US Patent 9,585,681: Scope, Claim Construction, Patent Landscape, and Generic-Entry Risk

US Patent No. 9,585,681 covers a method of placing a bioabsorbable, radially expandable, pronged device in a paranasal sinus cavity. The independent claim is directed to the implantation procedure and structural configuration of the device, not to a drug product alone. The claim requires a plurality of filaments joined at their proximal ends, with free distal ends that expand radially outwardly and remain in the sinus after withdrawal of the delivery device. The patent is most relevant to bioabsorbable sinus implants, steroid-eluting sinus devices, postoperative sinus-care systems, and competing delivery platforms.

The strongest infringement risk arises where a product combines all of the following: a sinus-placed implant; a delivery sheath or catheter; a self-expanding or otherwise expandable radial structure; a single proximal junction; free distal filament ends; retention within the sinus after delivery-device withdrawal; and, potentially, mometasone furoate release.

What does US Patent 9,585,681 cover?

The patent covers a method of delivering an expandable paranasal sinus device rather than merely the device as an article of manufacture.

Claim 1 requires each of these elements:

Claim element	Scope and practical meaning
Advancing a device into a paranasal sinus cavity	The method must place the device in a sinus cavity, not only in the nasal passage or ostium
Bioabsorbable expandable device	The device must be capable of expansion and absorption or degradation in the body
Sized and shaped for the sinus cavity	The device is designed to fit within, and at least partly conform to, the sinus anatomy
Pronged structure	The device has a branching or radial configuration rather than a conventional cylindrical stent alone
Plurality of filaments	The structure uses multiple elongate filament members
Radial outward expansion	The filaments expand away from a central or proximal region
Proximal ends joined together	The filaments share a proximal junction or joined proximal region
Distal ends free	The distal ends are not joined to one another or to a distal ring
Delivery-device withdrawal	The delivery instrument is removed after placement
Device remains in the sinus	The implant must remain in the cavity after the delivery device is completely withdrawn

This combination creates a structural and procedural limitation set. A device may avoid literal infringement if it lacks the claimed proximal-only junction, has joined distal ends, does not remain in the sinus after withdrawal, or is not bioabsorbable.

How should independent claim 1 be construed?

Claim 1 is a combination claim. Every limitation must be present for literal infringement. The claim does not cover every bioabsorbable sinus implant or every radially expandable sinus device.

The "pronged structure" limitation

"Pronged structure" is supported by the more specific requirement that multiple filaments expand radially outwardly from a joined proximal region. The claim does not define a fixed number of prongs. A product with three, four, or more filaments could fall within the numerical scope if the remaining limitations are satisfied.

The absence of a specified filament count leaves the claim broad as to the number of prongs. It does not, however, eliminate the requirement that the device contain multiple filaments.

The proximal-only connection

The phrase "only the proximal ends of each filament join together" is one of the claim's most important limitations. It distinguishes the claimed structure from:

A closed distal loop;
A cage with proximal and distal rings;
A woven or braided mesh;
Filaments joined at both ends;
A continuous tubular scaffold;
A stent with interconnected struts throughout its length.

A product may have secondary contact between filaments during deployment without necessarily having joined distal ends. Physical contact and structural joining are different issues, but the product's drawings, specifications, manufacturing process, and deployed geometry would be material to claim construction.

Free distal ends

Each filament must have a free distal end. A distal end that is welded, bonded, sutured, molded, or otherwise structurally connected to another filament creates a potential noninfringement position.

The claim does not require the distal ends to be pointed, separated by a specified distance, or independently movable. It requires that they remain free rather than joined.

Conformability

The device must be "at least partly conformable" to the sinus cavity. The claim therefore does not require complete anatomical conformity. A device that contacts or adapts to only part of the sinus cavity may satisfy the limitation if its design and deployment provide the required conformity.

Retention after delivery

The device must remain in the paranasal sinus cavity after the delivery device has been completely withdrawn. Temporary expansion during catheter delivery is insufficient. The implant must retain its position independently of the delivery tool.

This limitation separates the claimed method from balloon dilation, temporary dilators, removable stents, and devices that remain attached to a deployment catheter.

What do dependent claims 2 through 12 add?

The dependent claims narrow claim 1 through material, drug, visualization, anchoring, dimensional, and delivery-system limitations.

Claim	Added limitation	Commercial significance
2	Device configured to biodegrade	Requires a degradable implant, not merely a removable expandable device
3	One or more biodegradable polymers	Targets polymeric resorbable implants
4	Device releases one or more active agents	Covers drug-eluting or biologically active implants
5	Active agent includes mometasone furoate	Narrows the drug-elivery concept to a corticosteroid commonly used in sinus treatment
6	One or more radiopaque markers	Covers fluoroscopic or radiographic localization
7	Indirect visualization	Covers imaging-based visualization, such as fluoroscopy or radiography
8	Direct visualization during advancement	Covers endoscopic delivery under direct observation
9	Self-expanding device	Removes the need for an external expansion step after deployment
10	Anchoring elements on each filament	Targets barbs, hooks, projections, or similar retention structures
11	Filament length of about 2 cm to about 5 cm	Adds a dimensional limitation relevant to sinus anatomy and device sizing
12	Handle, sheath, and distal loading portion	Defines a catheter-like delivery system

Claim 5 is particularly relevant to a drug-device combination product. It does not claim mometasone furoate as a compound, a pharmaceutical composition, or a nasal spray. It claims a method using the claimed expandable sinus device when the active agent includes mometasone furoate.

What formulations are protected by US Patent 9,585,681?

The patent claims an active-agent-releasing device, but the supplied claims do not specify:

Mometasone concentration;
Total drug load;
Release duration;
Polymer composition;
Drug-polymer ratio;
Particle size;
Coating thickness;
Elution kinetics;
Manufacturing process;
Sterilization method;
Specific salt, ester, or crystalline form.

Claim 4 is broad as to the active agent, while claim 5 is narrower because it identifies mometasone furoate. The claims therefore reach a broad category of drug-eluting sinus implants but do not independently establish protection for every mometasone formulation.

A competing product could present a lower literal-infringement risk if it uses a non-eluting implant, releases a different active agent, or uses a formulation that is not incorporated into the claimed expandable device. That analysis would still depend on whether the product satisfies claim 1.

Does the patent cover Propel, Sinuva, Latera, or other sinus products?

The claims are potentially relevant to products that combine a bioabsorbable sinus implant with radial prongs or filaments. They do not automatically cover every product sold for sinus disease.

Product category	Likely relevance
Balloon sinuplasty catheters	Generally outside the claim if no retained bioabsorbable pronged implant remains after catheter withdrawal
Removable sinus stents	Generally outside the claim if the device is not bioabsorbable
Bioabsorbable steroid-eluting implants	Higher risk if the implant has the claimed proximal-junction/free-distal-filament architecture
Cylindrical drug-eluting sinus implants	Potentially outside claim 1 if they lack the pronged structure
Nasal valve implants	Generally outside the claim if not delivered into a paranasal sinus cavity
Endoscopic sinus spacers	Fact-dependent; risk turns on structure, retention, biodegradation, and drug release
Polymeric sinus scaffolds	Potentially relevant if they have the claimed radial filament configuration

Products such as Intersect ENT's Propel and Sinuva systems occupy the broader bioabsorbable, steroid-eluting sinus-implant market, but product names alone do not establish infringement. The relevant comparison is the actual device architecture, delivery method, labeling, regulatory documentation, and patent claims.

Latera-type implants are generally directed to nasal valve support rather than placement in a paranasal sinus cavity. That anatomical distinction can materially reduce relevance to claim 1.

What is the Orange Book status of US Patent 9,585,681?

US Patent 9,585,681 is not an Orange Book patent merely because claim 5 identifies mometasone furoate. The Orange Book concerns approved drug products and patents submitted by the relevant new-drug application holder under the Hatch-Waxman framework. A sinus implant that combines a device with an active ingredient is not automatically treated as an Orange Book-listed drug product.

The patent appears to be a device and method patent, not a patent for a standalone mometasone drug product. Orange Book listing, if any, would depend on the approved product, application type, submission by the NDA holder, and FDA listing practices. The patent number itself does not establish Orange Book status.

Are Paragraph IV challenges or generic-entry notices relevant?

Paragraph IV litigation is generally directed to an approved drug application and a patent listed in the Orange Book. US Patent 9,585,681 is structurally different from a conventional drug patent because its claims require a sinus implant and a delivery method.

The likely regulatory paths are:

A standalone device submission, potentially under a 510(k), De Novo, or PMA pathway;
A combination-product pathway involving FDA's Office of Combination Products;
A drug-device application where the primary mode of action and regulatory lead center determine the pathway;
A follow-on device submission that does not use the same drug or implant architecture.

A competitor could challenge the patent through an inter partes review, post-grant review if available within the statutory window, district-court invalidity defenses, or a declaratory-judgment action. A conventional ANDA Paragraph IV certification would not be the default route for a device-method patent.

How strong is the patent estate based on the supplied claims?

The claim set has meaningful design-around exposure because claim 1 is highly specific. Its strength comes from the combination of anatomical placement, biodegradability, radial filament expansion, proximal-only joining, free distal ends, and retained placement.

Strengths

The claim reaches the method of implantation, not only the physical device.
The claim does not require a particular polymer, allowing coverage of multiple biodegradable materials.
The claim does not require a particular active agent in the independent claim.
Claim 5 specifically addresses mometasone furoate.
The self-expanding and anchoring limitations capture commercially practical retention mechanisms.
The delivery-system claim covers a conventional handle-and-sheath platform.

Weaknesses and design-around routes

Use a non-bioabsorbable implant.
Use a completely closed or interconnected distal architecture.
Use a cylindrical or sheet-like implant without prongs.
Keep the implant attached to the delivery device during the claimed step.
Place the device in the nasal passage or ostium rather than a paranasal sinus cavity.
Use a removable device that does not biodegrade.
Use a device that does not release an active agent if avoiding claims 4 and 5.
Replace the proximal-only junction with a structure in which the filaments are not joined together.
Use a balloon-expanded or mechanically deployed structure instead of a self-expanding pronged implant.
Alter filament length outside the 2 cm to 5 cm range to avoid claim 11, while recognizing that claim 11 is only a dependent claim.

The most important design-around target is the proximal-only, free-distal-end geometry. Altering drug choice alone does not avoid claim 1.

What patent landscape surrounds this technology?

The relevant landscape has several overlapping patent groups:

Bioabsorbable sinus implants

These patents generally address implants that maintain sinus patency or deliver therapy while degrading in situ. Claim scope often focuses on polymer selection, degradation rate, implant geometry, and placement location.

Steroid-eluting sinus devices

These patents cover incorporation or release of corticosteroids, including mometasone, from a sinus implant. The principal issues are drug loading, polymer matrices, release profiles, and the treatment period after sinus surgery.

Delivery catheters and deployment systems

Separate patent families cover handles, sheaths, loading chambers, deployment mechanisms, endoscopic visualization, and controlled release of the implant from the distal portion of the catheter.

Anchoring and retention structures

Other patent families may claim barbs, hooks, fins, expanding arms, friction elements, or anatomical engagement structures. These rights can create blocking positions even when a product avoids the exact filament structure in US 9,585,681.

Manufacturing and sterilization

Manufacturing patents may cover molding, filament formation, polymer blending, drug incorporation, marker placement, crimping, loading, and sterilization. These patents can remain commercially important after a core device patent expires.

Which companies are relevant competitors?

The commercial landscape has included companies developing sinus implants, balloon systems, corticosteroid-eluting devices, and endoscopic delivery platforms. Relevant entities include:

Intersect ENT, associated with Propel and Sinuva products;
Stryker, including its sinus and ENT device portfolio;
Johnson & Johnson subsidiaries and Acclarent-branded sinus technologies;
Medtronic, including balloon and sinus-surgery systems;
Entellus Medical, whose ENT portfolio was acquired by Stryker;
Smaller specialty-device companies developing resorbable sinus spacers and drug-eluting implants.

The existence of a competing product does not show that it practices the claims. A product-level freedom-to-operate review must compare the deployed implant, not only the product's intended use.

What litigation and settlement issues matter?

For this type of patent, the relevant disputes would likely involve:

Claim construction of "pronged structure";
Meaning of "only the proximal ends ... join together";
Whether the distal ends are legally "free";
Whether the implant remains in the sinus after full withdrawal;
Whether the implant is bioabsorbable or merely biodegradable under particular conditions;
Whether a product's drug release satisfies the active-agent limitation;
Whether the accused method is actually performed according to labeling or clinical use;
Written-description and enablement challenges for broad device and active-agent language;
Obviousness based on sinus spacers, expandable implants, polymer scaffolds, and drug-eluting devices.

A settlement could provide a license, a covenant not to sue, field-of-use restrictions, geographic restrictions, or an agreed product redesign. No settlement terms should be inferred from the patent claims alone.

When does US Patent 9,585,681 lose exclusivity?

Patent expiration must be calculated from the complete priority and continuity chain, the earliest effective nonprovisional filing date, any patent-term adjustment, and any terminal disclaimer. The issued patent number does not itself establish the expiration date.

The patent's expiration is separate from:

FDA regulatory exclusivity;
Orphan-drug exclusivity;
New chemical entity exclusivity;
Device market access;
Orange Book listing;
Patent-term extension for an approved drug product.

Because the supplied claims are for a sinus device-delivery method, the commercial exclusivity period may depend more on patent-family continuations and related formulation or delivery patents than on this patent alone. A freedom-to-operate review should therefore include continuation patents, divisionals, reissues, terminal disclaimers, and later patents assigned to the same commercial owner.

What generic and follow-on launch risks exist?

A follow-on entrant faces three principal risks.

First, a device that copies the claimed pronged architecture may face direct infringement exposure even if it uses a different drug or polymer. Second, a mometasone-eluting implant may face additional formulation and combination-product patents. Third, regulatory clearance does not provide freedom to operate. FDA authorization and patent rights are separate questions.

Launch strategies include:

A noninfringing redesign using a closed distal structure;
A non-bioabsorbable or removable implant;
A different anatomical placement;
A non-drug-eluting device;
A different retention mechanism;
A license or acquisition of relevant patent rights;
An invalidity challenge based on prior art or claim-defect theories.

Key Takeaways

US Patent 9,585,681 claims a delivery method for a retained, bioabsorbable, expandable sinus device.
The central structural limitation is a plurality of radially expanding filaments joined only at their proximal ends, with free distal ends.
Claim 1 does not cover every sinus implant, steroid-eluting device, or balloon catheter.
Claim 5 specifically targets use of mometasone furoate but does not claim mometasone as a standalone drug.
The patent is more relevant to drug-device combination products than to ordinary generic mometasone products.
Paragraph IV certification is not the default challenge mechanism for this device-method patent.
The strongest design-around strategy is to change the filament-junction and distal-end architecture.
Exact patent expiration requires review of the full continuity, patent-term-adjustment, and terminal-disclaimer records.
Orange Book status cannot be inferred from the patent's reference to mometasone furoate.
Continuation, formulation, delivery-system, anchoring, manufacturing, and polymer patents may create additional blocking rights.

Frequently Asked Questions

Does US Patent 9,585,681 claim a sinus implant itself?

No. The supplied independent claim is a method claim. It requires advancing and deploying the device, withdrawing the delivery device, and leaving the expandable device in the sinus cavity.

Can a product infringe if it uses fluticasone instead of mometasone?

Potentially. Claim 1 does not require mometasone or any active agent. Using fluticasone could avoid claim 5 but would not avoid claim 1 if the complete structural and procedural limitations are met.

Can a closed distal loop avoid the patent?

It may avoid literal infringement of the free-distal-end limitation and the requirement that only proximal filament ends join. The full product architecture and claim construction would control.

Is a sinus implant patent automatically listed in the Orange Book?

No. Orange Book listing depends on the approved drug application and statutory listing requirements. A device-method patent is not automatically an Orange Book patent.

Does FDA clearance eliminate infringement risk?

No. FDA authorization addresses regulatory marketing requirements. It does not grant a patent license or resolve infringement, validity, or freedom-to-operate issues.

References

United States Patent and Trademark Office. (2017). U.S. Patent No. 9,585,681.
United States Patent and Trademark Office. (n.d.). Patent Center. https://patentcenter.uspto.gov/
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files
U.S. Food and Drug Administration. (n.d.). Office of Combination Products. https://www.fda.gov/about-fda/office-commissioner/office-clinical-policy-and-programs/office-combination-products
U.S. Code, 35 U.S.C. §§ 154, 271, 311-319.
U.S. Code, 21 U.S.C. §§ 355, 355(j).

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Intersect Ent Inc	SINUVA	mometasone furoate	IMPLANT;IMPLANTATION	209310-001	Dec 8, 2017		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial				TREATMENT OF NASAL POLYPS IN PATIENTS >=18 YEARS OF AGE WHO HAVE HAD ETHMOID SINUS SURGERY USING A CORTICOSTEROID-ELUTING (MOMETASONE FUROATE) IMPLANT	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2006231506	⤷ Start Trial
Canada	2603081	⤷ Start Trial
China	101189016	⤷ Start Trial
European Patent Office	1871383	⤷ Start Trial
European Patent Office	2298317	⤷ Start Trial
European Patent Office	2298318	⤷ Start Trial
European Patent Office	2298319	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,585,681

Which drugs does patent 9,585,681 protect, and when does it expire?

Summary for Patent: 9,585,681