Opinions — Friday, March 6, 2026

The Federal Circuit affirmed the District of Delaware's grant of judgment as a matter of law of no infringement of U.S. Patent Nos. 10,039,483 and 9,855,001, which Magnolia Medical Technologies, Inc. asserted against Kurin, Inc.'s blood sequestration device. Following a jury verdict for Magnolia on the '483 patent, the district court granted Kurin's post-trial JMOL, concluding that claim 1's separately recited "vent" and "seal member" limitations require two distinct structures under Becton, Dickinson & Co. v. Tyco Healthcare Group, LP, 616 F.3d 1249 (Fed. Cir. 2010), but that Kurin's accused device employed a single porous plug that functions as both vent and seal at different times. The court rejected Magnolia's challenge that this separate-structure requirement constituted an impermissibly late claim construction, holding that the district court merely clarified what was inherent in the plain and ordinary meaning when claim limitations are separately listed. As to the '001 patent, the court upheld the district court's determination that the term "diverter" invoked means-plus-function treatment under 35 U.S.C. § 112(f), which led to a stipulated judgment of no infringement because Kurin's device admittedly lacked the corresponding structure disclosed in the specification.

The decision reinforces Becton's principle that separately listed claim elements carry a "clear implication" of structural distinctness as a matter of plain meaning, even absent explicit claim construction proceedings. The court clarified that applying this structural separateness principle post-verdict does not constitute impermissible new claim construction but rather permissible elaboration on what the plain language already required, citing Cordis Corp. v. Boston Scientific Corp., 658 F.3d 1347 (Fed. Cir. 2011). This holding confirms that patentees bear the burden of presenting infringement theories consistent with the separate-structure implication from the outset when claims list multiple components discretely. The decision signals that district courts retain authority to apply Becton at the JMOL stage when the structural separateness question was not explicitly briefed during claim construction, placing greater pressure on parties to anticipate and address such structural distinctions earlier in litigation, particularly where accused devices employ multifunctional components that sequentially perform the functions of separately recited claim elements.

The Federal Circuit reversed the Western District of Texas's exclusion of Exafer Ltd.'s damages expert testimony and vacated summary judgment of no remedy in Exafer's patent infringement suit against Microsoft Corporation concerning U.S. Patent Nos. 8,325,733 and 8,971,335, which relate to optimizing data flows in virtual networks. Microsoft accused Exafer's damages expert of using an improper royalty base by calculating damages based on virtual machine hours (VM-hours) rather than the accused SmartNIC and VFP Fastpath features themselves. The district court excluded the expert under Federal Rule of Evidence 702, reasoning that Enplas Display Device Corp. v. Seoul Semiconductor Co., 909 F.3d 398 (Fed. Cir. 2018), barred using unaccused products as a royalty base. The Federal Circuit held that the district court misapplied Enplas by creating an overbroad categorical rule against using unaccused products in damages calculations. Unlike in Enplas, where the unaccused products lacked causal connection to infringement, Exafer's expert established that the accused features enabled Microsoft to host additional VMs by reducing CPU usage, creating a legally sufficient nexus between the patented technology and the VM-hour metric. The court emphasized that reasonable royalty calculations are highly fact-specific and that unaccused products may properly serve as a royalty base when causally connected to the accused technology's value.

This decision clarifies the boundaries of Enplas and rejects its interpretation as a per se prohibition on damages theories incorporating unaccused products. The opinion emphasizes that patent damages analysis must assess causal relationships between claimed inventions and downstream commercial benefits on a case-by-case basis, particularly where the patented technology creates measurable infrastructure efficiencies that translate to quantifiable business advantages. The holding has particular significance for process patents and enabling technologies where the direct accused instrumentality differs from the commercial product through which value manifests. By approving a damages theory tethered to incremental VM capacity rather than the accused network components themselves, the court signals receptiveness to sophisticated economic modeling that traces the patented invention's contribution through multiple technical layers, provided expert testimony establishes the causal chain with sufficient reliability under Rule 702.

The Federal Circuit affirmed the Patent Trial and Appeal Board's rejection of claims in HBN Shoe, LLC's patent application for a cleated athletic shoe designed to permit plantarflexion and eversion of the wearer's foot during weight-bearing exercise. The examiner found claim 1 obvious over Auger (disclosing most structural features including a concave depression) and Yoshida (teaching location of the depression beneath the first metatarsal head to facilitate joint flexion), and the Board affirmed, finding substantial evidence supported the conclusion that the modified Auger-Yoshida structure met all claim limitations including the "configured to permit" language.

The court's analysis centered on whether the "configured to permit [plantarflexion and eversion]" limitation imposed structural requirements beyond mere capability, with HBN invoking Aspex Eyewear to argue for an intended-design construction. The court found no claim construction error because HBN never requested an Aspex-based construction before the Board, instead arguing the prior art was "incapable" of performing the function due to size limitations—a factual assertion the Board permissibly rejected as unsupported. The court also deferred to the Board's credibility determination regarding the coinventor's declaration, which contradicted the inventor's earlier published work, and rejected HBN's arguments that the Board improperly conflated shoe flexibility with foot flexibility or relied on hindsight, finding the Board properly identified motivation to combine rooted in the references themselves.