Details for Patent: 11,166,960

Which drugs does patent 11,166,960 protect, and when does it expire?

Patent 11,166,960 protects OXTELLAR XR and is included in one NDA.

This patent has fourteen patent family members in ten countries.

Summary for Patent: 11,166,960

Title:	Modified release preparations containing oxcarbazepine and derivatives thereof
Abstract:	Controlled-release preparations of oxcarbazepine and derivatives thereof for once-a-day administration are disclosed. The inventive compositions comprise solubility- and/or release enhancing agents to provide tailored drug release profiles, preferably sigmoidal release profiles. Methods of treatment comprising the inventive compositions are also disclosed.
Inventor(s):	Padmanabh P. Bhatt, Argaw Kidane, Kevin Edwards
Assignee:	Supernus Pharmaceuticals Inc
Application Number:	US17/238,796
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 11,166,960
Patent Claim Types: see list of patent claims	Use; Formulation; Compound;

United States Patent 11,166,960: Oxcarbazepine Controlled-Release Formulation Scope, Claims, and Patent Landscape

U.S. Patent 11,166,960 protects a once-daily controlled-release oxcarbazepine formulation built around a homogeneous polymer matrix, a solubility-enhancing excipient, and an enteric release-promoting polymer. The independent claim is formulation-focused and does not require a particular tablet shape, manufacturing process, dissolution profile, or named commercial product. The principal infringement risk is therefore directed to extended-release oxcarbazepine products that combine a matrix polymer, a solubility enhancer, and a pH-dependent enteric polymer.

The patent is associated with Supernus Pharmaceuticals’ Oxtellar XR product, an extended-release oxcarbazepine tablet approved by the FDA for adjunctive therapy in partial-onset seizures in adults and children six years of age and older.[1][2]

What does U.S. Patent 11,166,960 claim?

Claim 1 is the controlling claim. It requires all four elements below:

Claim element	Required scope
Active ingredient	Oxcarbazepine
Dosage architecture	Controlled-release formulation with a homogeneous matrix
Matrix-forming polymer	Cellulosic polymer, alginate, gum, cross-linked polyacrylic acid, carrageenan, polyvinyl pyrrolidone, polyethylene oxide, or polyvinyl alcohol
Solubility enhancer	At least one agent that enhances oxcarbazepine solubility
Release-promoting agent	At least one agent comprising an enteric polymer

A product must satisfy each limitation of claim 1, either literally or under a potential doctrine-of-equivalents theory, to fall within the independent claim.

The claim does not limit the formulation to a single matrix polymer. It presents a broad Markush group. A formulation using hydroxypropyl methylcellulose, polyethylene oxide, polyvinylpyrrolidone, an alginate, or another listed polymer can satisfy the matrix-polymer limitation if the remaining elements are present.

How broad is the independent claim?

Claim 1 is broad in excipient selection but narrower in formulation architecture.

The claim does not cover every extended-release oxcarbazepine product. It requires:

1. A homogeneous matrix rather than merely any controlled-release dosage form.
2. A matrix-forming polymer from the specified list.
3. A separate or identifiable solubility-enhancing agent.
4. An enteric polymer that functions as a release-promoting agent.

A conventional osmotic-pump tablet, multiparticulate system, coated pellet, liposomal formulation, or diffusion-controlled dosage form may avoid claim 1 if it does not contain the required homogeneous polymer matrix. The presence of an enteric coating alone would not necessarily establish infringement because the claim requires the enteric polymer to be a release-promoting agent within the claimed formulation architecture.

The claim also does not expressly require:

• A 600-mg dose;
• Once-daily dosing;
• A specific pharmacokinetic profile;
• A particular Cmax or Cmin value;
• A named enteric polymer;
• A particular dissolution percentage at a specified time;
• A specific tablet coating;
• A particular manufacturing process.

Those limitations appear in dependent claims or in the specification, not in claim 1.

What do claims 2 through 6 add?

Claim	Added limitation	Commercial significance
2	Minimizes fluctuations between Cmin and Cmax of the monohydroxy derivative of oxcarbazepine	Links the formulation to a pharmacokinetic performance objective
3	Contains 600 mg of oxcarbazepine	Directly targets the 600-mg commercial strength
4	Enteric polymer has pH-dependent solubility	Narrows the release-promoting polymer to an acid-resistant or pH-responsive class
5	Can be administered once daily	Covers the commercial dosing frequency
6	Solubility enhancer is a surfactant, complexing agent, cyclodextrin, pH modifier, or hydration-promoting agent	Narrows the excipient category while preserving several alternatives

Claim 3 is commercially important because Oxtellar XR is marketed in 150-mg, 300-mg, and 600-mg extended-release tablets.[2] A competing 600-mg product may face a direct claim if it also uses the claimed matrix and excipient structure.

Claim 5 is narrower than claim 1 because it requires suitability for once-daily administration. A twice-daily product could still infringe claim 1 if it otherwise meets the formulation limitations.

Claim 2 is potentially difficult to enforce without pharmacokinetic evidence. The phrase "effective in minimizing fluctuations" may require comparison with a reference formulation or an objectively defined fluctuation metric. It is less suited to an early composition-only infringement case than claims 1, 3, 4, and 6.

What formulations are protected by U.S. Patent 11,166,960?

The patent is most relevant to formulations containing the following combination:

• Oxcarbazepine;
• A hydrophilic or swellable matrix polymer;
• A solubility-enhancing excipient;
• An enteric or pH-dependent polymer that modifies drug release.

Potentially relevant matrix polymers include:

• Hydroxypropyl methylcellulose and other cellulose derivatives;
• Polyethylene oxide;
• Polyvinylpyrrolidone;
• Polyvinyl alcohol;
• Alginate-based polymers;
• Gums;
• Cross-linked polyacrylic acid;
• Carrageenan.

Potential solubility-enhancing agents include surfactants, cyclodextrins, complexing agents, pH modifiers, and hydration-promoting materials. The claim language does not require that the solubility enhancer be chemically bonded to oxcarbazepine. It may be an excipient incorporated into the dosage form.

The most important claim-construction issue is whether the formulation has a "homogeneous matrix." A product using a core matrix with a separate enteric coating may present a factual dispute over whether the claimed enteric polymer is part of the homogeneous matrix or otherwise functions as the claimed release-promoting agent. The patent specification and prosecution history would be important in determining the scope of that term.

When does Patent 11,166,960 lose exclusivity?

The patent’s expected base statutory term is tied to the earliest effective nonprovisional priority date in its family, rather than to the 2021 grant date. The patent family traces to an oxcarbazepine controlled-release formulation program filed in 2007. On that basis, the nominal 20-year term is expected to reach December 2027, subject to any patent-term adjustment, terminal disclaimer, patent-term extension, or later correction shown in the official USPTO records.[3]

Event	Date or status
Earliest family priority	December 2007 family filing
Patent grant	November 9, 2021
Expected base expiration	December 2027, subject to official term calculation
FDA product	Oxtellar XR, NDA 201004
Regulatory pathway	505(b)(2)/NDA product, not a biologic
Generic pathway	ANDA with paragraph IV certification

The 2021 grant date does not provide a new 20-year term. A patent issuing late in its family life generally expires 20 years from the applicable earliest nonprovisional filing date, with adjustments under the Patent Term Adjustment statute.

What is the Orange Book status of Patent 11,166,960?

Oxtellar XR is an FDA-approved small-molecule drug listed in the Orange Book. It is not eligible for biosimilar competition under the Public Health Service Act because oxcarbazepine is a chemically synthesized small molecule.[1][4]

The relevant competitive pathway is an abbreviated new drug application. An ANDA applicant may submit:

• Paragraph I, if no patent information is listed;
• Paragraph II, if the patent has expired;
• Paragraph III, if the applicant will wait until expiration; or
• Paragraph IV, if the applicant alleges that the listed patent is invalid, unenforceable, or not infringed.

A valid paragraph IV notice can trigger a 30-month stay of FDA approval if the patent owner or NDA holder files an infringement action within the statutory period.[5]

Patent 11,166,960 is formulation-oriented. Its Orange Book significance depends on whether it is listed against the approved Oxtellar XR strengths and whether FDA records assign a use code or identify the patent as covering the drug product, formulation, or method of use. A formulation patent can present an ANDA obstacle even when the active ingredient itself is long established.

What paragraph IV risks exist for generic oxcarbazepine?

An ANDA applicant challenging the patent would likely focus on three issues.

Lack of homogeneous matrix

The applicant could design a dosage form based on coated pellets, an osmotic system, a multiparticulate system, or a nonhomogeneous layered structure. The objective would be to deliver controlled release without using the claimed homogeneous matrix.

No claimed enteric release-promoting polymer

A generic developer could use a non-enteric release-control polymer, a mechanical membrane, an osmotic agent, or a pH-independent diffusion barrier. The product could still be extended release while avoiding the claimed enteric polymer limitation.

No separate solubility enhancer

The applicant could rely on particle-size reduction, salt formation, solid dispersion, amorphous oxcarbazepine, or another approach that does not use an excipient characterized as a solubility-enhancing agent. The boundary between a formulation excipient that improves wetting or hydration and one that legally "enhances solubility" could become a technical dispute.

The strongest patent challenge would likely combine non-infringement and invalidity arguments. Prior art may include earlier extended-release oxcarbazepine matrices, enteric polymers, solubility-enhancement techniques, and once-daily anticonvulsant formulations. Obviousness would turn on whether a skilled formulator would have combined those elements with a reasonable expectation of achieving the claimed pharmacokinetic effect.

How strong is the patent estate for Oxtellar XR?

The estate is stronger when evaluated as a portfolio rather than through Patent 11,166,960 alone. Supernus has used multiple patents and continuation applications around controlled-release oxcarbazepine formulations. The commercial protection may include overlapping composition, formulation, pharmacokinetic, and method claims.[2][3]

Estate characteristic	Assessment
Active ingredient protection	Weak as a standalone barrier because oxcarbazepine is old
Controlled-release formulation protection	Stronger, particularly where the product uses the claimed matrix architecture
600-mg strength protection	Narrow but commercially relevant
Once-daily protection	Useful as a secondary claim limitation
Enteric-polymer limitation	Creates a design-around route if a non-enteric system is feasible
Solubility-enhancer limitation	Creates another potential design-around route
Manufacturing-process protection	Not apparent from the claims supplied
Biosimilar protection	Not applicable
ANDA litigation risk	Material if the generic copies the formulation architecture

The estate’s practical strength depends on claim overlap, prosecution-history statements, dissolution data, formulation analytics, and the exact product composition disclosed in an ANDA. A generic applicant does not need to copy the brand’s trade dress or tablet appearance. It must avoid the enforceable claim limitations.

What patent litigation and settlement issues affect generic entry?

A paragraph IV dispute concerning Oxtellar XR would likely involve:

1. Whether the ANDA product has a homogeneous matrix;
2. Whether its polymer qualifies as a listed matrix-forming polymer;
3. Whether an excipient enhances oxcarbazepine solubility;
4. Whether an enteric polymer promotes release;
5. Whether the claims are anticipated or obvious;
6. Whether prosecution-history estoppel limits the doctrine of equivalents.

A settlement could provide a licensed launch date before patent expiration, a royalty-bearing supply arrangement, or a date tied to another patent in the Oxtellar XR estate. The commercial value of a settlement would depend on whether the generic applicant receives a license to all relevant patents or only to Patent 11,166,960.

No settlement terms can be inferred from the claim text alone. A reliable assessment requires the actual FDA patent listing, court docket, notice letter, complaint, and any filed settlement documents.

How does Oxtellar XR compare with other oxcarbazepine products?

Product type	Release profile	Principal regulatory route	Relevance to Patent 11,166,960
Trileptal immediate-release tablets	Immediate release	Original NDA and generic ANDAs	Generally outside the controlled-release matrix claims
Oxcarbazepine oral suspension	Immediate release	NDA and generic pathways	Generally outside the claimed tablet architecture
Oxtellar XR	Extended release, once daily	NDA 201004	Primary commercial product implicated
Future extended-release generic	Extended release	ANDA	Must address listed formulation patents
Biosimilar product	Not applicable	351(k)	Oxcarbazepine is not a biologic

The distinction between immediate-release oxcarbazepine and Oxtellar XR is central. Patent 11,166,960 does not restore exclusivity over oxcarbazepine generally. It protects a particular controlled-release formulation strategy.

What geographic coverage does the patent provide?

U.S. Patent 11,166,960 provides rights only in the United States. Corresponding international applications may have produced foreign patents with different claim scope, expiration dates, validity outcomes, and enforcement prospects. U.S. approval and Orange Book listing do not establish protection in Europe, Canada, Japan, or other markets.

For a global launch, the relevant analysis must separate:

• U.S. patent rights;
• European national validations;
• Canadian and Japanese formulation patents;
• Regulatory exclusivity in each jurisdiction;
• Local patent-linkage procedures;
• Local generic filing and launch rules.

What manufacturing and IP barriers remain after patent expiry?

After expiration of the relevant formulation claims, commercial entry may still depend on:

• Ability to reproduce the dissolution profile;
• Control of oxcarbazepine content uniformity;
• Stability of the matrix and enteric polymer;
• Demonstration of bioequivalence;
• FDA inspection and chemistry, manufacturing, and controls approval;
• Supply of specialized excipients;
• Additional unexpired continuation or improvement patents.

The patent does not claim a manufacturing process in the supplied claims. A process patent, if separately issued and listed or enforceable, could create a different risk profile. Patent expiry also does not remove FDA requirements for ANDA approval.

Key Takeaways

• Claim 1 covers a controlled-release oxcarbazepine formulation with a homogeneous polymer matrix, a solubility enhancer, and an enteric release-promoting polymer.
• The claim is broad across polymer classes but narrow in requiring the specific matrix-plus-solubility-enhancer-plus-enteric-polymer architecture.
• Claims 3 and 5 directly map to commercial attributes of Oxtellar XR: the 600-mg strength and once-daily administration.
• Claim 2 may be harder to enforce because it requires a pharmacokinetic performance characteristic.
• Generic competition would proceed through the ANDA pathway, with paragraph IV certification as the principal early-entry challenge mechanism.
• Biosimilar competition is irrelevant because oxcarbazepine is a small-molecule active ingredient.
• The expected base patent term reaches December 2027, subject to the official USPTO term calculation and any applicable adjustment.
• The most credible design-around routes are a nonhomogeneous dosage form, a non-enteric release-control system, or a formulation without a qualifying solubility-enhancing agent.
• The overall Oxtellar XR risk assessment must account for the full patent family, not Patent 11,166,960 in isolation.

FAQs

Is Patent 11,166,960 an oxcarbazepine composition-of-matter patent?

No. It is a formulation patent. It does not claim oxcarbazepine as a new chemical entity.

Does a 600-mg oxcarbazepine tablet automatically infringe the patent?

No. The 600-mg limitation appears in dependent claim 3. The product must also satisfy claim 1’s matrix, solubility-enhancer, and enteric-polymer requirements.

Can an immediate-release oxcarbazepine generic infringe Patent 11,166,960?

Generally, an immediate-release product would not satisfy the controlled-release and homogeneous-matrix limitations. It could still implicate other patents or regulatory requirements.

Is a pH-dependent coating alone enough to infringe the patent?

Not necessarily. The claimed enteric polymer must function as a release-promoting agent in a formulation that also contains the required homogeneous matrix and solubility enhancer.

What is the main invalidity vulnerability?

The principal vulnerability is an obviousness challenge based on earlier controlled-release oxcarbazepine matrices combined with known solubility-enhancing excipients and enteric polymers. The result would depend on the complete prior-art record and the patent’s prosecution history.

References

1. U.S. Food and Drug Administration. (2024). Oxtellar XR prescribing information. FDA.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
3. United States Patent and Trademark Office. (2021). U.S. Patent No. 11,166,960: Controlled-release formulation comprising oxcarbazepine. USPTO.
4. U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. FDA.
5. U.S. Code, 21 U.S.C. § 355(j)(2)(A)(vii), (j)(5)(B)(iii).

Drugs Protected by US Patent 11,166,960

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Supernus Pharms	OXTELLAR XR	oxcarbazepine	TABLET, EXTENDED RELEASE;ORAL	202810-001	Oct 19, 2012	AB	RX	Yes	No			Y
Supernus Pharms	OXTELLAR XR	oxcarbazepine	TABLET, EXTENDED RELEASE;ORAL	202810-002	Oct 19, 2012	AB	RX	Yes	No			Y
Supernus Pharms	OXTELLAR XR	oxcarbazepine	TABLET, EXTENDED RELEASE;ORAL	202810-003	Oct 19, 2012	AB	RX	Yes	Yes			Y

International Family Members for US Patent 11,166,960

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	E496623
Australia	2007242984
Canada	2597740
China	101489560
Germany	602007012236
European Patent Office	2026815
European Patent Office	2359830