precludes Minerva Surgical, Inc. from challenging the validity 

of claim 1. Specifically, we must determine whether 

claim 1 is “materially broader” than the claims assigned to 

Hologic such that assignor estoppel should not apply. 

For the reasons below, we hold that claim 1 is not “materially broader” than the claims assigned to Hologic. Accordingly, Minerva is estopped from challenging the 

validity of claim 1 of the ’348 patent. We therefore affirm 

the district court’s summary judgment that claim 1 is not 

invalid. We also reinstate our earlier judgment in all other 

respects. 

BACKGROUND

I 

The facts igniting the parties’ dispute go back nearly 

thirty years. In 1993, Csaba Truckai (one of the named 

inventors of the ’348 patent) co-founded a company called 

NovaCept, Inc. Mr. Truckai and his team at NovaCept invented the NovaSure system, an endometrial ablation device used to treat abnormal uterine bleeding (menorrhagia) 

by destroying targeted cells in the lining of the uterus. 

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A 

On June 23, 1998, Mr. Truckai filed U.S. Patent Application No. 09/103,072, titled “A Moisture Transport System for Contact Electrocoagulation,” which included 31 

claims of varying breadth. Of particular relevance here, 

some claims recited a “fluid permeable elastic member” to 

pass moisture away from the tissue, while one claim—

claim 31—did not. Compare J.A. 40357 (claim 1) and

J.A. 40359–60 (claim 16), with J.A. 40362 (claim 31).

Mr. Truckai assigned his interest in the ’072 application to NovaCept in August 1998. While the ’072 application was pending at the U.S. Patent and Trademark Office, 

Cytyc Corporation acquired NovaCept for $325 million in 

March 2004. As part of this acquisition, NovaCept assigned its intellectual property rights to Cytyc, including 

rights to its patents and any continuation, continuation-inpart, or divisional patent applications (which included the 

’072 application). In the agreement, NovaCept warranted 

the validity and enforceability of the intellectual property

rights it assigned. Relevant here, NovaCept warranted 

that it had “no present knowledge from which it could reasonably conclude” that the assigned intellectual property 

rights were invalid or unenforceable. J.A. 36367 ¶ 3.9(e). 

The ’072 application issued as U.S. Patent No. 6,813,520 in 

November 2004. 

Mr. Truckai eventually left NovaCept and, in 2008, 

founded Minerva, serving as its President, Chief Executive 

Officer, and a member of its Board of Directors. 

Mr. Truckai and others at Minerva developed the Endometrial Ablation System (EAS), which received FDA approval 

in 2015. Minerva began commercial distribution of the 

EAS in August 2015.

B 

Hologic acquired Cytyc in 2007 and is the current assignee of the’348 patent at issue in this litigation. The 

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4 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

’348 patent issued in 2015 and claims priority to the 

’072 application through a series of continuation and divisional applications. 

The ’348 patent written description states that the inventors developed an ablation device that eliminates the 

problem of “steam and liquid buildup at the ablation site,” 

which occurred with prior art ablation devices. ’348 patent 

col. 2 ll. 25–30. According to the written description, moisture buildup in prior art devices “create[d] a path of conductivity through which current traveling through the 

electrodes” flowed, “prevent[ing] the current from traveling 

into the tissue to be ablated.” Id. at col. 2 ll. 9–12. As the 

written description explains, the current then heated the 

water drawn from the tissue, “turn[ing] the ablation process into a passive heating method in which the heated liquid around the electrodes cause[d] thermal ablation to 

continue well beyond the desired ablation depths.” Id.

at col. 2 ll. 15–18. To overcome this moisture problem, the 

written description explains that the claimed devices can 

be constructed so “moisture generated during dehydration 

is actively or passively drawn . . . away from the tissue.” 

Id. at col. 2 ll. 40–45. 

An exemplary ablation device comprises three major 

components: (1) an applicator head, (2) a main body, and 

(3) a handle. Id. at col. 4 ll. 55–58. The applicator head 

“includes an electrode carrying means” with “an array of 

electrodes” on the surface of the electrode carrying means. 

Id. at col. 4 ll. 58–61. The written description explains that 

the electrode carrying means “is preferably a sack formed 

of a material which is non-conductive” and “permeable to 

moisture and/or . . . has a tendency to absorb moisture.” Id.

at col. 5 ll. 52–57. Enclosed within the electrode array is a 

deflecting mechanism and its deployment structure. Id.

at col. 13 ll. 8–12. According to the written description, the 

deflecting mechanism is “used to expand and tension the 

[electrode] array for positioning into contact with the tissue,” id. at col. 12 ll. 5–8, “form[ing] the [electrode] array 

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into the substantially triangular shape” that “is particularly adaptable to most uterine shapes,” id. at col. 14 

ll. 21–24.

Claim 1 is the only asserted claim of the ’348 patent. 

Because claim 1’s relevance relates to whether it is materially broader than claim 31 of the ’072 application, we reproduce claim 1 and claim 31 side-by-side in our analysis 

of that question below. See infra p. 14.

II

In November 2015, Hologic sued Minerva in the 

U.S. District Court for the District of Delaware, alleging 

that Minerva’s EAS and the use thereof infringed certain 

claims of the ’348 patent. Minerva, in response, asserted 

various invalidity defenses, including lack of enablement 

and written description. Hologic moved for summary judgment, arguing that the doctrine of assignor estoppel bars 

Minerva from challenging the validity of the ’348 patent 

claims in district court. The district court agreed, entering

summary judgment of no invalidity in Hologic’s favor. See

Hologic, Inc. v. Minerva Surgical, Inc., 325 F. Supp. 3d 

507, 523–25 (D. Del. 2018) (Hologic I). It also granted summary judgment of infringement of claim 1 of the ’348 patent. See id. at 529–32. 

After a jury trial on the issues of willful infringement, 

damages, and certain state-law counterclaims, both parties 

appealed, raising numerous issues in this court. In its 

cross-appeal, Minerva challenged (among other things) the 

district court’s determination that assignor estoppel precluded Minerva from challenging the validity of claim 1 of 

the ’348 patent. It also challenged the district court’s claim 

constructions of two terms in claim 1—“applicator head” 

and “indicator mechanism”—relevant to infringement. We 

concluded that the district court did not abuse its discretion 

in applying the doctrine of assignor estoppel and accordingly affirmed its summary judgment of no invalidity. Hologic, Inc. v. Minerva Surgical, Inc., 957 F.3d 1256, 

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6 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

1267–69 (Fed. Cir. 2020) (Hologic II). We also adopted the 

district court’s constructions of the terms that Minerva 

challenged, thus affirming the district court’s summary 

judgment of infringement. See id. at 1269–70.

Minerva petitioned the Supreme Court for a writ of certiorari, arguing that the doctrine of assignor estoppel “finds 

no support in the statute, [the Supreme] Court’s decisions, 

or the policies the Patent Act serves.” Pet. for Writ of Cert.

at 14, Minerva Surgical, Inc. v. Hologic, Inc., 141 S. Ct. 

2298 (2021) (No. 20-440). To Minerva, its case provided “a 

uniquely valuable opportunity” for the Court to consider 

“not only whether to abandon the doctrine entirely, but also 

whether to retain the doctrine with clearly defined, narrow 

limits.” Id. at 28–29. 

The Supreme Court granted certiorari and declined Minerva’s request to “discard this century-old form of estoppel,” but in doing so clarified that assignor estoppel “comes 

with limits.” Minerva Surgical, Inc. v. Hologic, Inc., 

141 S. Ct. 2298, 2302, 2309 (2021) (Hologic III). It explained that the doctrine “reaches only so far as the equitable principle long understood to lie at its core.” Id.

at 2302. The Court thus held that assignor estoppel “applies only when an inventor says one thing (explicitly or 

implicitly) in assigning a patent and the opposite in litigating against the patent’s owner.” Id. at 2304. Put another 

way, the Court explained that “there is no ground for applying assignor estoppel” “when the assignor has made neither explicit nor implicit representations in conflict with an 

invalidity defense.” Id. at 2310.

The Supreme Court then considered Minerva’s contention that “estoppel should not apply because it was challenging a claim that was materially broader than the ones 

[Mr.] Truckai had assigned,” id. at 2310, a contention that 

our precedent had deemed irrelevant, Hologic II, 957 F.3d 

at 1268. The Court disagreed with our conclusion, explaining that Minerva’s contention was important to whether 

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HOLOGIC, INC. v. MINERVA SURGICAL, INC. 7

estoppel should apply: “If Hologic’s new claim is materially 

broader than the ones [Mr.] Truckai assigned, then 

[Mr.] Truckai could not have warranted its validity in making the assignment. And without such a prior inconsistent 

representation, there is no basis for estoppel.” Hologic III, 

141 S. Ct. at 2311. The Court thus vacated our judgment 

and remanded for us to address “whether Hologic’s new 

claim is materially broader than the ones [Mr.] Truckai assigned.” Id. 

We therefore reconsider whether the district court 

abused its discretion in determining that assignor estoppel 

barred Minerva’s invalidity defenses in light of the Supreme Court’s guidance. 

DISCUSSION 

The dispute on remand focuses on whether claim 1 of 

the ’348 patent is materially broader than claim 31 of the 

’072 application, a claim that was canceled two years before NovaCept assigned its intellectual property rights to 

Cytyc (Hologic’s predecessor). 

Minerva argues that every claim pending at the time of 

the 2004 assignment “included an express limitation that 

the applicator head be moisture permeable.” Cross-Appellant’s Suppl. Br. 4. Minerva concedes that claim 31 did not 

have such a limitation but asserts that claim 31 was canceled in 2002, well before the 2004 assignment, and therefore it was not assigned. Minerva thus argues that Hologic 

cannot assert that Mr. Truckai1 represented claim 31 was 

valid at the time of the 2004 assignment. Minerva further 

argues that even if Hologic can properly rely on claim 31, 

that claim did not cover a device with a moisture-impermeable applicator head because it did not use the term “applicator head.” And it argues that the written description 

1 We use “NovaCept” and “Mr. Truckai” interchangeably when referencing the 2004 assignment. 

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8 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

makes clear that the term “electrode array,” as used in 

claim 31, requires a moisture-permeable electrode array. 

Thus, per Minerva, claim 1 of the ’348 patent—which covers both moisture-permeable and moisture-impermeable 

devices—is materially broader than claim 31, which is limited to moisture-permeable devices. 

Hologic, for its part, responds first that Mr. Truckai 

warranted claim 31’s validity at the time of the assignment. Hologic acknowledges that claim 31 was canceled 

prior to the 2004 assignment. It argues, however, that the 

context in which this cancelation arose matters: the cancelation was “without prejudice” complying with a restriction requirement entered by the Examiner. According 

to Hologic, under standard patent prosecution practice, the 

expectation is that a patent practitioner could have re-introduced the canceled claim in a continuation or divisional 

application. And further, Hologic notes the Examiner allowed claim 31 on the merits prior to cancelation. Continuing, Hologic argues that claim 1 is not materially broader 

than claim 31 because neither claim has any moisture-permeability limitation.

The questions before us are therefore: (1) whether 

Mr. Truckai warranted claim 31’s validity at the time of assignment, considering the parties’ arguments regarding

the implications of the 2002 cancelation; and (2) whether 

claim 31 is materially broader than claim 1 of the ’348 patent—specifically, whether claim 31 is broad enough to 

cover moisture-impermeable devices, or if instead it is limited to moisture-permeable devices. We address each argument in turn. 

I 

We begin our analysis by considering whether claim 31 

was assigned in the 2004 assignment such that 

Mr. Truckai warranted claim 31’s validity as part of that

assignment. The answer to this question turns on the

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’072 application’s prosecution history and what it tells an 

objective assignee about why claim 31 was canceled. 

As noted above, Mr. Truckai and his co-inventors filed 

the ’072 application on June 23, 1998, with 31 claims. 

J.A. 40293, 40357–62. On June 21, 1999, the Examiner issued an office action rejecting claim 31 as anticipated under 35 U.S.C. § 102. See J.A. 40382–84. Mr. Truckai 

disagreed, arguing in his December 21, 1999 office action 

response that claim 31 was not anticipated by the prior art 

of record. J.A. 40398. Mr. Truckai convinced the Examiner, who allowed claim 31 on October 3, 2000 (while maintaining rejections of other pending claims). J.A. 40416. 

On May 21, 2001, the Examiner issued a restriction requirement for claim 31 under 35 U.S.C. § 121. Section 1212

governs divisional applications and provides that where 

“two or more independent and distinct inventions are 

claimed in one application, the Director may require the 

application to be restricted to one of the inventions.” In the 

restriction requirement, the Examiner explained that certain pending claims (including claim 31) were drawn to an 

apparatus for ablating and that other pending claims were 

drawn to a method of ablating. J.A. 40442–43. That is, the 

Examiner concluded that the apparatus claims (including 

claim 31) were distinct inventions from the method claims. 

The Examiner thus required Mr. Truckai to elect which 

claims he wanted to further prosecute in the ’072 application. See 37 C.F.R. § 1.142(a) (“If two or more independent 

and distinct inventions are claimed in a single application, 

the examiner in an Office action will require the applicant 

2 Congress amended § 121 when it enacted the 

Leahy–Smith America Invents Act (AIA). Pub. L. 

No. 112–29, § 4(a)(2), 125 Stat. 284, 295 (2011). We use the 

version of § 121 that was in effect at the time of the May 21, 

2001 office action. 

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10 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

in the reply to that action to elect an invention to which the 

claims will be restricted . . . .”). 

On June 5, 2001, Mr. Truckai requested that the Examiner withdraw the restriction requirement because the 

Examiner had already allowed claim 31. In the alternative, he elected the method claims for further prosecution 

on the merits. The Examiner maintained the restriction 

requirement and noted Mr. Truckai’s election of the 

method claims for further prosecution. In response, on 

February 28, 2002, Mr. Truckai requested that the Examiner cancel the apparatus claims (including claim 31) 

“without prejudice.” J.A. 40453. 

Looking at the prosecution history as a whole, we agree 

with Hologic that this 2002 cancelation in response to the 

Examiner’s restriction requirement says nothing, implicitly or explicitly, about the patentability of claim 31. Put 

another way, Mr. Truckai canceled claim 31 for reasons 

other than patentability. Indeed, an assignee would have 

understood that the restriction requirement and subsequent cancelation in response to the restriction requirement meant that the patent applicant could later prosecute 

claim 31’s subject matter. This is because non-elected 

claims are “withdrawn from further consideration by the 

examiner,” 37 C.F.R. § 1.142(b), and there is no final patentability determination for those withdrawn claims (even 

if the restriction requirement comes after an office action 

on the merits), see id. § 1.142(a); see also Manual of Patent 

Examining Procedure (MPEP) § 810 (explaining that a restriction requirement is distinct from an office action on the 

merits). Rather, an applicant who has canceled a claim in 

response to a restriction requirement can file a divisional 

application with the non-elected claims and proceed separately with prosecution on the merits of those claims. See

35 U.S.C. § 121 (explaining that “the other invention [can 

be] made the subject of a divisional application”); MPEP 

§ 201.06 (“A divisional application is often filed as a result 

of a restriction requirement made by the examiner.”). A 

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claim canceled in response to a restriction requirement 

thus travels with the application.

Accordingly, we disagree with Minerva’s suggestion 

that claim 31, once canceled, could not be assigned, and 

that cancelation of claim 31 was some sort of concession 

that the claim was unpatentable. Although claim 31 was 

canceled for purposes of further prosecution of the ’072 application, cancelation did not nullify the claim, as it remained viable for further prosecution in a divisional 

application filed by whomsoever owned the ’072 application. A claim canceled in response to a restriction requirement is no less a viable claim just because of its cancelation 

in response to a restriction requirement. The 2004 assignment assigned not just the rights to the ’072 application, 

but also the rights to any continuation, continuation-inpart, or divisional patent applications not yet filed. For 

certain, canceled claim 31 traveled with the ’072 application and its assignment to Hologic. Mr. Truckai signed an 

oath when presenting the ’072 application, in which he 

stated his implicit good-faith belief that the claims in the 

application are patentable and would result in a valid patent. See Hologic III, 141 S. Ct. at 2309 n.3. The representations in that oath were further reaffirmed twice: First, 

by Mr. Truckai successfully defending claim 31 from the 

Examiner’s anticipation rejection before its cancelation, 

and second, by the 2004 assignment, in which the assignor 

warranted that it had “no present knowledge from which it 

could reasonably conclude” that these assigned intellectual 

property rights were invalid or unenforceable. J.A. 36367 

¶ 3.9(e). Therefore, Mr. Truckai represented (whether implicitly or explicitly) that the subject matter of claim 31 

was not invalid.3 

3 Our holding in this regard is limited to the facts of 

this case. We do not address whether a claim canceled for 

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12 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

II

Having determined that the 2004 assignment included 

a warranty as to claim 31’s validity, we turn now to the 

question of whether claim 1 of the ’348 patent is “materially 

broader” than claim 31 of the ’072 application. This requires us to construe the assigned and issued claims and 

compare the properly construed claims, focusing on the material aspects of those claims. Because this determination 

rests on principles of claim construction, it is ultimately a 

question of law we review de novo where, as here, it is decided only on the intrinsic evidence. Teva Pharms. USA, 

Inc. v. Sandoz, Inc., 574 U.S. 318, 331 (2015). 

The parties have significantly narrowed the question 

before us on remand, agreeing on which assigned and new 

claims to compare and also agreeing on what would make 

the new claim “materially broader” than the assigned 

claim. Specifically, the parties agree: (1) that we need only 

compare claim 1 of the ’348 patent to claim 31 of the 

’072 application (the parties did not identify any other assigned claims relevant to this question); and (2) that 

whether claim 1 is “materially broader” (rather than just 

broader) than claim 31 depends on the difference between 

moisture-permeable and moisture-impermeable devices.4 

We previously held that claim 1 broadly covers moistureimpermeable devices. See Hologic II, 957 F.3d at 1269–70 

(adopting district court’s construction of “applicator head” 

and rejecting Minerva’s construction requiring the claimed 

applicator head be moisture permeable); Cross-Appellant’s 

Suppl. Br. 3 (conceding that claim 1 has been construed “to 

cover devices with moisture impermeable applicator 

reasons other than to comply with a restriction requirement would be part of the 2004 assignment. 4 Given this agreement, we need not in this case define the line between broader claims and materially 

broader claims.

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heads”). Thus, if claim 31 is limited to moisture-permeable 

devices, the parties agree that claim 1 is “materially 

broader” and assignor estoppel would not bar Minerva from 

asserting its invalidity defenses. Claims 1 and 31 are reproduced in relevant part below: 

’348 patent claim 1 ’072 application claim 31

1. A device for treating a 

uterus comprising:

an elongate member having a proximal portion and 

a distal portion, the elongate member comprising 

an outer sleeve and an inner sleeve slidably and coaxially disposed within the 

outer sleeve;

an applicator head coupled 

to the distal portion, the 

applicator head defining an 

interior volume and having 

a contracted state and an 

expanded state, the contracted state being configured for transcervical 

insertion and the expanded 

state being configured to 

conform to the shape of the 

uterus, the applicator head 

including one or more electrodes for ablating endometrial lining tissue of the 

uterus; . . . 

31. An ablation and/or coagulation apparatus for 

use in delivering energy to 

tissue for ablation, the apparatus comprising:

an elongate member;

a deployment mechanism 

carried by the elongate 

member, the deployment 

mechanism moveable between a retracted position 

and a plurality of laterally 

expanded positions; 

an electrode array carried 

by the deployment mechanism;

a sheath slidably disposed 

over the electrode array; . . . 

’348 patent col. 19 ll. 9–42; J.A. 40362 (emphasis added to 

disputed limitation). 

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At the outset, Minerva and Hologic agree that claim 31 

does not have an express moisture-permeability limitation. 

Cross-Appellant’s Suppl. Br. 4; Appellants’ Suppl. Resp. 

Br. 2. Thus, there is no dispute that the plain claim language—the starting point of any claim construction analysis, Phillips v. AWH Corp., 415 F.3d 1303, 1312–14 (Fed. 

Cir. 2005)—suggests that claim 31 is not limited to moisture-permeable devices. Rather, the plain claim language 

is broad enough to encompass moisture-impermeable devices as well. 

Minerva nevertheless argues that claim 31 cannot 

cover a moisture-impermeable device. First, Minerva focuses on the lack of an “applicator head” limitation in 

claim 31, arguing that the claim therefore does “not cover 

a device with a moisture impermeable applicator head.” 

Cross-Appellant’s Suppl. Br. 6. We disagree. Claim 31 is 

an open-ended “comprising” claim. That claim 31 does not 

have an applicator head limitation supports the opposite 

conclusion: that the claim broadly covers both moisturepermeable and -impermeable applicator heads. 

Second, Minerva argues that the term “‘electrode array’ 

requires a material that is moisture permeable”—i.e., the 

claimed ablation device is moisture-permeable because it 

has a moisture-permeable electrode array. Cross-Appellant’s Suppl. Br. 8. We disagree, as nothing in the intrinsic 

record supports limiting claim 31 in the way Minerva 

urges. In fact, the principle of claim differentiation supports the opposite conclusion. Claim 1 of the ’072 application, for example, recited “an ablation device including an 

electrode array,” with “the electrode array including a fluid 

permeable elastic member.” J.A. 40357. It also recited 

“permitting moisture generated during the dehydration . . . 

to pass into the electrode carrying member.” Id. In other 

words, it expressly recited moisture permeability. 

Claim 16 likewise recited a fluid-permeable electrode array. See J.A. 40359–60 (“an electrode array carried by an 

elongate member, the array including a fluid permeable 

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elastic member”). This shows that Mr. Truckai and the 

other inventors knew how to draft claims that require 

moisture permeability. The fact that they chose not to include this limitation in claim 31, unlike claims 1 and 16, 

indicates that they did not intend to so limit that claim. 

See Phillips, 415 F.3d at 1314 (“Differences among claims 

can also be a useful guide in understanding the meaning of 

particular claim terms.”). 

Minerva also emphasizes the written description’s disclosure of an embodiment that has “an array of electrodes

formed on the surface of [an] electrode carrying means” 

that is “permeable to moisture,” arguing that claim 31 is 

therefore limited to a moisture-permeable device. CrossAppellant’s Suppl. Br. 7 (quoting ’348 patent5 col. 4 

ll. 58–61, col. 5 ll. 52–61). To be sure, the cited portion of 

the written description does reference a moisture-permeable electrode array. But this description of the “electrode 

carrying means” refers merely to “preferabl[e]” characteristics, including permeability “and/or a tendency to absorb 

moisture.” ’348 patent col. 5 ll. 52–61. It is not described 

as a required or mandatory characteristic. Accordingly, it 

is improper to restrict claim 31 to this “preferable” characteristic. See Comaper Corp. v. Antec, Inc., 596 F.3d 1343, 

1348 (Fed. Cir. 2010) (explaining that we do not “limit[] 

claims to a preferred embodiment”); InterDigital 

Commc’ns, LLC v. Int’l Trade Comm’n, 690 F.3d 1318, 

1328 (Fed. Cir. 2012) (“Because we conclude that the claim 

language is broad enough to include both embodiments, the 

inventors’ failure to include a reference to the alternative 

5 Neither party has cited or relied on the ’072 application’s written description as filed, nor have they identified any material differences between the ’072 application’s 

and ’348 patent’s written description. For simplicity, we, 

like the parties, rely on the ’348 patent’s written description in construing claim 31. 

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16 HOLOGIC, INC. v. MINERVA SURGICAL, INC. 

embodiment in the specification does not justify excluding 

that embodiment from the coverage of the claims.”). 

We acknowledge here, as we did in Hologic II, that the 

written description “emphasizes the importance of moisture removal,” 957 F.3d at 1269, as reflected in Minerva’s 

citations to descriptions of moisture removal and permeability in the ’348 patent written description, Cross-Appellant’s Suppl. Br. 7–8. After considering the intrinsic record 

as a whole, however, we disagree with Minerva’s assertion 

that claim 31 is limited to a moisture-permeable device. 

Accordingly, we hold that claim 1 of the ’348 patent is not 

materially broader than claim 31 of the ’072 application. 

* * * 

As we explained in Hologic II, “Minerva disputed none 

of the pertinent facts” concerning assignor estoppel at the 

district court or on appeal, including: (1) that Mr. Truckai 

executed a broad assignment of his patent rights to NovaCept and later sold NovaCept to Hologic’s predecessor; 

(2) that NovaCept received appreciable value for those patent rights; (3) that Mr. Truckai founded Minerva and used 

his expertise to research, develop, and obtain FDA approval for Minerva’s EAS; (4) that his job responsibilities 

included bringing the EAS to market to compete with Hologic; and (5) that he is in privity with Minerva. 957 F.3d 

at 1268. Thus, in view of our determination that claim 1 of 

the ’348 patent is not materially broader than claim 31 of 

the ’072 application, we conclude that the district court did 

not abuse its discretion in applying the doctrine of assignor 

estoppel. We thus affirm the district court’s summary 

judgment of no invalidity as to claim 1 of the ’348 patent. 

CONCLUSION

We have considered Minerva’s remaining arguments 

and find them unpersuasive. For the foregoing reasons, we 

hold that Minerva is estopped from challenging the validity 

of the ’348 patent claims based on the doctrine of assignor 

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estoppel. We therefore affirm the district court’s summary 

judgment that claim 1 of the ’348 patent is not invalid. 

Many portions of our earlier judgment were unaffected 

by the Supreme Court’s vacate and remand. We therefore 

reinstate our earlier judgment (1) affirming the district 

court’s denial of Hologic’s motions for a permanent injunction, enhanced damages, and ongoing royalties for infringement of the asserted claims of U.S. Patent No. 6,827,183; 

(2) affirming the district court’s summary judgment of infringement of claim 1 of the ’348 patent; (3) affirming the 

district court’s denial of Hologic’s requests for supplemental damages and for increased and enhanced supplemental damages; and (4) vacating the district court’s 

award of pre-and post-judgment interest on the supplemental-damages award and remanding with instructions 

to calculate the interest award in accordance with Hologic II. 

AFFIRMED-IN-PART, VACATED-IN-PART, AND 

REMANDED

COSTS

No costs. 

Case: 19-2054 Document: 106 Page: 17 Filed: 08/11/2022