disclaimer Archives

Prosecution Disclaimer Alive and Well, Especially in Closed Claim

by Hannah Hurley | Apr 17, 2025 | Patents

The US Court of Appeals for the Federal Circuit affirmed a district court’s noninfringement determination, finding that the presence of a disclaimed compound in the accused product precluded infringement. Azurity Pharm., Inc. v. Alkem Lab’ys Ltd., Case No. 23-1977 (Fed. Cir. Apr. 8, 2025) (Moore, Chen, Murphy, JJ.)

Azurity owns a patent directed to a nonsterile, stable liquid formulation of vancomycin hydrochloride, specifically designed for oral administration to treat Clostridium difficile infections. Following Alkem’s submission of an Abbreviated New Drug Application (ANDA), Azurity brought a Hatch-Waxman Act claim against Alkem for infringement of certain claims of the patent. The district court found that Azurity had disclaimed the presence of propylene glycol in the claimed formulation during the prosecution. Since Alkem’s ANDA product contained propylene glycol, the district court held that it did not infringe. Azurity appealed.

The Federal Circuit affirmed, focusing on the patent’s prosecution history and noting that Azurity used the lack of propylene glycol to distinguish its claimed invention from the prior art. The Court noted that this distinction was made during prosecution multiple times in response to the examiner’s rejections, and that Azurity had added negative claim limitations that specifically omitted propylene glycol from the scope of the claims.

The Federal Circuit also noted that Azurity used a “consisting of” transitional phrase to narrow the claims and relied on the closed transition to overcome the prior art. The Court explained that “consisting of” is a closed transition that limits the claim scope to only the recited components. By using this transition and not including propylene glycol as one of the claim components, Azurity effectively disclaimed propylene glycol from the invention. Therefore, the Court found that omission of propylene glycol during patent prosecution was “clean, unambiguous, and complete.”

Azurity argued that a pretrial stipulation between the parties, which stated that “[s]uitable flavoring agents for use in the asserted claims include flavoring agents with or without propylene glycol,” should preclude the application of the disclaimer. The Federal Circuit did not find this argument persuasive, concluding that the stipulation did not alter the clear and unambiguous disclaimer made during prosecution, nor did it affect the noninfringement finding. Since Alkem’s ANDA product contained propylene glycol and Azurity disclaimed inclusion of propylene glycol, there was no infringement.

Espresso Yourself: When Prosecution History as a Whole Doesn’t Demonstrate Clear, Unmistakable Disclaimer

by Katherine Pappas | Jan 4, 2024 | Patents

The US Court of Appeals for the Federal Circuit reversed and remanded a district court’s claim construction and related summary judgment rulings after determining that the district court erred in construing a claim term by improperly limiting the plain and ordinary meaning of the term. K-fee System GmbH v. Nespresso USA, Inc., Case No. 22-2042 (Fed. Cir. Dec. 26, 2023) (Taranto, Clevenger, Stoll, JJ.)

K-fee filed a lawsuit against Nespresso alleging infringement of three K-fee patents directed toward coffee machine portion capsules that use a barcode. The district court issued a claim construction order construing the term “barcode,” which was present in every asserted claim. In the claim construction order, the district court characterized the dispute as “whether statements made by K-fee System GmbH . . . before the EPO [European Patent Office] concerning the meaning of ‘barcode’ should influence the plain and ordinary meaning of that limitation in these proceedings.”

In the EPO, Nespresso’s foreign affiliate had challenged the validity of K-fee’s related European patent, and K-fee had responded seeking to distinguish a particular piece of prior art (Jarisch/D1). Because the statements made to the EPO were submitted to the US Patent & Trademark Office during prosecution of the asserted patents, the district court analyzed the statements as part of the intrinsic record. The district court concluded that K-fee had “argued strenuously before the EPO for a particular ‘plain and ordinary meaning,’ which excluded ‘bit codes’—codes made up of two binary symbols.” Based on the EPO submissions, the district court construed the claim term “barcode” to:

its plain and ordinary meaning (i.e., a code having bars of variable width, which includes the lines and gaps), the scope of which is understood by the clear and unequivocal statements K-fee made to the EPO (i.e., the scope of barcode does not include the type of bit code disclosed in Jarisch/D1).

Based on that construction of “barcode,” Nespresso moved for summary judgment of noninfringement. It argued that its accused products operated identically to Jarisch capsules, which K-fee distinguished before the EPO, since both use a machine-readable code with only two binary symbols. The district court agreed. When applying its construction at summary judgment, the district court clarified that using “the type of bit code disclosed in Jarisch” … means “a binary code containing only ‘0s’ and ‘1s.’” Thus, the district court read K-fee’s EPO statements “to mean that a barcode must ‘contain more than only two binary symbols’ and, by extension, that any code that contains only two binary symbols could not be a barcode.” Because the court found that “there was no dispute that Nespresso’s accused products used a code having only two symbols,” it granted Nespresso’s motion for summary judgment of noninfringement. K-fee appealed.

Considering the issue de novo, the Federal Circuit reviewed K-fee’s statements to the EPO in context and disagreed “that the ordinary meaning of ‘barcode’ excludes ‘bit codes’ (in some sense, two-value codes) or even bit codes of ‘the type . . . disclosed in Jarisch’ to [...]

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Disclaiming Claim Scope: Could the Patentee Have Anticipated This?

by Jake B. Vallen | Apr 6, 2023 | Patents

In the most recent decision in the Apple/VirnetX saga, the US Court of Appeals for the Federal Circuit affirmed a remand ruling from the Patent Trial & Appeal Board finding the challenged claims of VirnetX’s patents unpatentable. VirnetX Inc. v. Mangrove Partners Master Fund, Ltd., Case No. 2020-2271 (Fed. Cir. Mar. 30, 2023) (Moore, C.J.; Hughes, Stark, JJ.) (nonprecedential).

VirnetX owns two patents relating to a “secure mechanism for communicating over the internet.” The patents relate to a system in which a DNS module “intercepts . . . and determines whether [a] request is for a secure site.” The system creates a VPN if the proxy determines that the request is for a secure site. If the proxy determines that the request is not for a secure site, it forwards the request to a conventional DNS.

Mangrove, Apple and Black Swamp (collectively, Mangrove) petitioned for inter partes review (IPR) challenging various claims of the patents. The Board found that all the challenged claims were unpatentable as anticipated by Kiuchi or obvious in view of Kiuchi and other references. VirnetX appealed to the Federal Circuit (Mangrove Appeal). In that appeal, the Federal Circuit determined that, contrary to the Board’s finding, when VirnetX distinguished Aventail during reexamination of one of the patents, VirnetX disclaimed “a system in which a client computer communicates with an intermediate server via a singular, point-to-point connection.” As a consequence of the prosecution disclaimer, the Court found that the claims “require[s] direct communication between the client and target computers.” The Court vacated the Board’s decision and remanded the case for the Board to determine further factual questions regarding Kiuchi because “substantial evidence does not support the Board’s finding that the C-HTTP name server of Kiuchi performs the functions of the claimed DNS proxy module.”

Following the Mangrove Appeal, the Board again found that Kiuchi—the only prior art reference at issue in the present appeal—discloses a “secure network” for the transfer of patient information in a hospital setting and teaches a “direct-communication VPN between the client and target.” As a result, the Board concluded that Kiuchi anticipates all the challenged claims. VirnetX again appealed.

The Federal Circuit first addressed the Board’s conclusion that “Kiuchi teaches a direct-communication VPN and is therefore within the scope of the claims of VirnetX’s … patent, and not an indirect-communication VPN, which would have brought Kiuchi within the scope of VirnetX’s disclaimer.” The Court agreed with the Board that “Kiuchi discloses direct communication that satisfies the claimed VPN.” Specifically, “Kiuchi’s user agent does not communicate with the client-side proxy using a singular, point-to-point connection because the user agent addresses the desired endpoint, and the VPN provides the required message routing for the user agent to receive a response from the desired endpoint.” Moreover, the Court reasoned that Kiuchi’s proxy servers forward data packets and that Kiuchi teaches “the ability to address data to a particular computer,” consistent with the scope of the claims.

Next, the Federal Circuit addressed the Board’s [...]

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