US Patent 8,722,037: Scope, Claims, Expiration and Patent Landscape for Nexplanon

US Patent 8,722,037 covers a radiopaque subdermal contraceptive implant using crystalline etonogestrel, also known as 3-ketodesogestrel, in an ethylene-vinyl acetate matrix. The strongest claims are directed to the commercial Nexplanon architecture: a 40 mm by 2 mm coaxial rod containing 68 mg of etonogestrel, barium sulfate distributed within the polymer phase, and a non-medicated EVA outer skin.

The patent is primarily a formulation-and-device patent, not a patent on etonogestrel itself. Its commercial relevance is tied to the combination of drug loading, EVA composition, radiopaque-agent placement, implant dimensions and applicator configuration. Based on the apparent PCT filing chronology, the US patent term was expected to end in January 2025, subject to any patent-term adjustment or terminal disclaimer reflected in the USPTO record.

What does US Patent 8,722,037 protect?

The patent protects a subdermal drug-delivery rod containing:

Crystalline desogestrel or 3-ketodesogestrel.
A thermoplastic polymer, principally ethylene-vinyl acetate.
Approximately 4% to 30% by weight of a radiopaque material.
Radiopaque material substantially encapsulated in the polymer rather than incorporated into the crystalline steroid.
A non-medicated thermoplastic polymer skin surrounding the medicated core.

The patent corresponds technically to the radiopaque version of the etonogestrel implant marketed as Nexplanon. The radiopaque component permits visualization by X-ray or other imaging methods, distinguishing Nexplanon from the earlier non-radiopaque Implanon configuration.

The patent does not broadly claim every etonogestrel implant. Infringement generally requires the accused product to satisfy the claimed material, composition, structural and dimensional limitations.

What are the independent claims in US 8,722,037?

The patent contains four principal independent claim groups.

Claim	Independent subject matter	Main limitations
1	Drug-delivery device	Crystalline desogestrel or 3-ketodesogestrel; thermoplastic polymer at a weight percentage no greater than the steroid; 4% to 30% radiopaque material; radiopaque material substantially encapsulated in polymer; non-medicated polymer skin
8	Coaxial implant	EVA core with approximately 28% vinyl acetate; EVA skin with approximately 14% vinyl acetate; radiopaque material in the core
16	Specific implant	40 mm length, 2 mm diameter, 68 mg crystalline 3-ketodesogestrel, 8% to 15% barium sulfate, specified EVA core and skin
19	Broader device	Crystalline desogestrel or 3-ketodesogestrel; less than 50% thermoplastic polymer; 4% to 30% radiopaque material substantially encapsulated in polymer; non-medicated polymer skin

Claims 1 and 19 are the broadest composition claims. Claim 8 is more structurally specific. Claim 16 is the closest claim to the commercial Nexplanon product.

How broad is claim 1?

Claim 1 has five central limitations.

First, the active ingredient must be crystalline desogestrel or crystalline 3-ketodesogestrel. Etonogestrel is the relevant commercial compound. A formulation using a different progestin would fall outside the literal active-ingredient limitation.

Second, the core must contain a thermoplastic polymer. EVA is a preferred and separately claimed polymer, but claim 1 is not limited to EVA.

Third, the polymer percentage must be equal to or less than the percentage of desogestrel or 3-ketodesogestrel. This relative-weight limitation is important. A formulation containing more polymer than steroid would not literally satisfy this part of claim 1.

Fourth, the core must contain approximately 4% to 30% radiopaque material. Claims 2 and 3 narrow the range to approximately 6% to 20% and 8% to 15%, respectively.

Fifth, substantially all radiopaque material must be encapsulated in the thermoplastic polymer and not in the crystalline steroid. This is the claim's principal manufacturing and microstructural limitation.

A competing implant could seek design-around protection by changing the active form, radiopaque-agent location, radiopaque concentration, polymer-to-drug ratio or outer-layer construction. Whether a modified product remains within the claims would depend on the actual microstructure and on the application of equivalents.

How does claim 19 expand the patent scope?

Claim 19 replaces claim 1's polymer-to-steroid relationship with a less-than-50%-by-weight polymer limitation.

This creates a potentially broader claim because the core polymer need not be less than or equal to the steroid weight. It must only be below 50% by weight. The claim continues to require:

Crystalline desogestrel or 3-ketodesogestrel.
4% to 30% radiopaque material.
Substantial encapsulation of the radiopaque material in the polymer.
A non-medicated thermoplastic polymer skin.

Claims 20 through 24 narrow claim 19 by specifying radiopaque concentration, barium sulfate, implant form and EVA polymer.

The practical scope depends on the total composition basis used for the percentage calculations. A party assessing infringement would need validated batch composition data, polymer identity, active form, radiopaque distribution and manufacturing records.

What formulations are protected by the patent?

The most commercially important formulation is the claim 16 configuration:

Feature	Claimed specification
Active ingredient	68 mg crystalline 3-ketodesogestrel
Core polymer	EVA with approximately 28% vinyl acetate
Radiopaque material	Barium sulfate
Radiopaque concentration	Approximately 8% to 15% by weight
Outer skin	Non-medicated EVA with approximately 14% vinyl acetate
Device geometry	40 mm length and 2 mm diameter
Device structure	Coaxial rod
Rod ends	Open ends under dependent claim 17
Applicator	ABS body and plunger, stainless-steel needle and polypropylene shield under claim 18

The claims distinguish the drug-containing core from the non-medicated outer skin. A product using a medicated outer coating, a non-thermoplastic barrier layer or a materially different polymer system could avoid one or more limitations.

The claims also focus on the radiopaque material's location. Simply adding barium sulfate to a finished implant is not necessarily enough. The patent requires that substantially all of it be encapsulated in the thermoplastic polymer and not in the crystalline steroid.

What is the relationship between the patent and Nexplanon?

Nexplanon is a single-rod subdermal contraceptive implant containing 68 mg of etonogestrel. The FDA label identifies the rod as a flexible, non-biodegradable implant with an EVA-based structure and barium sulfate for radiopacity. The implant is supplied with a dedicated applicator for subdermal insertion (FDA, 2024).

The patent's claim 16 closely tracks these commercial characteristics. The relationship is strongest for:

68 mg etonogestrel loading.
40 mm by 2 mm rod dimensions.
EVA core and EVA skin.
Barium sulfate radiopacity.
Coaxial rod construction.
Dedicated applicator.

The patent should not be treated as proof that every technical feature of Nexplanon is protected exclusively by US 8,722,037. Commercial products can be covered by multiple patent families, regulatory exclusivity, manufacturing know-how and device patents.

When did US Patent 8,722,037 expire?

The patent appears to derive from a European priority filing dated January 16, 2004, with an international filing in January 2005. On that chronology, the ordinary 20-year US patent term would have ended in January 2025, before any applicable patent-term adjustment.

Milestone	Date or period
Earliest claimed priority	January 16, 2004
Approximate international filing period	January 2005
US grant	May 13, 2014
Expected ordinary US term endpoint	January 2025
Commercial significance after term	Patent-based exclusion materially reduced or ended, subject to any surviving related patents

The relevant term calculation is based on the applicable US filing chronology, not simply the grant date. Patent-term adjustment, terminal disclaimers and continuity records can affect the precise enforceable endpoint. The FDA Orange Book patent listing should be used for the regulatory patent date associated with the NDA (FDA, Orange Book).

What is the Orange Book status of US 8,722,037?

The patent is associated with the Nexplanon/etonogestrel implant regulatory product and is relevant to the Orange Book patent-listing analysis for the product.

An Orange Book listing does not establish validity or infringement. It places the patent in the Hatch-Waxman framework and can require an ANDA applicant to submit a Paragraph IV certification if the applicant seeks approval before the listed patent's expiration. The listing also does not mean that every patent claim covers every possible etonogestrel implant.

For a generic or follow-on implant, the critical regulatory question would be whether the reference-listed drug is submitted through an ANDA, a 505(b)(2) application or another pathway. A product with materially different delivery characteristics, applicator design or clinical performance may face a more complex regulatory route than a conventional oral generic.

What Paragraph IV challenges affect the patent?

The supplied record does not establish a specific Paragraph IV notice letter, ANDA sponsor, district-court complaint or settlement involving US 8,722,037.

A Paragraph IV challenge would likely focus on one or more of the following positions:

The prior art disclosed etonogestrel or desogestrel implants with EVA matrices.
Radiopaque additives such as barium sulfate were known in implantable devices.
The claimed concentration range was an obvious optimization.
Encapsulation of barium sulfate in the polymer was an inherent result of extrusion or coextrusion.
The patent lacks written-description support for the full ranges.
Terms such as "about" and "substantially all" are indefinite or lack objective boundaries.

The patent holder would likely respond that the claims require a specific combination of active crystallinity, polymer-to-drug ratio, radiopaque loading, radiopaque location and non-medicated skin. The combination of these limitations may provide a stronger obviousness defense than any individual feature considered separately.

How strong is the patent estate?

The patent is strongest against a product that copies the commercial Nexplanon architecture. Its strength is lower against a product that changes the radiopaque-agent location or uses a materially different implant platform.

Risk factor	Assessment
Product-specific coverage	High for the claimed 68 mg, 40 mm by 2 mm radiopaque rod
Broad active-ingredient coverage	Moderate; limited to desogestrel or 3-ketodesogestrel
Polymer coverage	Moderate; independent claims broadly recite thermoplastic polymer, with EVA dependent claims
Radiopaque-agent limitation	Strong structural limitation but creates a design-around route
Formulation overlap	High for EVA/barium sulfate/etonogestrel products
Manufacturing evidence required	High, because radiopaque encapsulation may not be visible from public labeling
Post-expiration value	Limited as an exclusion right; potentially useful as prior-art and freedom-to-operate history

The patent's commercial value was highest before the projected January 2025 expiry. After expiry, remaining risk would come from related patents, regulatory exclusivity, trade secrets, process patents and patent families covering applicators or alternative implant structures.

What generic entry risks exist?

Conventional generic entry

A conventional ANDA sponsor would need to address both the active drug and the implant delivery system. The product would need to match or bridge the reference product's:

Drug release profile.
Implant dimensions.
Drug content.
Biocompatibility.
Applicator performance.
Sterility and packaging.
Subdermal insertion characteristics.

The patent's composition and structure claims could create infringement risk for a copy product, particularly if the sponsor uses the same EVA grades, barium sulfate loading and 68 mg etonogestrel design.

505(b)(2) entry

A 505(b)(2) applicant could pursue a modified implant or delivery system while relying partly on FDA findings for etonogestrel. The route would not automatically eliminate patent risk. A materially different formulation may avoid literal infringement but require additional clinical or pharmacokinetic support.

Biosimilar risk

There is no conventional biosimilar pathway for Nexplanon. Etonogestrel is a chemically synthesized small molecule, not a biologic. Competitive entry would involve an ANDA, 505(b)(2) application or another small-molecule drug-device pathway, not a biosimilar application under the Public Health Service Act.

Which companies are challenging or competing with Nexplanon?

Nexplanon is supplied by Organon, following Merck's separation of its women's-health business. The main competitive alternatives are not direct copies of the same radiopaque implant architecture.

Product or company category	Competitive position
Organon Nexplanon	Single-rod etonogestrel implant
Bayer Jadelle	Two-rod levonorgestrel implant; different active ingredient and architecture
Bayer Mirena/Kyleena/Skyla	Intrauterine levonorgestrel systems; different route and device
Copper IUD manufacturers	Non-hormonal intrauterine contraception
Potential generic developers	Could target etonogestrel implant through ANDA or 505(b)(2) pathways

Jadelle and levonorgestrel intrauterine systems generally would not infringe the asserted claims because they do not use the claimed desogestrel or 3-ketodesogestrel active ingredient.

What manufacturing and IP barriers matter?

The highest technical barrier is controlling the distribution of barium sulfate during coextrusion. The claims require the radiopaque material to be substantially encapsulated in the polymer phase and not in the crystalline steroid. This may require specialized compounding, extrusion and quality-control methods.

Other barriers include:

Maintaining crystalline etonogestrel during processing.
Achieving consistent drug loading along a narrow rod.
Controlling EVA vinyl acetate content.
Producing a uniform non-medicated skin.
Preventing diffusion defects and dose dumping.
Validating radiopacity over the product shelf life.
Integrating the implant with a sterile applicator.
Demonstrating reliable insertion and removal.

These manufacturing parameters may remain commercially important after patent expiry because they can be protected through process patents, confidential know-how and regulatory manufacturing controls.

Does US 8,722,037 cover the applicator?

Claims 14, 15 and 18 cover kits containing the implant and an applicator. Claim 18 is the most specific and recites:

An acrylonitrile-butadiene-styrene polymer applicator.
A body.
A plunger.
A stainless-steel needle.
A polypropylene shield.

The applicator claims are narrower than the implant claims. An alternative applicator material or configuration may avoid literal infringement, although other patents or regulatory requirements could still affect commercialization.

Key Takeaways

US 8,722,037 is directed to a radiopaque etonogestrel implant, not to etonogestrel as a molecule.
The commercial core is a 68 mg crystalline etonogestrel rod using EVA and barium sulfate.
The principal technical distinction is that the radiopaque material is substantially encapsulated in the polymer rather than in the crystalline steroid.
Claims 1 and 19 provide the broadest device coverage; claim 16 most closely matches the commercial Nexplanon configuration.
The patent's expected ordinary US term ended in January 2025, subject to the USPTO's final term records.
An ANDA or 505(b)(2) entrant would face formulation, device, applicator and regulatory-comparability issues.
Biosimilar entry is not the relevant pathway because etonogestrel is a small molecule.
A design-around could change the active form, polymer system, radiopaque-agent location, loading ratio, device geometry or applicator.
Post-expiration exposure depends principally on related patents, process rights, trade secrets and FDA requirements.

FAQs

Is US Patent 8,722,037 a patent on Implanon or Nexplanon?

It is primarily associated with the radiopaque Nexplanon-type implant. Implanon was the earlier non-radiopaque etonogestrel implant. The patent's barium sulfate and imaging-related limitations are more closely aligned with Nexplanon.

Does using barium sulfate automatically infringe US 8,722,037?

No. Infringement would require all limitations of an asserted claim. The product would also need to satisfy the claimed active ingredient, polymer, concentration range, skin structure and encapsulation relationship.

Can a competitor avoid the patent by using levonorgestrel?

For the claims provided, generally yes as to literal active-ingredient scope. The claims require desogestrel or 3-ketodesogestrel. A levonorgestrel implant would need to be assessed against other patents, but it would not ordinarily satisfy this active-ingredient limitation.

Is the 68 mg etonogestrel amount independently protected?

The 68 mg limitation appears in claim 13 and claim 16. A lower or higher amount may avoid those claims but could remain within broader claims 1 or 19 if the other composition and structural limitations are met.

What is the most important freedom-to-operate test for a competing implant?

The key test is whether the competitor uses crystalline etonogestrel in an EVA or other thermoplastic core with 4% to 30% radiopaque material substantially encapsulated in the polymer, covered by a non-medicated polymer skin. Manufacturing cross-sections and formulation records are likely more important than the product's public label alone.

References

U.S. Patent No. 8,722,037. (2014). Radiopaque contraceptive implant. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2024). Nexplanon (etonogestrel implant) prescribing information. FDA.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.
U.S. Food and Drug Administration. (2024). Code of Federal Regulations, Title 21, section 314.53: Submission of patent information. FDA.
Patent Term Adjustment Act, 35 U.S.C. § 154. (2024). United States Code.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Organon	NEXPLANON	etonogestrel	IMPLANT;IMPLANTATION	021529-002	May 13, 2011		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial	Y				⤷ 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

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
	04101151	Mar 19, 2004

PCT Information
PCT Filed	March 14, 2005	PCT Application Number:	PCT/EP2005/051150
PCT Publication Date:	September 29, 2005	PCT Publication Number:	WO2005/089814

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	048106	⤷ Start Trial
Austria	E399569	⤷ Start Trial
Australia	2005224054	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,722,037

Which drugs does patent 8,722,037 protect, and when does it expire?

Summary for Patent: 8,722,037