The case involves Hologic, Inc. and Cytyc Surgical Products, LLC as plaintiffs-appellants against Minerva Surgical, Inc. as the defendant-cross-appellant, with appeals stemming from the U.S. District Court for Delaware. The United States Court of Appeals for the Federal Circuit received the case on remand from the Supreme Court, which vacated the previous judgment affirming the district court’s summary judgment that claim 1 of U.S. Patent No. 9,095,348 was not invalid based on assignor estoppel. The Supreme Court upheld the doctrine of assignor estoppel but noted its limitations, requiring the appellate court to evaluate whether claim 1 is 'materially broader' than claims assigned to Hologic.
The court determined that claim 1 is not 'materially broader' than the assigned claims, thereby affirming the district court's judgment and concluding that Minerva is estopped from contesting the validity of claim 1. The background of the dispute traces back to 1993 when Csaba Truckai co-founded NovaCept, developing the NovaSure endometrial ablation device. Truckai filed a patent application in 1998, which included various claims. After NovaCept was acquired by Cytyc in 2004, it assigned its intellectual property rights, warranting their validity. Truckai later founded Minerva in 2008, which developed a competing device, the Endometrial Ablation System, approved by the FDA in 2015.
Hologic acquired Cytyc in 2007 and currently holds the ’348 patent involved in this litigation, which was issued in 2015 and claims priority from the ’072 application through continuation and divisional applications. The ’348 patent describes an ablation device designed to address issues of steam and liquid buildup at the ablation site, a problem associated with prior art devices. Such moisture accumulation created a conductive path that hindered effective current flow to the tissue, leading to passive heating rather than targeted ablation. To combat moisture, the patent outlines devices that facilitate the active or passive removal of moisture during the ablation process.
The exemplary device consists of three components: an applicator head, a main body, and a handle. The applicator head features an electrode carrying means with an array of electrodes and is made from a non-conductive, moisture-permeable material. It also includes a deflecting mechanism, which shapes the electrode array into a triangular formation suitable for various uterine anatomies.
Claim 1 is the only asserted claim of the ’348 patent, with its breadth compared to claim 31 of the ’072 application being a focal point for analysis. In November 2015, Hologic initiated a lawsuit against Minerva for alleged infringement of the ’348 patent. Minerva countered with invalidity claims, including lack of enablement and written description. Hologic sought summary judgment based on assignor estoppel, which the district court granted, affirming the validity of the patent and the infringement of claim 1. Following a jury trial on willful infringement and damages, both parties appealed. In its cross-appeal, Minerva contested the assignor estoppel ruling and the district court's claim constructions. The Federal Circuit upheld the district court's application of assignor estoppel and affirmed the summary judgment of no invalidity.
The district court's interpretations of terms contested by Minerva were upheld, affirming the summary judgment of infringement. Minerva sought Supreme Court review, challenging the doctrine of assignor estoppel, claiming it lacked statutory support and urging the Court to reconsider its application. The Supreme Court granted certiorari, acknowledged the historical significance of assignor estoppel, but clarified it has limitations, applying only when an inventor’s statements during the assignment conflict with their litigation stance against the patent owner. The Court emphasized that assignor estoppel does not apply if the assignor has not made prior inconsistent representations regarding an invalidity defense. Minerva's argument that estoppel should not apply due to the materially broader nature of Hologic's new claims was deemed significant. The Court vacated the previous judgment and remanded the case to determine whether Hologic's new claim was indeed materially broader than the claims assigned by Mr. Truckai. On remand, the focus is on whether claim 1 of the ’348 patent is materially broader than claim 31 of the ’072 application, which was canceled before the 2004 assignment. Minerva contends that all claims at the time of the assignment included a moisture-permeability limitation, which claim 31 did not possess. It argues that since claim 31 was canceled before the assignment, it cannot be used to establish prior representations of validity. Furthermore, Minerva asserts that claim 31 does not cover moisture-impermeable devices and emphasizes that claim 1 encompasses both moisture-permeable and moisture-impermeable devices, making it materially broader.
Hologic asserts that Mr. Truckai warranted the validity of claim 31 during its assignment, despite its cancellation prior to the 2004 assignment. Hologic emphasizes that the cancellation was 'without prejudice' and in compliance with an Examiner's restriction requirement, suggesting that a patent practitioner could reintroduce the claim in future applications. They highlight that the Examiner had previously allowed claim 31 on its merits before its cancellation. Hologic argues that claim 1 is not materially broader than claim 31, as both lack moisture-permeability limitations. The key issues are whether Mr. Truckai warranted claim 31's validity at the time of the assignment, considering the implications of its 2002 cancellation, and whether claim 31 is materially broader than claim 1, particularly regarding its applicability to moisture-impermeable devices.
The analysis begins with the examination of the 2004 assignment's context concerning the prosecution history of the ’072 application. Mr. Truckai and co-inventors filed the application on June 23, 1998, with 31 claims. Claim 31 faced an initial rejection for anticipation under 35 U.S.C. 102, but Mr. Truckai successfully argued for its allowance in October 2000. On May 21, 2001, the Examiner issued a restriction requirement, indicating that claim 31 was distinct from other claims, leading to Mr. Truckai electing to pursue method claims further. Following this, Mr. Truckai requested the cancellation of apparatus claims, including claim 31, without prejudice on February 28, 2002. The overall prosecution history indicates that the cancellation was not related to patentability concerns, suggesting that an assignee would recognize the opportunity to pursue claim 31 later.
Non-elected claims are not subject to final patentability determinations as they are withdrawn from further consideration by the examiner under 37 C.F.R. 1.142(b). An applicant can file a divisional application for these claims, which remain viable even after cancellation in response to a restriction requirement. The 2004 assignment included rights to the ’072 application and any related continuation or divisional applications, meaning canceled claim 31 traveled with the application and its assignment to Hologic. Mr. Truckai's oath during the application process indicated a good-faith belief in the patentability of the claims, further supported by his defense of claim 31 against an anticipation rejection and the warranty in the 2004 assignment regarding the validity of the assigned intellectual property rights.
The next issue is whether claim 1 of the ’348 patent is "materially broader" than claim 31 of the ’072 application, which involves a legal question of claim construction based solely on intrinsic evidence. The parties have agreed to compare only claim 1 of the ’348 patent to claim 31 of the ’072 application, focusing on the difference between moisture-permeable and moisture-impermeable devices to determine if claim 1 is materially broader.
Claim 1 is established to broadly encompass moisture-impermeable devices, as supported by prior rulings (Hologic II, 957 F.3d at 1269–70), which rejected a moisture-permeable requirement for the applicator head. Consequently, if claim 31 were restricted to moisture-permeable devices, it would be materially narrower than claim 1, allowing Minerva to assert invalidity defenses without being hindered by assignor estoppel. Both parties concur that claim 31 does not explicitly require moisture permeability, and the language of the claim permits coverage of both moisture-permeable and moisture-impermeable devices.
Minerva's arguments against this interpretation focus on two points: the absence of an 'applicator head' limitation in claim 31 and the assertion that the 'electrode array' must be moisture-permeable. Both claims are countered by the open-ended nature of claim 31, which allows for a broader interpretation, incorporating various types of applicator heads. Furthermore, there is no intrinsic evidence supporting Minerva's moisture-permeability requirement for the electrode array. Claim differentiation principles suggest that since claims 1 and 16 specifically mention moisture permeability, the omission of such language in claim 31 indicates an intentional choice by the inventors not to impose this limitation.
Differences among claims offer insights into claim term meanings. Minerva argues that claim 31 is restricted to a moisture-permeable device based on the written description of a moisture-permeable electrode array. However, the relevant section merely describes permeability as a "preferable characteristic" and not a mandatory requirement. As established in Comaper Corp. v. Antec, Inc., claims cannot be limited to preferred embodiments. The claim language is interpreted to encompass both moisture-permeable and non-permeable devices, with the inventors' omission of an alternative embodiment not justifying exclusion. Although the written description highlights moisture removal's importance, it does not limit claim 31 accordingly.
Furthermore, the court finds that there is no significant difference between claim 1 of the ’348 patent and claim 31 of the ’072 application, leading to the conclusion that the district court properly applied assignor estoppel. Minerva did not contest key facts regarding the assignment of patent rights from Mr. Truckai to NovaCept, the value received, his role in establishing Minerva, and his connection to the company. Consequently, the court affirms the district court's summary judgment of no invalidity for claim 1 of the ’348 patent.
The remaining arguments from Minerva are deemed unpersuasive. The court reinstates its previous judgment, affirming the denial of Hologic's motions for permanent injunction, enhanced damages, and ongoing royalties, the summary judgment of infringement of claim 1 of the ’348 patent, and the denial of requests for supplemental damages. It vacates the district court’s interest award on supplemental damages and remands for recalculation in line with Hologic II. The judgment is affirmed in part, vacated in part, and remanded, with no costs awarded.
