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Exploring the Latest in Intellectual Property Law
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When it comes to objective criteria of nonobviousness, nexus is looser for license evidence

by | Jun 26, 2025 |

The US Court of Appeals for the Federal Circuit partially reversed a decision by the Patent Trial & Appeal Board, effectively relaxing the nexus requirements for patent licenses pertaining to their usage as objective indicia of nonobviousness. Ancora Technologies, Inc. v. Roku, Inc. et. al., Case Nos. 23-1674; -1701 (Fed. Cir. June 16, 2025) (Lourie, Reyna, Hughes, JJ.) (per curium).

Ancora owns a patent directed to limiting software use on a computer through license verification. The patented technology centers on storing an “agent,” which is a license verification program, in a computer’s basic input/output system (BIOS) rather than in volatile memory. In 2021, Nintendo, Roku, and VIZIO separately filed petitions for inter partes review (IPR) challenging claims of Ancora’s patent. The Board consolidated the proceedings and ultimately found certain claims of the patent unpatentable as obvious over a combination of two prior art references: Hellman (which discloses storing license information in nonvolatile memory) and Chou (which discloses a BIOS-level security routine). Ancora appealed.

Ancora raised three issues on appeal:

  • That the Board erred in construing the claim term “agent”
  • That even if the Board correctly construed “agent,” it nonetheless erred in determining obviousness under 35 U.S.C. § 103 based on a combination of Hellman and Chou
  • That the Board erred in its analysis of secondary considerations of nonobviousness.

The Federal Circuit affirmed the Board’s construction of “agent” to mean “a software program or routine” with no further limitations. The Court disagreed with Ancora’s argument that “agent” was limited to use in software only, primarily because neither the patent nor prosecution history provided any disclaimer of hardware. For similar reasons, the Court also disagreed with Ancora’s argument that “agent” was limited to use at the operating-system level.

On the obviousness determination, the Federal Circuit upheld the Board’s conclusion that the combination of Hellman and Chou rendered the claims prima facie obvious. The Court rejected Ancora’s argument that the Hellman/Chou combination would not provide motivation to combine since they are redundant.

The Federal Circuit disagreed with the Board’s analysis of the objective indicia of nonobviousness, particularly the treatment of Ancora’s licensing evidence. The Board found that Ancora failed to establish a sufficient nexus between the claimed invention and evidence of two objective indicia of nonobviousness: industry praise and licensing.

The Federal Circuit agreed with the Board on industry lack of nexus for the alleged praise (where the Board found that praise for the invention in a press release and an agreement between Ancora and another company offering products using the patent was directed broadly to the patent and not specifically to the challenged claims). However, the Court found that the Board erred regarding the appropriate nexus as it relates to Ancora’s licensing evidence.

The Board found that Ancora failed to show a nexus between the challenged claims and two licenses it obtained through settlement agreements in other cases. The Federal Circuit disagreed, finding that the Board applied an overly stringent nexus standard inconsistent with precedent. While products may require detailed [...]

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CRISPR Clarity: Enablement Is Analyzed Differently Under §§ 102 and 112

by | Jun 18, 2025 | ,

In a decision underscoring the distinct standards governing enablement under §§ 102 and 112, the US Court of Appeals for the Federal Circuit affirmed the Patent Trial & Appeal Board’s finding that a prior art reference was enabling for purposes of anticipation, even in the absence of working examples. Agilent Technologies, Inc. v. Synthego Corp., Case Nos. 23-2186; -2187 (Fed. Cir. June 11, 2025) (Prost, Linn, Reyna, JJ.)

The case centers on CRISPR, the gene-editing technology that has reshaped the frontiers of biology and biotechnology. Agilent owns patents that claim chemically modified guide RNAs (gRNAs) designed to improve stability and performance in CRISPR-Cas systems. Synthego filed an inter partes review (IPR) petition asserting that the patents were unpatentable. The Board found all claims unpatentable, relying on a 2014 publication by Pioneer Hi-Bred that disclosed similar modified gRNAs. Agilent appealed.

Agilent challenged the Board’s finding that the prior art was enabling, arguing that Pioneer Hi-Bred merely proposed a research plan without demonstrating which specific modifications would yield functional gRNAs. Agilent emphasized that the reference lacked working examples and disclosed numerous nonfunctional sequences, contending that a skilled artisan would not have been able to identify a successful embodiment without undue experimentation. It also argued that the nascent state of CRISPR technology in 2014 compounded the unpredictability, making the reference non-enabling. In support, Agilent relied heavily on the Supreme Court’s 2023 decision in Amgen v. Sanofi, where the Supreme Court invalidated a broad genus claim for failing to enable its full scope.

The Federal Circuit was not persuaded. The Court drew a clear distinction between enablement under § 112 (which governs patent validity) and enablement under § 102 (which governs anticipation). The Court explained that the bar is lower for the latter, and that a prior art reference need only enable a single embodiment within the scope of the claim. While Amgen involved § 112, the Court emphasized that this case turned on § 102, where the standard is less demanding.

The Federal Circuit grounded this distinction in both the statutory text and the underlying purpose of the respective provisions. Statutorily, § 112 requires that a patent specification enable a person of ordinary skill in the art to “make and use” the invention. Section 102, by contrast, contains no such requirement. This divergence reflects a difference in purpose: § 112 ensures that the patentee does not claim more than they have taught, thereby preventing overbroad monopolies. As the Supreme Court explained in Amgen, “[t]he more a party claims, the broader the monopoly it demands, the more it must enable.” But the Federal Circuit emphasized that the Supreme Court’s reasoning in Amgen was rooted in the patentee’s burden to support the full scope of a genus claim under § 112. That concern, the Court explained, does not apply in the § 102 context, where the question is not how much the prior art claims, but whether it teaches enough for a skilled artisan to practice at least one embodiment without undue [...]

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When “It’s Obvious” Just Isn’t Enough: Challenger’s Burden to Prove Obviousness

by | Mar 27, 2025 |

The US Court of Appeals for the Federal Circuit affirmed the Patent Trial & Appeal Board’s decision that a patent was not obvious because the petitioner failed to show sufficient support of obviousness based on prior art. AMP Plus, Inc. v. DMF, Inc., Case No. 23-1997 (Fed. Cir. Mar. 19, 2025) (Lourie, Bryson, Reyna, JJ.)

DMF owns a patent directed to a compact recessed lighting system designed for installation in a standard electrical junction box. In 2019, AMP, doing business as ELCO, petitioned for inter partes review of several claims of the patent on three grounds of unpatentability:

  • Anticipation by a prior reference
  • Obviousness based on a combination of two references
  • Further obviousness based on an additional source.

The Board found that one claim was anticipated but ruled that ELCO failed to prove unpatentability of the other claims, including the claim at issue on appeal. The claim at issue describes a system with wires connected to a driver and a first connector, coupled to a second connector that in turn is connected to the building’s electrical system. This specific connection was referred to as “Limitation M.” ELCO appealed. In that earlier appeal (2022), the Federal Circuit affirmed the Board’s ruling on all claims except the claim at issue and remanded the case back to the Board for further analysis.

On remand, the Board concluded that ELCO failed to demonstrate the unpatentability of the claim at issue because ELCO’s petition lacked a substantive analysis of Limitation M. The Board found ELCO’s argument that a prior art marine lighting system could be adapted for the claimed building use unsupported by evidence and ruled that the claim at issue was not obvious. Again, ELCO appealed.

ELCO raised two main arguments. First, it argued that the Board erred in not determining that the claim at issue was anticipated by a prior reference, as the Board had previously found another claim to be anticipated by the same reference. The Federal Circuit rejected this argument because ELCO had only challenged the claim at issue on the basis of obviousness in its original petition, not anticipation. Since the issue of anticipation was not raised in the petition, the Court determined that ELCO could not introduce this new ground of unpatentability on appeal.

Second, ELCO argued that its petition had sufficiently demonstrated the obviousness of Limitation M based on the prior references. The Federal Circuit disagreed, finding that ELCO’s petition did not adequately address the specific requirement for coupling the system to a building’s electrical infrastructure. The petition failed to discuss how the recessed lighting system would be installed in a building, and the references cited did not provide adequate support for the argument of obviousness for this particular limitation.

The Federal Circuit emphasized that it was not the Board’s responsibility to supplement the petitioner’s arguments or search for evidence to support an inadequately supported claim challenge. The Court reiterated that an obviousness analysis does not require the Board to fill gaps in the petitioner’s original [...]

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Construing Unambiguous Claim Language and Qualifying Challenged Expert as POSITA

by | Mar 20, 2025 |

Addressing the issues of claim construction and the requisite expert qualifications to testify on obviousness and anticipation, the US Court of Appeals for the Federal Circuit vacated a Patent Trial & Appeal Board decision invalidating half of the challenged patent’s claims and instructed the Board to clarify whether the patent owner’s expert was indeed qualified as a person of ordinary skill in the art (POSITA). Sierra Wireless, ULC v. Sisvel S.P.A., Case Nos. 23-1059; -1085; -1089; -1125 (Fed. Cir. Mar. 10, 2025) (Moore, CJ:  Schall, Taranto, JJ.)

Sisvel owns a patent directed to methods for retrieving data lost during wireless transmission. The prior art taught methods for flagging lost protocol data units (PDUs) so that the data transmitter could retry the transmission. Sisvel’s patent includes a timer that prescribes a period of time to elapse before alerting a transmitter of a missing PDU, allowing the transmission to be completed without notification. The patent has 10 claims, two of which are independent. The primary independent claim has four limitations, including one related to stopping the timer before a status report issues if the missing PDU is located and another related to issuing a status report upon the timer’s expiration. The limitations are linked by the word “and.”

Sierra Wireless initiated inter partes review (IPR), arguing that all 10 of the claims were both anticipated and obvious in light of the “Sachs” prior art patent. The Board found that half of the claims, including both independent claims, were anticipated and obvious. In finding that the other claims were not unpatentable, the Board relied on the testimony of Sisvel’s expert. Both parties appealed.

Sisvel raised two arguments in support of the claims the Board found unpatentable. First, Sisvel argued that the Board misconstrued the two above-noted limitations as mutually exclusive. Sisvel argued that the prior art had to teach both limitations to invalidate the claim. Second, Sisvel argued that the Board’s interpretation of Sachs’ teachings to include the first of the two limitations was unsupported by substantial evidence.

The Federal Circuit agreed. On the claim construction issue, the Court found that the two limitations in issue could not be mutually exclusive because the claim language linked them using the word “and.” To construe the limitations as mutually exclusive would be inconsistent with the unambiguous claim language. With regard to the prior art, the Court looked to Sachs Figure 5, which the Board relied upon in determining that the prior patent had taught the first limitation. Both the figure and the patent’s surrounding language made clear that the time referenced therein was dependent upon reordering of PDUs, not upon receiving missing ones. The Court thus vacated the Board’s invalidity determination as not supported by substantial evidence.

In its appeal, Sierra argued that the Board’s reliance on Sisvel’s expert’s testimony to find certain claims not unpatentable was an abuse of discretion. The Federal Circuit agreed, finding that the Board abused its discretion by not finding that the proposed expert qualified as a POSITA before relying [...]

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Inventor’s Motivation to Combine Does Not Control Obviousness

by | Mar 13, 2025 |

The US Court of Appeals for the Federal Circuit affirmed a district court decision rejecting claims of a patent application directed to a dosing regimen for a cancer treatment, finding the claims to be obvious where the motivation to use the claimed dosing was not the same as the inventor’s motivation. ImmunoGen, Inc. v. Coke Morgan Stewart, Case No. 23-1763 (Fed. Cir. Mar. 6, 2025) (Lourie, Dyk, Prost, JJ)

The claims at issue involved a dosing regimen for administering IMGN853, an already-patented antibody drug conjugate used for treating certain cancers, at a claimed dose of six milligrams (mg) per kilogram (kg) of adjusted ideal body weight (AIBW) of the patient.

ImmunoGen argued that it was undisputed that, at the time of the invention, a person of ordinary skill in the art would not have known that IMGN853 caused ocular toxicity in humans and that without a motivation to address the problem of ocular toxicity, the claimed dosing limitation could not have been obvious. Therefore, according to ImmunoGen, the district court erred in its motivation-to-combine analysis. The Federal Circuit disagreed, stating, “that the specific problem the inventors . . . purported to solve via the claimed dosing regimen was unknown does not necessarily mean that the dosing regimen itself was not obvious.” The Court also noted that because ocular toxicity was a well-known adverse event in the administration of drugs containing a payload included in IMGN853, “a person of ordinary skill in the art, despite not knowing of IMGN853’s ocular toxicity, would have nonetheless been motivated to monitor for those side effects when administering the drug to a human.”

ImmunoGen also argued that the district court erred in finding that a person of ordinary skill in the art would have been motivated to use AIBW dosing to eliminate ocular toxicity. The Federal Circuit again disagreed, reasoning that although AIBW dosing has not been used for drugs such as IMGN853, it would still have been within the range of knowledge of a person of ordinary skill in the art when addressing dosing-induced ocular toxicity. The Court explained that AIBW was well known, had been used for drugs both smaller and larger than IMGN853, and had proven effective in reducing ocular toxicity.

The Federal Circuit concluded that the district court did not clearly err in determining that a person of ordinary skill in the art would have been motivated to select the claimed dose of six mg/kg AIBW with a reasonable expectation of success. The claimed dose had already been described in the literature for patients at their ideal body weight, regardless of whether a doctor was aware of AIBW dosing specifically. The Court also noted that the district court was not required to find that a person of ordinary skill in the art would have had a reasonable expectation of eliminating ocular toxicity using the claimed dose, as “the obviousness inquiry is generally agnostic to the particular motivation of the inventor” and the claims made no reference to ocular toxicity.

Practice Note: [...]

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Validity Analysis for Product-by-Process Claim Focuses on Product

by | Mar 13, 2025 |

The US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board patentability finding, explaining that an anticipation analysis for a product-by-process claim focuses on the product and not the process. Restem, LLC v. Jadi Cell, LLC, Case No. 23-2054 (Fed. Cir. Mar. 4, 2025) (Moore, Schall, Taranto, JJ.)

Jadi Cell owns a patent directed to stem cells that have specific cell markers expressed. These stem cells are obtained from the subepithelial layer of mammalian umbilical cord tissue by first placing the layer in contact with a tissue culture growth substrate and then culturing the layer. The claims of the patent are product-by-process claims. Restem challenged certain claims of the patent in an inter partes review (IPR) petition as being anticipated by the Majore reference or obvious in view of Majore in combination with other references. The Board found that none of the challenged claims were shown to be unpatentable. Restem appealed.

The Board construed the claim term “placing a subepithelial layer of a mammalian umbilical cord tissue in direct contact with a growth substrate” to mean “to intentionally place umbilical cord tissue comprising the subepithelial layer so that it touches a growth substrate to permit cell culture.” The Board found that while the prior art references disclosed the two-step process in the claims, the references failed to disclose the claimed cells because the references did not necessarily produce cells with the claimed cell marker expression profile. Restem argued that the Board erred by construing the claims to require steps beyond the claimed two-step process. The Federal Circuit rejected that argument, finding that the Board had made underlying factual findings that supported its anticipation analysis in construing the “placing” step and therefore did not err.

In the underlying proceeding, the Board declined to construe “isolated cell” but construed “expresses/does not express” to mean that “the marker is confirmed present/absent relative to a control sample,” consistent with its interpretation of isolated cell to indicate a cell population. In construing this claim, the Board relied on extrinsic evidence to assess how a person of ordinary skill in the art would determine whether the cell markers were expressed. The Board found that both parties’ experts agreed that cell marker analysis was done at the cell population level at the time of invention. Restem argued that the Board erred in implicitly construing “isolated cell” contrary to the express definition in the challenged patent. However, the Federal Circuit upheld that implicit construction as supported by the intrinsic evidence because the specification consistently described the claimed invention as a cell population and the prosecution history indicated that the examiner only allowed the patentee to claim a cell population.

As for the Board’s finding that the Majore reference did not inherently or expressly anticipate the challenged claims, the Federal Circuit affirmed. The Board found that the cell marker expression profile distinguished the claimed cells from other stem cells and was therefore limiting, and that Majore did not expressly disclose the nonexpression limitations included [...]

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It’s Obvious: Erroneous Claim Construction Can Be Harmless

by | Feb 13, 2025 |

The US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board obviousness determination even though it found the Board had improperly construed a claim term, because the Court found the error harmless in the context of the prior art. HD Silicon Solutions LLC v. Microchip Technology Inc., Case No. 23-1397 (Fed. Cir. Feb. 6, 2025) (Lourie, Stoll, Cunningham, JJ.)

During a 2022 inter partes review (IPR), the Board determined that all but one of the 17 challenged patent claims were unpatentable as obvious in light of a prior patent (Trivedi) and other secondary prior art. The patent described methods of creating “a local interconnect layer in an integrated circuit” using two films. The independent claim recited a first film composed of titanium nitride and a second film as “comprising tungsten.” The Board construed “comprising tungsten” to include either elemental tungsten or tungsten-based compounds. The Board also found that the Trivedi patent disclosed films comprising either elemental tungsten or tungsten compounds. Thus, the Board held that all claims except one were obvious in light of Trivedi and that a person of ordinary skill in the art would have been motivated to combine Trivedi with other prior art. The patent owner appealed, arguing that the Board’s obviousness finding was dependent on the Board’s incorrect construction of the phrase “comprising tungsten.”

The Federal Circuit agreed that the Board’s claim construction was erroneous, because the term “comprising tungsten” required elemental tungsten. The Court explained that the claims explicitly used compound names when referring to compounds, such as “titanium nitride.” Thus, when the drafters wrote “comprising tungsten” without more, they clearly intended to exclude non-elemental tungsten options. The Court also noted that the patent specification used “tungsten” to reference only elemental tungsten and used the word “based” to encompass both elements and their compounds. For example, the patent discussed “chlorine-based” and “fluorine-based” components. Thus, the Court concluded that the claim drafters knew how to delineate when terms should include compounds, and that there was no such delineation in the term “comprising tungsten.”

The Board relied on a single sentence in the patent that stated: “the second film may comprise tungsten, for example,” to support its construction. The Federal Circuit rejected such a broad reading of this language, explaining that it only provided for impurities mixed among the elemental tungsten in the second film, rather than the film comprising a tungsten compound. The Board also cited a European Union (EU) patent in support of the construction that “comprising tungsten” explicitly included tungsten compounds. The Court stated that such extrinsic evidence was insufficient to overcome the asserted patent’s intrinsic teachings.

The Federal Circuit analyzed whether the Board’s obviousness holding could stand given its erroneous construction. The Court found that because the Board determined that Trivedi disclosed layers made of a tungsten compound and elemental tungsten, the patent claims were obvious when the disputed term was properly construed to be limited to elemental tungsten. Thus, the Board’s error was harmless.



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Complex or Not Written Description Is Evaluated Against Claims

by | Jan 23, 2025 |

The US Court of Appeals for the Federal Circuit reversed a district court’s ruling of invalidity for lack of written description, finding that the district court erred in its analysis of written description because patents must be evaluated based on the claims themselves, not on their construction. In re Entresto, Case No. 23-2218 (Fed. Cir. Jan. 10, 2025) (Lourie, Prost, Reyna, JJ.)

Novartis owns an approved new drug application (NDA) for a combination therapy of valsartan and sacubitril that Novartis markets under the brand name Entresto®. The term “combination therapy” is used to describe pharmaceuticals where two or more active pharmaceutical ingredients are combined in a single method of treatment. Entresto® is protected by several patents, including the patent at issue. Several generic pharmaceutical manufacturers, including MSN, filed abbreviated new drug applications (ANDAs) seeking to market generic versions of Entresto® prior to the expiration of Novartis’ patent. Novartis sued for infringement.

A unique property of Entresto® is the specific form taken by the active pharmaceutical ingredients, valsartan and sacubitril. The valsartan and sacubitril in Entresto® are present in what is known as a “complex,” meaning the two drugs are bonded together by weak, noncovalent bonds. At issue before the district court was the construction of the claim term “wherein said [valsartan and sacubitril] are administered in combination.” The inquiry focused on whether “in combination” required the valsartan and sacubitril to be chemically separated molecules (not in the form of a complex). The district court adopted Novartis’ proposal to give the term its plain and ordinary meaning because the intrinsic record was silent as to whether the molecules must be separate and not complexed. The complexed form of valsartan and sacubitril was not developed until four years after the priority date of the patent.

After the district court declined to adopt MSN’s “complexed” claim construction, MSN stipulated to infringement. The case proceeded to a bench trial on the issue of validity. The district court found the patent not invalid for obviousness, lack of enablement, and indefiniteness. However, the district court ruled that because the patent did not disclose the complexed form of valsartan and sacubitril, it was invalid for lack of written description. Novartis appealed.

Novartis argued that a complex of valsartan and sacubitril was an after-arising invention that need not have been enabled or described. The Federal Circuit agreed, finding that because the patent did not claim the complexed form of valsartan and sacubitril, those complexes need not have been described. The Court cited its “long-recognized” rule that “the invention is, for purposes of the written description inquiry, whatever is now claimed.” All that was required to meet the written description requirement was a disclosure sufficient to show that the inventors possessed a pharmaceutical composition comprising valsartan and sacubitril administered in combination. The Federal Circuit found that by considering what the claims were “construed to cover,” the district court improperly conflated the distinct issues of patentability and infringement. The Federal Circuit reversed the district court’s finding of invalidity for lack [...]

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Bit Swap: Motivation to Modify Prior Art Needn’t Be Inventor’s Motivation

by | Jan 16, 2025 |

Addressing the issue of obviousness, the US Court of Appeals for the Federal Circuit reversed a Patent Trial & Appeal Board decision, finding that the challenged patent claims were obvious because a person of ordinary skill in the art (POSITA) would have been motivated to switch two specific information bits in a 20-bit codeword to improve performance. Honeywell Int’l Inc. v. 3G Licensing, S.A., Case Nos. 23-1354; -1384; -1407 (Fed. Cir. Jan. 2, 2025) (Dyk, Chen, JJ.) (Stoll, J., dissenting).

3G Licensing owns a patent concerning a coding method for transmitting a channel quality indicator (CQI) in mobile communication systems. The CQI, a five-bit binary integer (0 to 30) is sent from user equipment, such as a cell phone, to a base station to indicate cellular connection quality. Base stations adjust data rates using adaptive modulation and coding, assigning higher rates to strong signals and lower rates to weaker ones. CQI accuracy is critical for maximizing data transmission efficiency and ensuring recovery of the original message despite transmission errors.

The challenged claims of the 3G patent relate to a CQI code designed to maximize protection of the most significant bit (MSB) to reduce the impact of transmission errors. The prior art disclosed a method and a basis sequence table that provided additional protection to the MSB, minimizing root-mean-square error. However, the claimed invention differed in that it required swapping the last two bits of the basis sequence table. The Board found that a skilled artisan would not have been motivated to make this modification to enhance MSB protection, nor would a skilled artisan have deemed it desirable. Honeywell appealed.

The Federal Circuit reversed, finding the claims obvious for four primary reasons. First, the Court determined that the Board incorrectly concluded that a POSITA would not have been motivated to swap the last two bits to improve MSB protection. The Court emphasized that the motivation to modify prior art does not need to align with the inventor’s motivation. As a result, the Board’s reasoning that minimizing root-mean-square error was not the patent’s primary purpose should not have been a primary consideration.

Second, the Federal Circuit found that prior art explicitly taught the importance of protecting the MSB through redundancy. A skilled artisan would have understood that swapping the two bits, as claimed, would add redundancy and enhance protection. Honeywell’s expert testimony further supported the conclusion that the prior art would have provided the requisite motivation to arrive at the claimed invention, and 3G’s expert did not dispute that the swap increased MSB protection.

Third, the Federal Circuit concluded that the Board improperly conflated obviousness with anticipation by requiring that the prior art disclose swapping the two bits. Anticipation requires the prior art to specifically disclose the claimed modification, but obviousness does not. The Court found that the Board erroneously treated the two standards as interchangeable.

Finally, the Federal Circuit found that the Board wrongly required that the claimed basis sequence table represent the preferred or most optimal combination. As the Court [...]

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Motivation MIA? Federal Circuit Sends IPR Back to the Drawing Board

by | Jan 9, 2025 |

The US Court of Appeals for the Federal Circuit vacated and remanded a Patent Trial & Appeal Board decision, finding that the Board erred by failing to explain its holding and reasoning regarding a motivation to combine prior art references. Palo Alto Networks, Inc. v. Centripetal Networks, LLC, Case No. 23-1636 (Fed. Cir. Dec. 16, 2024) (Stoll, Dyk, Stark, JJ.)

Centripetal Networks owns a patent directed to correlating packets in communications networks, introducing an innovative system designed to enhance network security. The patent focuses on packets (small data segments that collectively form larger communications) and their correlation across network boundaries.

Palo Alto Networks challenged the patent’s validity in an inter partes review (IPR) and argued its obviousness based on three prior art references. The first reference described a system using hashing techniques to identify packets traversing network address translation boundaries and teaching how to correlate packets across such boundaries to identify hosts transmitting or receiving them. The second reference detailed methods for detecting unauthorized traffic directed to unused IP addresses, notifying administrators of potential threats, and enabling automated responses, such as blocking or filtering malicious traffic. The reference taught notifying administrators how to manage packets involved in malicious activity after they crossed a network boundary.

Palo Alto argued that combining the packet correlation techniques of the first reference with the notification mechanisms of the second addressed a key claim limitation of the challenged patent. Palo Alto contended that transmitting an indication of a malicious host, as taught by the second reference, naturally followed from the correlation system described in the first. However, the Board found that Palo Alto failed to provide sufficient evidence or argument to show that a person of ordinary skill in the art (POSITA) would recognize the claimed responsiveness between the first reference’s packet correlation and the second reference’s notification mechanisms. Palo Alto appealed.

The Federal Circuit vacated and remanded the Board’s decision, finding that the Board erred by failing to clearly articulate its rationale regarding the motivation to combine the prior art references and whether their combination satisfied the critical limitation of the challenged patent claim. The Court emphasized that the proper inquiry in an obviousness analysis is not whether each reference individually discloses all claim elements but whether their combination would have rendered the invention obvious to a POSITA.

Palo Alto maintained that the Board did not dispute the existence of a motivation to combine and improperly searched for a “bridge” solely within the two references. Centripetal countered that Palo Alto had not established a motivation or provided evidence of a necessary connection – or “bridge” – between the prior art and the claimed invention.

The Federal Circuit determined that the Board’s decision lacked a definitive finding on whether a POSITA would have been motivated to combine the first reference’s correlation techniques with the second reference’s notification step. The Court noted that Palo Alto presented logical and evidentiary support as to why such a combination would make sense, arguing that without a notification step, the [...]

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