Nyxoah SA v. Inspire Medical Systems Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Nyxoah SA (Belgium) and Nyxoah, Inc. (Delaware)
  • Defendant: Inspire Medical Systems, Inc. (Delaware)
  • Plaintiff’s Counsel: Duane Morris LLP
• Case Identification: 1:25-cv-01147, D. Del., 09/15/2025
• Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant is a Delaware corporation that maintains a registered agent in the district.
• Core Dispute: Plaintiff alleges that Defendant’s implantable nerve stimulation systems for treating sleep apnea, the Inspire IV and Inspire V, infringe three U.S. patents related to low-current neural modulation technology.
• Technical Context: The technology involves implantable medical devices that treat obstructive sleep apnea by delivering electrical stimulation to the hypoglossal nerve, which controls tongue muscles to prevent airway collapse during sleep.
• Key Procedural History: The complaint alleges that Defendant was aware of Plaintiff’s patent family, including the patents-in-suit, at least as early as July 2, 2020, based on Defendant’s disclosure of related Nyxoah patents to the U.S. Patent and Trademark Office during the prosecution of its own patent application. This allegation forms the basis for Plaintiff's claim of willful infringement.

Case Timeline

Date	Event
2011-09-30	Earliest Priority Date for ’183, ’215, and ’216 Patents
2014-04-15	U.S. Patent No. 8,700,183 Issues
2016-08-16	U.S. Patent No. 9,415,215 Issues
2016-08-16	U.S. Patent No. 9,415,216 Issues
2020-07-02	Alleged earliest date of Defendant's awareness of patent family
2025-09-15	Complaint Filed

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

U.S. Patent No. 8,700,183 - "Devices and Methods for Low Current Neural Modulation"

• Patent Identification: U.S. Patent No. 8,700,183, issued April 15, 2014 (Compl. ¶8).

The Invention Explained

• Problem Addressed: The patent addresses obstructive sleep apnea (OSA), a condition characterized by the collapse of pharyngeal muscles during sleep, which obstructs the airway. The patent notes that in OSA patients, the genioglossus muscle (a primary tongue muscle) exhibits decreased neuromuscular activity, preventing it from contracting sufficiently to keep the airway open (’183 Patent, col. 1:41-61).
• The Patented Solution: The invention is an implantable device designed to be placed near the hypoglossal nerve, which innervates the genioglossus muscle. The device’s electrodes deliver a low-current electrical signal (less than about 1.6 milliamps) to generate an electric field that modulates the nerve without direct physical contact. This non-contacting modulation is intended to cause the tongue muscle to contract, thereby opening the airway (’183 Patent, Abstract; col. 2:52-65).
• Technical Importance: The low-current, non-contact approach is presented as an advantage, as it may reduce power consumption and remain effective even if the device migrates slightly within the body over time, a potential issue for implants requiring direct nerve contact (Compl. ¶12; ’183 Patent, col. 17:16-30).

Key Claims at a Glance

• The complaint asserts independent Claim 1 (Compl. ¶26).
• Essential elements of Claim 1 include:
  • A sleep disordered breathing treatment device comprising an implantable circuit and at least one pair of implantable electrodes.
  • The circuit and electrodes are configured for implantation proximal to a genioglossus muscle in the vicinity of a hypoglossal nerve.
  • The circuit is configured to deliver an electrical signal having a current of less than about 1.6 milliamps.
  • The electrodes are configured to emit an electric field that causes modulation of the hypoglossal nerve from a location "spaced apart from the hypoglossal nerve and external to a blood vessel."

U.S. Patent No. 9,415,215 - "Methods for Treatment of Sleep Apnea"

• Patent Identification: U.S. Patent No. 9,415,215, issued August 16, 2016 (Compl. ¶13).

The Invention Explained

• Problem Addressed: The patent pertains to methods for treating sleep apnea via hypoglossal nerve stimulation, with an apparent focus on improving the precision of the therapy.
• The Patented Solution: The invention is a method for treating sleep apnea that involves implanting a device on the underside of a subject's chin. The method comprises receiving a signal, applying it to electrodes to generate an electric field, and causing nerve modulation that is specifically "confined to a medial branch of the hypoglossal nerve" and "initiated from a single modulation site" (Compl. ¶17). This suggests a technique for selective nerve activation.
• Technical Importance: By targeting only a specific nerve branch (the medial branch) responsible for tongue protrusion, the method may offer more efficient airway opening while minimizing stimulation of other nerve branches that control different tongue movements, potentially reducing side effects and improving therapeutic outcomes (Compl. ¶17).

Key Claims at a Glance

• The complaint asserts independent Claim 1 (Compl. ¶38).
• Essential elements of Claim 1 include:
  • Receiving a modulation signal at an implant unit implanted on an underside of a subject's chin.
  • Applying the signal to at least one pair of electrodes to generate an electric field.
  • Causing modulation of a hypoglossal nerve where the modulation is "confined to a medial branch" of the nerve.
  • The modulation is "initiated from a single modulation site along the medial branch."

U.S. Patent No. 9,415,216 - "Devices for Treatment of Sleep Apnea"

• Patent Identification: U.S. Patent No. 9,415,216, issued August 16, 2016 (Compl. ¶18).
• Technology Synopsis: The ’216 Patent claims a system for treating sleep apnea, comprising a flexible carrier with electrodes and a neurostimulation device. The system is configured for placement near the genioglossus muscle to cause airway dilation "solely through stimulation of a portion of the subject’s hypoglossal nerve through application of an electric field to a single section of a medial branch" of that nerve (Compl. ¶22). This patent appears to claim the physical system that would be used to perform the method claimed in the ’215 patent.
• Asserted Claims: The complaint asserts independent Claim 1 (Compl. ¶50).
• Accused Features: The Inspire IV and Inspire V systems are alleged to be the infringing systems (Compl. ¶¶25, 51).

III. The Accused Instrumentality

Product Identification

• The Inspire IV and Inspire V systems, identified collectively as the "Accused Products" (Compl. ¶25). When in use, these products are alleged to perform the "Accused Methods" (Compl. ¶37).

Functionality and Market Context

• The complaint describes the Accused Products as systems that "treat patients with a sleep disorder through synchronous nerve stimulation therapy methods" (Compl. ¶25). The complaint does not provide further technical detail on the operation of the Accused Products, instead referring to claim charts in exhibits that were not attached to the publicly filed document (Compl. ¶¶26, 38, 50). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

U.S. Patent No. 8,700,183 Infringement Allegations

The complaint alleges that the Accused Products directly infringe at least Claim 1 of the ’183 Patent (Compl. ¶27). It references a claim chart in Exhibit 4, which was not provided with the complaint, to show how the products meet each limitation (Compl. ¶26). Without this exhibit, the specific factual basis for the infringement allegation is not detailed in the pleading.

U.S. Patent No. 9,415,215 Infringement Allegations

The complaint alleges that the Accused Methods performed by the Accused Products directly infringe at least Claim 1 of the ’215 Patent (Compl. ¶39). It references a claim chart in Exhibit 5, which was not provided with the complaint, for specific details mapping the method steps to the claim elements (Compl. ¶38).

Identified Points of Contention

• Scope Questions (’183 Patent): A central question may be the interpretation of modulating the nerve from "a location spaced apart." The dispute may focus on whether this language requires a complete absence of physical contact between the electrode and the nerve or nerve sheath, or if it can be read on devices that are designed for contact but may functionally operate with a gap (e.g., through a membrane or fluid).
• Technical Questions (’215 Patent): A significant factual dispute may arise over whether the nerve modulation caused by the Accused Methods is truly "confined to a medial branch." This raises the evidentiary question of how Plaintiff will prove that the electric field generated by the accused system does not cause therapeutically relevant stimulation of adjacent nerve branches.

V. Key Claim Terms for Construction

"a location spaced apart from the hypoglossal nerve" (’183 Patent, Claim 1)

• Context and Importance: This term is critical to the non-contacting infringement theory of the ’183 Patent. The viability of the infringement claim may depend on whether this term is construed to preclude devices designed to make physical contact with the nerve (e.g., via a cuff electrode).
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification’s emphasis on the benefits of contactless modulation, such as accommodating device migration over time, could support an interpretation that distinguishes the invention from prior art requiring precise and permanent contact, rather than mandating a specific minimum distance (’183 Patent, col. 17:16-30).
  • Evidence for a Narrower Interpretation: The patent’s figures and description show embodiments where electrodes are placed on a muscle surface, with the nerve embedded deep within that muscle, suggesting a clear physical separation by intervening tissue is contemplated (’183 Patent, Fig. 1; col. 15:30-34).

"confined to a medial branch" (’215 Patent, Claim 1)

• Context and Importance: This term defines the specificity of the claimed treatment method. The infringement analysis for the ’215 Patent will likely hinge on whether the stimulation from the Accused Methods meets this restrictive requirement.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The complaint does not provide the specification of the ’215 patent. However, a party might argue that "confined to" should be interpreted functionally, meaning that the therapeutically effective modulation occurs on the medial branch, even if some incidental or sub-therapeutic electrical field leakage affects other areas.
  • Evidence for a Narrower Interpretation: The plain language of the term suggests an absolute boundary. A party could argue that if any measurable or functional modulation occurs on any part of the hypoglossal nerve other than the medial branch, the limitation is not met.

VI. Other Allegations

Indirect Infringement

• The complaint alleges induced infringement of all three patents, asserting that Defendant provides instructions, training materials, and demonstrations that actively encourage and aid physicians and patients to implant and use the Accused Products in an infringing manner (Compl. ¶¶28-29, 40-41, 52-53). Contributory infringement is also alleged for the ’215 patent, stating the Accused Products are especially adapted for the infringing use and are not staple articles of commerce (Compl. ¶44).

Willful Infringement

• Willfulness is alleged based on both post-suit knowledge from the filing of the complaint and, more significantly, on alleged pre-suit knowledge or willful blindness (Compl. ¶¶33, 46, 57). The pre-suit allegation is based on Defendant’s citation of related Nyxoah patents to the USPTO during the prosecution of its own patent application, allegedly occurring as early as July 2, 2020 (Compl. ¶¶31, 43, 55).

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

• A core issue will be one of technical operation versus claim scope: For the ’183 patent, can the requirement for modulation from a "spaced apart" location be met by the accused Inspire systems, whose design may contemplate direct nerve contact? For the ’215 and ’216 patents, does the electric field generated by the accused systems in practice achieve the high degree of anatomical precision—being "confined to" and acting "solely through" the medial nerve branch—recited in the claims?
• A second central question will be one of intent: Did Defendant’s citation of Plaintiff’s related patents during its own patent prosecution establish pre-suit knowledge or willful blindness regarding the patents-in-suit, and if so, does this rise to the level of egregious conduct required for a finding of willful infringement and potential enhanced damages?