IP UPDATE
Exploring the latest in intellectual property law
IP UPDATE
Exploring the latest in intellectual property law
doctrine of equivalents
Subscribe to doctrine of equivalents's Posts

Identical or not? Jury can’t decide issues of claim construction

by | Aug 21, 2025 |

The US Court of Appeals for the Federal Circuit reversed a district court’s denial of a motion for judgment as a matter of law (JMOL) of noninfringement, finding that the jury’s infringement findings were unsupported by sufficient evidence and that the district court had improperly delegated claim construction to the jury. Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC, Case No. 23-2350 (Fed. Cir. Aug. 13, 2025) (Lourie, Dyk, Cunningham, JJ.)

Laboratory Corp. of America Holdings (LabCorp) holds two patents with substantially overlapping specifications, both generally directed to methods for preparing DNA samples for sequencing and enrichment techniques aimed at enabling whole-genome sequencing. LabCorp initiated litigation alleging that various Qiagen Sciences kits containing materials used in DNA sample preparation for sequencing infringed its patents. During claim construction, the district court construed several patent terms as follows:

  • In the first patent, “second target-specific primer” means a single-stranded oligonucleotide with a 3’ portion that specifically anneals to a portion of the known target nucleotide sequence in the amplicon from step (b), and a 5’ portion identical to a second sequencing primer.
  • Also in the first patent, “second adaptor primer” refers to a nucleic acid molecule containing a sequence identical to part of the first sequencing primer and nested relative to the first adaptor primer.
  • In the second patent, “target-specific primer” is defined as a primer sufficiently complementary to the target to enable selective annealing and amplification, without amplifying non-target sequences in the sample.

The jury found that Qiagen infringed the first patent under the doctrine of equivalents and willfully and literally infringed the second patent. The jury awarded damages accordingly. The district court denied Qiagen’s renewed motion for JMOL to reverse the damages and the jury’s findings of infringement and validity, and its alternative request for a new trial. Qiagen appealed.

Qiagen raised two noninfringement arguments regarding the first patent, and the Federal Circuit agreed with both. First, the Court held that it was error to allow the jury to apply “plain meaning” and equate a sequence being “identical to another” with being “identical to a portion” of another. Specifically, Qiagen’s accused second target-specific primer (Sample Index Primer, or SIP) was 19 nucleotides long while the second sequencing primer (Read2 primer) was 34 nucleotides. The fact that they shared an overlapping sequence did not make them identical.

Although the district court had treated “identical” as a factual issue for the jury, the Federal Circuit, citing its 2008 decision in O2 Micro Int’l Ltd. v. Beyond Innovation Tech., found that this was a claim construction matter that should not have been left to the jury. The term “identical” must be given its full meaning under claim construction and cannot be interpreted as “identical to a portion.” The Court emphasized that the specification and claims distinguished between full and partial identity: The second target-specific primer must be “identical to” the second sequencing primer while the adaptor primer need only be “identical to a portion” of the first sequencing primer. This difference [...]

Continue Reading



read more

Valve turned: Prosecution history estoppel applies to closely related claims

by | Jul 24, 2025 |

The US Court of Appeals for the Federal Circuit reversed a jury’s infringement finding, concluding it was precluded by prosecution history estoppel. Colibri Heart Valve LLC v. Medtronic CoreValve LLC, Case No. 23-2153 (Fed. Cir. July 18, 2025) (Taranto, Hughes, Stoll, JJ.)

Colibri Heart Valve sued Medtronic CoreValve for infringing a patent covering a method of implanting an artificial heart valve. At trial, the district court denied Medtronic’s motion for judgment as a matter of law, allowing the jury to consider Colibri’s infringement theory under the doctrine of equivalents. The jury found in Colibri’s favor. Medtronic appealed.

The Federal Circuit reversed, finding that Colibri was estopped from asserting its equivalents theory. During prosecution, Colibri had canceled a claim that explicitly recited “retracting the movable sheath.” The asserted claim, while using different language, involved a similar concept: “pressing against the pusher member with a force that moves the pusher member outward from the moveable sheath.” The Court concluded that a skilled artisan would recognize these limitations as equivalent in light of basic physics.

Citing the Supreme Court’s 2002 Festo v. Shoketsu decision, the Federal Circuit emphasized that prosecution history estoppel can arise not only from formal amendments but also from the cancellation of closely related claims. Here, the cancellation of one claim effectively narrowed the scope of the remaining claims, triggering estoppel.

Accordingly, the Federal Circuit reversed the district court’s denial of judgment of noninfringement.



read more

Equivalence Requires Element-by-Element Proof With Linking Argument

by | Nov 7, 2024 |

The US Court of Appeals for the Federal Circuit affirmed a district court determination that a patent owner had not provided the “particularized testimony and linking argument” required to demonstrate equivalence under the doctrine of equivalents. NexStep, Inc. v. Comcast Cable Commc’ns, LLC, Case No. 2022-1815 (Fed. Cir. Oct. 24, 2024) (Chen, Taranto, JJ.) (Reyna, J., concurring in part and dissenting in part). In his dissent, Judge Reyna criticized the majority for ignoring the totality of the evidence presented by the patent owner and imposing a new rule requiring patentees to always present expert testimony to prove infringement under the doctrine of equivalents.

NexStep owns a patent directed to a “concierge device” for assisting users with obtaining customer support for smart devices. The claims are directed to a concierge device that initiates a technical support session in response to “a single action” (i.e., a single button press) by a user. After the claimed “single action,” the concierge device conveys consumer device identification information for the product at issue, identifies an appropriate technical support team for the product, and causes the home gateway to initiate a support session for the device and forward the consumer device information during the session.

NexStep sued Comcast for patent infringement, asserting that three tools in Comcast’s mobile smartphone application infringed the concierge device patent: Xfinity Assistant, Troubleshooting Card, and Diagnostic Check. Each of these tools assists users with troubleshooting a given device in response to the user pressing a series of buttons on a smartphone’s display. At trial, NexStep argued that pressing a series of buttons literally met the single action limitation because a single action could comprise a series of steps. By way of illustration, NexStep’s expert explained that throwing a baseball – a single action – required multiple steps: “[W]hen you throw a baseball, you pick it up, you orient it, you get it in your palm, you throw it.”

The jury returned a verdict of no literal infringement but found infringement under the doctrine of equivalents. Comcast moved for judgment as a matter of law, which the district court granted after finding that NexStep had failed to offer the “particularized testimony and linking argument” required to demonstrate equivalence. NexStep appealed.

The Federal Circuit emphasized that the doctrine of equivalents provides a “limited exception” to the principle that the claim defines the scope of the patentee’s exclusivity rights, and that a finding under the doctrine of equivalents is “exceptional.” To guard against overbroad applications of this exception, the Court’s precedent imposes specific evidentiary requirements necessary to prove infringement under the doctrine. The patent owner must provide proof on an element-by-element basis and from the perspective of someone skilled in the art, “for example through testimony of experts or others versed in the technology; by documents . . . and . . . by the disclosures of the prior art.” Finally, the patent owner must provide “particularized testimony and linking argument as to the insubstantiality of the differences between the claimed invention and the [...]

Continue Reading



read more

When It Comes to Claim Construction, Prosecution History and Specification Rule

by | Feb 23, 2023 |

Addressing claim constructions across two patents that ultimately led to noninfringement findings by a district court, the US Court of Appeals for the Federal Circuit affirmed one construction because it was supported by the prosecution history but reversed another because it was unsupported by the specification. SSI Techs., LLC v. Dongguan Zhengyang Elec. Mech. Ltd., Case Nos. 21-2345, 22-1039 (Fed. Cir. Feb. 13, 2023) (Reyna, Bryson, Cunningham, JJ.)

SSI owns two patents directed to sensors for determining the characteristics of fluid in a container such as a fuel tank. One patent, referred to as the transducer patent, describes an exemplary sensor system containing a “level” transducer and a “quality” transducer. The two transducers use ultrasonic sound waves and time of flight to determine both a level of fluid in a given tank and a quality (i.e., concentration of diesel exhaust fluid). The other patent, referred to as the filter patent, describes a similar system but attempts to address the problem of erratic measurement results that may occur because of air bubbles embedded in the fluid. This patent claims a “filter” covering the sensing area that substantially prohibits gas bubbles from entering the sensing area.

Dongguan Zhengyang Electronic Mechanical (DZEM) produces systems that determine the quality and volume of diesel exhaust fluid that are used in emission-reduction systems for diesel truck engines. SSI accused DZEM of infringing both patents. In the district court action, DZEM brought a motion for summary judgment of noninfringement based on the court’s construction of certain terms that appear in the asserted claims. With reference to the transducer patent, the claims recite the need to “determine whether a contaminant exists in the fluid based on . . . a dilution of the fluid [] detected while the measured volume of the fluid decreases.” The district court determined that this claim element required that the contaminant determination actually consider the measured volume of the fluid. The district court predicated its determination on the prosecution history, having found that this term was amended to include the disputed term and that the applicant’s intention was to incorporate the specific error-detection capability recited in the specification. The parties had previously agreed that the DZEM products did not base the contamination determination on any consideration of the measured volume. As a result, the district court granted DZEM’s motion for summary judgment of noninfringement on the transducer patent.

Regarding the filter patent, the district court adopted DZEM’s construction of the term “filter,” which was “a porous structure defining openings, and configured to remove impurities larger than said openings from a liquid or gas passing through the structure.” DZEM’s accused sensors includes a rubber cover with four apertures. The district court found that the rubber cover was not “porous” because the apertures were “relatively large” when compared with the disclosed embodiments in the specification. As a result, the court granted DZEM’s motion for summary judgment of noninfringement on the filter patent. SSI appealed.

SSI challenged both constructions. Regarding the transducer patent, SSI argued that [...]

Continue Reading



read more

Nailed It: Expert Must at Least Meet Ordinary Skill Level to Testify from POSITA Perspective

by | Jan 27, 2022 |

Addressing a US International Trade Commission (ITC) decision finding a § 337 violation as to one patent but no violation as to four other patents, the US Court of Appeals for the Federal Circuit reiterated that a technical expert must at least meet the level of ordinary skill in the art of the asserted patents to testify from the perspective of a person of ordinary skill in the art (POSITA), whether for claim construction, validity or infringement. Kyocera Senco Indus. Tools Inc. v. ITC, Case Nos. 20-1046, -2050 (Fed. Cir. Jan. 21, 2022) (Moore, C.J.; Dyk, Cunningham, JJ.)

In 2017, Kyocera filed a complaint at the ITC seeking a § 337 investigation based on infringement allegations for six patents directed to battery-powered gas spring nail guns. The investigation was assigned to the Chief Administrative Law Judge (ALJ), who, in the context of a Markman order, adopted Koki Holdings America Ltd.’s uncontested level of skill in the art as including “experience in powered nailer design.” After claim construction, Kyocera dropped one patent from the investigation and went forward with infringement under the doctrine of equivalents as the sole basis for violation for four other patents.

Prior to the evidentiary hearing, Koki moved to exclude Kyocera’s expert’s testimony due to their admission during deposition that they did not have the experience in powered nailer design required by the adopted level of ordinary skill in the art. The Chief ALJ held that the Federal Circuit’s decision in AquaTex Indus. v. Techniche Sols. expressly required that Kyocera’s expert’s testimony be excluded as to infringement under the doctrine of equivalents but permitted the expert to testify as to literal infringement on one patent and on claim construction. After the evidentiary hearing, the Chief ALJ issued an initial determination that relied, in part, on Kyocera’s expert to find a particular element satisfied on the one remaining patent where literal infringement was asserted, but ultimately found no infringement due to other claim limitations. The Chief ALJ’s noninfringement decision as to the one remaining patent was then overturned on review by the full ITC, which found a § 337 violation and issued a limited exclusion order.

Kyocera appealed the Chief ALJ’s exclusion of its expert’s testimony on doctrine of equivalents, and Koki cross-appealed on the Chief ALJ’s decision to allow Kyocera’s expert to testify as to literal infringement and claim construction. The Federal Circuit reversed the ITC’s decision, holding that it was error to permit any infringement testimony from Kyocera’s expert and explaining that a witness must at least have ordinary skill in the art to offer testimony from the perspective of a skilled artisan for claim construction, validity or infringement, whether literal or under the doctrine of equivalents.

Alexander Ott was a member of Koki’s ITC trial team and the Federal Circuit appeal team in this case.



read more

Doctrine of Equivalents Analysis Should Not Be Simple Binary Comparison

by | Mar 17, 2021 |

The US Court of Appeals for the Federal Circuit remanded a district court’s claim construction and grant of a defendant’s summary judgment motion of non-infringement under the doctrine of equivalents, finding that a reasonable juror could find that the accused products performed substantially the same function in substantially the same way to achieve substantially the same result as the claimed invention. Edgewell Personal Care Brands, LLC v. Munchkin, Inc., Case No. 20-1203 (Fed. Cir. Mar. 9, 2021) (Moore, J.)

Edgewell manufactures and sells the “Diaper Genie,” a diaper pail system with a replaceable cassette placed inside the pail for soiled diaper collection, forming a wrapper around the diapers. Munchkin marketed a refill cassette as compatible with Edgewell’s pails. Edgewell’s two patents at issue relate to improvements in the cassette. After claim construction, Edgewell asserted literal infringement of one patent and infringement under the doctrine of equivalents of the other patent. The district court granted Munchkin’s summary judgment motion of non-infringement against both patents. Edgewell appealed.

Edgewell’s first patent is directed to a cassette with a clearance at its bottom portion. The claim construction dispute turned on whether the claims required a clearance space after the cassette was installed. The district court construed the claim to require a space and to require that the claimed “clearance” cannot be filled by an unclaimed interfering member. The district court granted Munchkin summary judgment because Munchkin’s refill cassette had no space after the cassette was installed. The Federal Circuit reversed, explaining that an “apparatus claim is generally to be construed according to what the apparatus is, not what the apparatus does.” The Court found that without an express limitation, “clearance” should be construed to cover all uses of the claimed cassette. The Court determined that the specification and purpose of the “clearance” supported the notion that the claim does not require a clearance after insertion.

The second patent is directed to a cassette with a cover that includes a “tear-off” section. The district court’s construction of an annular cover was of a single, ring-shaped cover. Munchkin’s cassettes each include a two-part cover, and the district court granted Munchkin’s motion for summary judgment of non-infringement. Although the Federal Circuit agreed with the claim constructions, the Court found that the district court erred in granting summary judgment to Munchkin under the doctrine of equivalents for claim element vitiation on the basis that “annular cover” and “tear-off” limitations §§would be rendered meaningless.

The vitiation doctrine ensures that applying the doctrine of equivalents “does not effectively eliminate a claim element in its entirety.” The Federal Circuit found that the district court erred in evaluating this element as a binary choice—single-component structure versus a multi-component structure. Instead, the Court explained that the district court should have evaluated the evidence to determine whether a reasonable juror could find that the accused products perform substantially the same function, in substantially the same way, achieving substantially the same result as the corresponding claim elements. Edgewell’s expert opined that Munchkin’s products performed the [...]

Continue Reading



read more

Court’s Drug Patent Prescription: Unclaimed Disclosure is Dedicated

by | May 19, 2020 |

Addressing the disclosure-dedication doctrine, the US Court of Appeals for the Federal Circuit concluded that the disclosure-dedication doctrine barred a patent owner’s claim of infringement under the doctrine of equivalents because the asserted patents disclose, but do not claim, the alleged equivalent. Eagle Pharmaceuticals Inc. v. Slayback Pharma LLC, Case No. 19-1924 (Fed. Cir. May 8, 2020) (Reyna, J.).

(more…)



read more

No Splitting the Die – Federal Circuit Affirms Summary Judgment of Noninfringement

by | Jan 8, 2020 |

A divided panel decision of the US Court of Appeals for the Federal Circuit affirmed a summary judgment of noninfringement, finding no disputed issues of material fact to preclude summary judgement. Plastic Omnium Advanced v. Donghee America, Inc., Case No. 2018-2087 (Fed. Cir., Nov. 21, 2019) (Reyna, J) (Clevenger, J, dissenting).

Plastic Omnium filed suit against Donghee for patent infringement of patents generally relating to manufacturing plastic fuel tanks formed by blow molding. A portion of this process, as claimed, requires “cutting and opening an extruded parison of closed cross section.” The primary dispute on appeal is the meaning of the claim term “parison.” In its claim construction order, the district court found the patentee had acted as its own lexicographer, defining the key disputed term “parison” as “referring to a plastic tube with a closed cross section that is shaped by—and has reached the end of—a die and is split either immediately upon exiting the die or at some point thereafter.” Following claim construction, the district court granted Donghee’s motion for summary judgment of noninfringement as to the asserted claims. Plastic Omnium appeals the grant of summary judgment under both literally infringement and infringement under the doctrine of equivalents.

(more…)



read more

BLOG EDITORS

Paul Devinsky

Amol Parikh

Jodi Benassi

STAY CONNECTED

Subscribe

TOPICS

ARCHIVES