Inspire Medical Systems Inc v. Nyxoah Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Inspire Medical Systems, Inc. (Delaware)
  • Defendant: Nyxoah, Inc. (Delaware) and Nyxoah SA (Belgium)
  • Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP; Latham & Watkins LLP
• Case Identification: 1:25-cv-00667, D. Del., 05/30/2025
• Venue Allegations: Venue is alleged to be proper because Defendant Nyxoah, Inc. is incorporated in Delaware, and Defendant Nyxoah SA is a foreign corporation subject to personal jurisdiction in the district.
• Core Dispute: Plaintiff alleges that Defendants’ Genio system for treating obstructive sleep apnea infringes three U.S. patents related to asynchronous neurostimulation therapy.
• Technical Context: The technology involves implantable medical devices that electrically stimulate the hypoglossal nerve to prevent airway obstruction during sleep, offering an alternative to traditional CPAP machines.
• Key Procedural History: The complaint notes that the asserted ’526 and ’424 patents are continuations of the asserted ’709 patent family. Plaintiff also alleges it sent Defendants a notice letter identifying the asserted patents and the alleged infringement prior to filing suit.

Case Timeline

Date	Event
2015-03-19	Priority Date for ’709, ’526, and ’424 Patents
2020-07-01	Nyxoah began selling Genio device in Europe
2021-01-26	U.S. Patent No. 10,898,709 Issues
2022-01-01	Nyxoah began its "DREAM Study" clinical trial for the U.S. market
2023-03-01	Nyxoah filed first module for FDA premarket approval of Genio
2023-11-07	U.S. Patent No. 11,806,526 Issues
2023-12-26	U.S. Patent No. 11,850,424 Issues
2024-06-01	Nyxoah submitted final module for FDA premarket approval of Genio
2025-03-26	Nyxoah announced receipt of an "approvable letter" from the FDA
2025-05-30	Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,898,709 - Stimulation for treating sleep disordered breathing, Issued January 26, 2021

The Invention Explained

• Problem Addressed: The patent addresses obstructive sleep apnea ("OSA"), where relaxation of the tongue and throat muscles obstructs the airway during sleep (’709 Patent, col. 1:20-24). While nerve stimulation can alleviate this, prior art systems often required complex sensors to synchronize the stimulation with the patient’s breathing cycle, specifically the inspiratory phase (’709 Patent, col. 3:3-10).
• The Patented Solution: The invention proposes a neurostimulation therapy that is asynchronous, meaning it does not rely on actively sensing the patient's breathing to time the stimulation (’709 Patent, col. 3:25-36, FIG. 17A). The system applies a repeating cycle of a stimulation period followed by a non-stimulation period. The key insight is that the overall duration of this stimulation cycle is intentionally designed not to match the duration of the patient’s natural respiratory cycle. This causes the stimulation periods to gradually "drift" across the patient's breathing phases over time, ensuring that a significant majority of inspiratory phases receive therapeutic stimulation without needing a sensor to detect them (’709 Patent, col. 5:1-14).
• Technical Importance: This approach may simplify the design and implantation of the neurostimulation device by eliminating the need for dedicated respiratory sensors and the associated processing for synchronization, which can be a point of failure or complexity (’709 Patent, col. 6:35-44).

Key Claims at a Glance

• The complaint asserts infringement of at least independent Claim 1 (Compl. ¶86).
• Essential elements of Claim 1 include:
  • A non-cardiac stimulation element to stimulate an upper-airway-patency-related nerve.
  • The stimulation is delivered according to a first stimulation therapy protocol that is not synchronized relative to actively-sensed respiratory information.
  • The protocol comprises a series of repeating stimulation cycles, each including a stimulation period and a non-stimulation period.
  • Each stimulation period includes continuous stimulation and has a minimum duration equal to or greater than an inspiratory reference of a reference respiratory cycle.
  • The stimulation period is followed by a non-stimulation period with a duration less than that of the stimulation period.
• The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 11,806,526 - Stimulation for treating sleep disordered breathing, Issued November 7, 2023

The Invention Explained

• Problem Addressed: As a continuation of the ’709 Patent, this patent addresses the same technical problem of providing effective, simplified neurostimulation therapy for OSA without requiring complex synchronization hardware (’526 Patent, col. 1:20-24).
• The Patented Solution: The solution is also an asynchronous stimulation protocol. It is described as a "stimulation means" that applies a therapy protocol with alternating stimulation and non-stimulation periods where the timing is "asynchronous relative to patient breathing" (’526 Patent, col. 3:25-36, Abstract). The protocol's timing is based on a "reference respiratory-related parameter" rather than real-time sensing, with the duration of the stimulation period being greater than the non-stimulation period (’526 Patent, Claim 1).
• Technical Importance: The technical contribution remains the potential simplification of OSA neurostimulators by removing the need for direct, real-time synchronization with a patient's breathing cycle (’526 Patent, col. 6:35-44).

Key Claims at a Glance

• The complaint asserts infringement of at least independent Claim 1 (Compl. ¶98).
• Essential elements of Claim 1 include:
  • A device with a non-cardiac stimulation means for stimulating an upper airway patency-related nerve.
  • The stimulation means comprises an implantable electrode and/or an implantable pulse generator.
  • The stimulation is applied according to a protocol with alternating stimulation and non-stimulation periods.
  • The timing of the stimulation periods is asynchronous relative to patient breathing.
  • The duration of each stimulation period is greater than the duration of each non-stimulation period.
  • The duration of each stimulation period is based on a reference respiratory-related parameter.
• The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 11,850,424 - Stimulation for treating sleep disordered breathing, Issued December 26, 2023

• Technology Synopsis: This patent is a continuation in the same family as the ’709 and ’526 patents and is directed to similar technology (Compl. ¶82). It describes a method for treating OSA by applying asynchronous electrical stimulation to the hypoglossal nerve, using a protocol of alternating stimulation and non-stimulation periods whose timing is independent of the patient’s real-time breathing cycle to maintain airway patency (’424 Patent, Abstract; col. 1:20-24).
• Asserted Claims: At least Claim 1 (Compl. ¶110).
• Accused Features: The complaint alleges that the Nyxoah Genio system's use of asynchronous hypoglossal neurostimulation infringes this patent (Compl. ¶33, ¶35).

III. The Accused Instrumentality

Product Identification

• The accused instrumentality is the Nyxoah "Genio" sleep apnea treatment system (Compl. ¶4).

Functionality and Market Context

• The Genio system is designed to treat OSA using "asynchronous hypoglossal neurostimulation" (Compl. ¶33). The complaint describes the system as comprising an implantable stimulator and a detachable, external "activation chip" (Compl. ¶34). The activation chip, which contains a chipset and a rechargeable battery, adheres to the patient's chin and provides power and control signals to the implant (Compl. ¶34). The implant, in turn, has paddle electrodes that deliver bilateral electrical stimulation to the hypoglossal nerve to cause forward movement of the tongue and maintain an open airway (Compl. ¶34). A schematic in the complaint illustrates the system's components, including the implantable stimulator, activation chip, disposable patch, and charging unit (Compl. ¶34, p. 9). The complaint alleges that Genio delivers stimulation at a "predetermined programmed rate, without sensing the user's actual breathing activity" (Compl. ¶35). Nyxoah is alleged to be preparing for an imminent U.S. launch following imminent FDA approval, positioning itself as a "smart follower" to Inspire (Compl. ¶4, ¶37).

IV. Analysis of Infringement Allegations

The complaint references, but does not include, claim chart exhibits detailing its infringement theories. The following summarizes the narrative infringement allegations for each patent.

• ’709 Patent Infringement Allegations
  The complaint alleges that Nyxoah’s Genio system directly and indirectly infringes at least Claim 1 of the ’709 Patent (Compl. ¶86, ¶89-90). The infringement theory is based on the allegation that the Genio system is a "non-cardiac stimulation element" that stimulates the hypoglossal nerve, which is an "upper-airway-patency-related nerve" (Compl. ¶34). The complaint alleges that Genio’s protocol is "not synchronized" with breathing because it delivers stimulation at a "predetermined programmed rate, without sensing the user’s actual breathing activity" (Compl. ¶35). The complaint does not, however, provide specific factual allegations mapping the Genio system's operational timing (e.g., the duration of its stimulation and non-stimulation periods) to the specific requirements of Claim 1 concerning a "reference respiratory cycle" and an "inspiratory reference."

• ’526 Patent Infringement Allegations
  The complaint asserts that the Genio system infringes at least Claim 1 of the ’526 Patent (Compl. ¶98, ¶101-102). The "non-cardiac stimulation means" limitation is allegedly met by the Genio system’s combination of an implantable stimulator and an external activation chip that functions as a pulse generator (Compl. ¶34). The core of the infringement allegation is that the Genio system's protocol is "asynchronous relative to patient breathing" (Compl. ¶35). The complaint does not provide sufficient detail for analysis of how the Genio system's stimulation and non-stimulation period durations allegedly meet the specific limitations of Claim 1, such as the requirement that the stimulation period duration is based on a "reference respiratory-related parameter."

• Identified Points of Contention:

  • Scope Questions: The dispute may center on the definition of "asynchronous" and "not synchronized." A central question for the court could be whether these terms simply mean the absence of a real-time breathing sensor, or if they require the more specific, mathematically-defined relationship between the stimulation cycle and a "reference respiratory cycle" that is described in the patent specifications.
  • Technical Questions: A key evidentiary question will be what proof demonstrates that the Genio system’s pre-programmed stimulation protocol meets the quantitative requirements of the claims. For example, what evidence shows that Genio’s stimulation period has a duration "equal to or greater than an inspiratory reference" as required by Claim 1 of the ’709 Patent? The complaint also alleges Nyxoah has imported Genio components into the U.S. on numerous occasions, citing an FDA import database screenshot, which may be a point of factual dispute regarding the nature and purpose of those importations (Compl. ¶62).

V. Key Claim Terms for Construction

• The Term: "asynchronous relative to patient breathing" (’526 Patent) / "not synchronized relative to actively-sensed respiratory information" (’709 Patent)
• Context and Importance: This concept is the central feature of the asserted patents and the primary basis for the infringement allegations. The outcome of the case may depend on whether the Genio system's "predetermined programmed rate" of stimulation falls within the scope of this term. Practitioners may focus on this term because it distinguishes the patented invention from prior art that required sensors for synchronization.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specifications repeatedly contrast the invention with systems that "trigger stimulation by synchronizing the stimulation relative to characteristics of the sensed respiratory waveform" (’709 Patent, col. 3:5-8). Language describing the invention as operating "without any sensing elements at all" or with "minimal use of sensing elements" could support a broad construction that covers any system that does not rely on real-time breathing sensors (’709 Patent, col. 6:32-35).
  • Evidence for a Narrower Interpretation: The specifications also provide detailed descriptions of how the asynchronous protocol is carefully designed to work. They explain that the "overall duration of the stimulation cycle... intentionally does not match the duration (R) of the reference respiratory cycle," which ensures the stimulation period drifts across the patient's breathing phases to provide therapeutic benefit (’709 Patent, col. 5:2-9). A defendant may argue that "asynchronous" requires not just the absence of a sensor, but the presence of this specific, intentionally mismatched timing relationship, which may not be practiced by the accused device.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Nyxoah provides "significant support and documentation, such as manuals, guides, webpages, and videos that instruct users to use Genio in an infringing manner" (Compl. ¶91, ¶103, ¶115).
• Willful Infringement: The complaint alleges willfulness based on both pre- and post-suit knowledge. It alleges Nyxoah was aware of Inspire’s patent portfolio due to its business model as a "smart follower" that "has studied Inspire and its activities intently" (Compl. ¶67). The complaint also alleges that Inspire sent Nyxoah an "Inspire Notice Letter," providing actual notice of the asserted patents and the alleged infringement prior to the lawsuit (Compl. ¶69, ¶93).

VII. Analyst’s Conclusion: Key Questions for the Case

The resolution of this dispute may turn on the following central questions:

• A core issue will be one of definitional scope: How will the court construe the term "asynchronous" / "not synchronized"? Will it be interpreted broadly to mean any neurostimulation that is not actively tied to a real-time breathing sensor, or will it be construed more narrowly to require the specific, intentionally mismatched timing protocols relative to a "reference respiratory cycle" as detailed in the patent specifications?
• A key evidentiary question will be one of technical proof: Beyond the general characterization of the Genio system as "asynchronous," what evidence will be presented to demonstrate that its operational parameters—specifically the durations of its stimulation and non-stimulation periods—meet the detailed quantitative limitations recited in the asserted independent claims? The complaint provides a high-level theory but does not currently offer specific facts on this point.
• A third question will relate to infringing acts: Given that the Genio system is not yet fully commercialized in the U.S., the case may involve detailed factual inquiries into whether Nyxoah's pre-launch activities, such as importation for clinical trials, testing, and marketing preparations, constitute acts of infringement under 35 U.S.C. § 271 (Compl. ¶61-62).