United States Patent 11,364,247: Eslicarbazepine Acetate Dosing Claims, Expiration, and Patent Landscape

U.S. Patent No. 11,364,247 protects once-daily administration of eslicarbazepine acetate for epilepsy, including refractory epilepsy and adjunctive therapy. Its core coverage is a dose-and-regimen method patent, not a composition, formulation, manufacturing, or chemical-structure patent. The principal commercial relevance is Aptiom, Sunovion Pharmaceuticals’ eslicarbazepine acetate product.

The patent’s broadest claims cover once-daily doses from approximately 400 mg to 2,400 mg. The dependent claims narrow the scope to specific doses, oral dosage forms, dose escalation, refractory patients, adjunctive use, selected concomitant antiepileptic drugs, and preservation of serum concentrations of the concomitant drug.

What does U.S. Patent 11,364,247 cover?

The patent covers a human treatment method requiring all of the following elements:

A patient with epilepsy or refractory epilepsy.
Once-daily administration.
Eslicarbazepine acetate.
A dose of approximately 400 mg to approximately 2,400 mg.
For refractory-epilepsy claims, refractoriness to at least one other antiepileptic drug.
For adjunctive-treatment claims, concurrent treatment with another antiepileptic drug.

Independent claim 1 covers treatment of epilepsy generally:

Once-daily administration of about 400 mg to about 2,400 mg of eslicarbazepine acetate to a human patient.

Independent claim 11 is narrower because it requires refractory epilepsy and resistance to at least one other antiepileptic drug.

Claim group	Subject matter	Commercial significance
Claims 1-10	Epilepsy treatment using once-daily eslicarbazepine acetate	Broadest dosing-regimen protection
Claims 11-22	Refractory epilepsy treatment	Targets the principal clinical use of Aptiom
Claims 2-7 and 15-20	Dose ranges and fixed doses	Covers 400, 800, 1,200 and 1,600 mg regimens
Claims 8 and 21	Tablets or oral suspensions	Covers common oral dosage forms
Claims 9 and 10	Seizure reduction and dose escalation	Adds treatment-response and titration limitations
Claims 12-14	Adjunctive therapy and drug-interaction limitation	Relevant to polytherapy with other antiepileptic drugs
Claim 22	Initial 400 mg dose followed by titration	Corresponds closely to clinical dosing practice

The claim set does not expressly require a particular tablet composition, release mechanism, polymorph, particle size, excipient, manufacturing process, pharmacokinetic profile, or blood concentration of eslicarbazepine.

How broad are the dose claims in Patent 11,364,247?

The broadest numerical scope is approximately 400 mg to approximately 2,400 mg once daily. Claims 2 and 3 create overlapping subranges:

Claim 2: at least approximately 800 mg.
Claim 3: approximately 800 mg to approximately 1,600 mg.
Claims 4-7: approximately 400, 800, 1,200 and 1,600 mg.
Claims 15-20: corresponding doses for refractory epilepsy.

The claims use “about,” which introduces a potential claim-construction issue. The term generally allows a commercially and clinically reasonable variation around the stated amount, but its exact scope depends on the specification, prosecution history, and evidence concerning dose equivalence.

A product administered at 2,400 mg once daily appears within claim 1 if the dose is treated as approximately 2,400 mg. Claim 10 expressly includes escalation to 2,400 mg, while claim 22 stops at 1,600 mg for the refractory-epilepsy regimen.

What does “once-daily” require?

The central limitation is administration once daily. A generic or other competitor using a twice-daily regimen would have a materially different non-infringement position under these claims, although other patents or regulatory restrictions could still apply.

A once-daily total daily dose divided into multiple administrations would not ordinarily satisfy the literal “once-daily” limitation. The analysis would depend on the product labeling, actual instructions, prescribing practice, and any doctrine-of-equivalents theory.

Does the patent cover all eslicarbazepine acetate products?

No. The claims cover specified therapeutic administration, not every product containing eslicarbazepine acetate. A competitor could potentially practice outside the claims by:

Using a different dosing frequency;
Using a dose outside the claimed range;
Selling the active ingredient for a non-epilepsy indication, if legally and clinically applicable;
Selling a product without promoting the claimed use, subject to induced-infringement risk;
Challenging validity or enforceability of the patent.

The patent does not by itself prevent manufacture or sale of eslicarbazepine acetate after expiration of earlier composition or product patents.

What patient populations are protected?

Claims 1-10 apply to human epilepsy patients without expressly requiring refractory disease. Claims 11-22 are narrower and require refractory epilepsy.

Claim 11 defines the relevant patient by requiring refractoriness to at least one other antiepileptic drug. Claim 12 further requires adjunctive therapy with at least one other antiepileptic drug. Claim 13 identifies the following drugs:

Phenytoin
Valproate
Primidone
Phenobarbital
Lamotrigine
Gabapentin
Topiramate
Clonazepam
Combinations of those drugs

Claim 14 requires that the serum concentration of the other antiepileptic drug not be significantly decreased by eslicarbazepine acetate. This limitation may be difficult to apply in practice because “not significantly decreased” requires a clinically or statistically meaningful comparator and relevant serum-concentration data.

What formulations are protected by Patent 11,364,247?

Claims 8 and 21 identify tablets and oral suspensions. These claims are dosage-form limitations within treatment methods. They do not claim a particular tablet formulation or suspension composition.

The patent therefore provides limited formulation protection:

Formulation issue	Coverage under Patent 11,364,247
Eslicarbazepine acetate tablet used once daily	Covered if all method limitations are met
Oral suspension used once daily	Covered under claims 8 and 21 if all other limitations are met
Specific excipient system	Not expressly claimed
Extended-release technology	Not expressly claimed
Tablet hardness, coating or dissolution profile	Not expressly claimed
Manufacturing process	Not claimed
Chemical composition of eslicarbazepine acetate	Not claimed

A generic tablet could infringe the method claims if its approved labeling instructs once-daily use within the claimed dose range. The generic’s formulation itself would not need to be identical to Aptiom’s formulation.

What is the FDA status of eslicarbazepine acetate?

The FDA approved Aptiom under NDA 206375 on November 8, 2013, for adjunctive therapy in the treatment of partial-onset seizures in patients four years of age and older. The product contains eslicarbazepine acetate and is administered orally, generally once daily. The FDA label identifies 400 mg as an initial dose for adults, with maintenance doses commonly ranging from 800 mg to 1,600 mg once daily. [1]

The patent claims track the product’s labeled dosing architecture, particularly the 400 mg starting dose and 800 mg to 1,600 mg maintenance range.

FDA milestone	Date or status
Aptiom approval	November 8, 2013
Original indication	Adjunctive treatment of partial-onset seizures
Current pediatric scope	Patients four years of age and older, according to FDA labeling
Dosage form	Oral tablets
Core labeled schedule	Once daily
Typical adult maintenance range	800 mg to 1,600 mg once daily

The distinction between the patent’s “epilepsy” language and the FDA label’s “partial-onset seizures” language matters. The patent’s claims are drafted broadly, but regulatory labeling, clinical evidence, and written promotional materials may affect infringement and validity arguments.

What is the Orange Book status of U.S. Patent 11,364,247?

U.S. Patent 11,364,247 is associated with the Aptiom patent estate and covers a method of using eslicarbazepine acetate. Orange Book treatment of method-of-use patents can affect abbreviated new drug application certification requirements and the scope of any use code submitted by the NDA holder. The FDA Orange Book should be read together with the patent’s listed use code and any current patent-status updates. [2]

The patent was issued on June 21, 2022. Its nominal patent term is tied to the underlying family priority and is generally expected to expire in 2027, subject to any patent-term adjustment or applicable pediatric extension. The relevant commercial date is the operative expiration date reported in the current Orange Book and USPTO patent record.

Patent	Subject	Issue date	Expected nominal expiry
U.S. 11,364,247	Once-daily eslicarbazepine acetate treatment	June 21, 2022	2027, based on the underlying family term

A patent grant date does not establish a new 20-year term. A continuation patent can issue late in the family term while retaining an expiration date based on the earliest effective nonprovisional filing.

When does eslicarbazepine acetate lose exclusivity?

Aptiom’s commercial exclusivity depends on several separate rights:

Regulatory exclusivity under the Food, Drug, and Cosmetic Act.
Orange Book-listed patents.
Earlier compound, formulation, or method-of-use patents.
Pediatric exclusivity, if granted.
The timing and outcome of generic ANDA litigation.

The original five-year new chemical entity exclusivity associated with Aptiom has expired. The remaining barrier is therefore principally patent-based rather than NCE exclusivity-based.

The method patent’s expected nominal expiry in 2027 is not necessarily the earliest date on which a generic can launch. A generic applicant could launch earlier after:

A successful Paragraph IV challenge;
A court judgment of invalidity or noninfringement;
Settlement with the patent holder;
Certification to patents not covering the proposed generic use;
Approval with a permissible skinny label that omits patented use information.

Which companies are challenging Aptiom patents?

The supplied claim set does not identify a specific ANDA filer, Paragraph IV notice, or litigation docket. Patent 11,364,247 alone does not establish that a challenge has been filed.

The relevant potential challengers are generic manufacturers seeking approval for eslicarbazepine acetate tablets. Their strategies would likely include:

Paragraph IV certification against listed method-of-use patents;
Section viii statements carving out patented indications or dosing instructions;
Invalidity challenges based on obviousness, anticipation, written description, enablement, or indefiniteness;
Noninfringement positions based on label design or dosing frequency.

A Paragraph IV notice would create a potential 45-day period for the NDA holder or patent owner to file suit, which could trigger a statutory 30-month stay of ANDA approval under applicable conditions. [3]

What generic entry risks exist?

The principal generic-entry risk is that the patent claims cover ordinary clinical dosing rather than a technically complex delivery system. A generic applicant may be able to manufacture a conventional tablet while focusing its legal challenge on the method claims.

Scenario 1: Full-label generic launch after patent expiry

A generic applicant obtains approval for the same epilepsy indication and once-daily dosing after the relevant patents expire. This is the lowest litigation-risk pathway but may result in rapid price erosion.

Scenario 2: Paragraph IV challenge

The applicant argues that the claims are invalid or not infringed. The key validity issues could include:

Obviousness of once-daily dosing at known clinical doses;
Prior-art disclosure of eslicarbazepine acetate for epilepsy;
Written-description support for the full 400 mg to 2,400 mg range;
Enablement of the entire dose range and patient population;
Definiteness of “about” and “not significantly decreased”;
Patentable distinction between once-daily dosing and prior art dosing schedules.

Scenario 3: Skinny-label launch

A generic applicant omits patented method-of-use information from its labeling under a Section viii statement. The commercial value of this route depends on whether the remaining label still instructs once-daily administration for an unpatented use. Because claim 1 is broadly drafted to epilepsy treatment, a skinny-label strategy may face greater complexity than one involving a narrowly defined indication.

Scenario 4: Noninfringing dosing label

A competitor could seek a label that does not recommend the claimed once-daily dose range. This approach may reduce induced-infringement exposure but could also reduce clinical and commercial substitutability.

How strong is the patent estate for eslicarbazepine acetate?

Patent 11,364,247 is strongest against a product that:

Is labeled for epilepsy;
Instructs once-daily use;
Uses 400 mg to 2,400 mg;
Includes refractory or adjunctive therapy;
Uses tablets or oral suspension;
Includes a 400 mg titration schedule.

Its weaknesses are structural:

It is a late-issued continuation or family member with a limited remaining term.
It does not claim the active molecule itself.
It does not claim a distinctive formulation.
Its clinical dosing ranges may face obviousness arguments.
Several dependent claims repeat dose limitations already substantially encompassed by claim 1 or claim 11.
The refractory and adjunctive limitations may narrow enforcement to labeling and actual-use evidence.

The patent is therefore commercially relevant but not a standalone compound moat.

What licensing deals affect eslicarbazepine acetate?

Eslicarbazepine acetate originated with BIAL-Portela & Ca. S.A. and was commercialized in the United States by Sunovion Pharmaceuticals under a collaboration or license arrangement. Sunovion became part of Sumitomo Pharma through the corporate ownership history of Dainippon Sumitomo Pharma. [4]

The existence of a license or collaboration does not change the claim scope of Patent 11,364,247. It can affect:

Patent ownership and standing;
The identity of the party authorized to sue;
Royalty obligations;
Control of Orange Book listings;
Settlement authority in Paragraph IV litigation;
Allocation of U.S. and international rights.

What litigation or settlement issues are material?

The principal litigation issues would concern infringement of method claims and validity of the dosing regimen.

Issue	Likely question
Direct infringement	Does a patient perform the claimed administration method?
Induced infringement	Does the generic label encourage once-daily use within the claimed range?
Declaratory relief	Can a generic obtain a judgment before launch?
Obviousness	Would once-daily dosing and the claimed dose range have been routine?
Anticipation	Did earlier epilepsy treatment disclosures disclose the same regimen?
Enablement	Does the specification support the complete range and all claimed patients?
Definiteness	Are “about” and “not significantly decreased” sufficiently clear?
Regulatory carve-out	Can the generic omit the patented use without retaining the claimed method?

No settlement terms can be inferred from the patent grant or claim text. Any launch date negotiated between the patent owner and a generic applicant would require a separate settlement, consent judgment, or publicly reported litigation record.

Is there biosimilar risk for eslicarbazepine acetate?

No traditional biosimilar pathway applies. Eslicarbazepine acetate is a small-molecule drug, not a biologic subject to the Biologics Price Competition and Innovation Act. The relevant competitors are ANDA applicants for generic eslicarbazepine acetate, not biosimilar applicants under the Purple Book. [5]

The main competitive risks are generic substitution, therapeutic substitution within the antiepileptic market, and price competition after patent barriers fall.

How does Patent 11,364,247 compare with composition and formulation patents?

Patent category	Protection	Relevance to generic entry
Compound patent	Chemical molecule or active ingredient	Usually the strongest barrier, but not the focus of these claims
Formulation patent	Tablet, suspension, release profile, or excipient system	Can block a specific product design
Method-of-use patent	Dose, schedule, patient population, or indication	Depends heavily on labeling and induced infringement
Manufacturing patent	Synthesis, purification, crystallization, or process	May require process redesign
Patent 11,364,247	Once-daily treatment regimen	Significant for labeled use, limited for off-label or noninfringing regimens

Patent 11,364,247 does not prevent a manufacturer from developing an alternative synthesis or formulation. It primarily creates a use-based barrier around the FDA-recognized once-daily treatment pattern.

Key Takeaways

U.S. Patent 11,364,247 is a method-of-treatment patent for once-daily eslicarbazepine acetate.
Its broadest dose range is approximately 400 mg to 2,400 mg once daily.
Claims 11-22 narrow coverage to refractory epilepsy, adjunctive therapy, listed concomitant drugs, and related dosing features.
The patent does not claim the active molecule, a specific tablet formulation, or a manufacturing process.
Aptiom was FDA-approved in 2013 for adjunctive treatment of partial-onset seizures.
The patent’s nominal term is expected to end in 2027, subject to the operative USPTO and Orange Book term.
Generic applicants could pursue Paragraph IV, Section viii, noninfringement, or post-expiry launch strategies.
No biosimilar pathway applies because eslicarbazepine acetate is a small-molecule drug.
The estate is commercially relevant for labeled once-daily use but weaker than a compound or formulation estate.
Claim 14’s “not significantly decreased” limitation and the use of “about” create potential construction and proof issues.

FAQs About U.S. Patent 11,364,247

Does Patent 11,364,247 cover Aptiom itself?

No. It covers specified once-daily treatment methods using eslicarbazepine acetate. It does not independently claim every Aptiom tablet or the eslicarbazepine acetate molecule.

Can a generic sell eslicarbazepine acetate before 2027?

Potentially, but the pathway would depend on the complete patent list, Paragraph IV litigation, any settlement, applicable regulatory exclusivity, and the approved generic label.

Does a twice-daily eslicarbazepine acetate product infringe these claims?

A twice-daily regimen would not literally satisfy the once-daily limitation. Other patents, labels, or infringement theories could still be relevant.

Are 400 mg, 800 mg, 1,200 mg and 1,600 mg separately protected?

Yes. Claims 4-7 and 17-20 identify those doses expressly, while the broader independent claims also encompass them.

Is a new oral suspension protected by the patent?

Only when used in a claimed once-daily treatment method. The patent does not claim the suspension’s excipients, manufacturing process, or physical formulation as an independent product.

References

U.S. Food and Drug Administration. (2013). Aptiom (eslicarbazepine acetate) prescribing information.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2024). Abbreviated new drug application approvals and patent certifications.
BIAL-Portela & Ca., S.A., & Sunovion Pharmaceuticals Inc. (2013). Eslicarbazepine acetate commercialization and development materials.
U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products.
U.S. Patent and Trademark Office. (2022). U.S. Patent No. 11,364,247, Methods of treating epilepsy.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	055939	⤷ Start Trial
Australia	2005331690	⤷ Start Trial
Brazil	PI0520258	⤷ Start Trial
Canada	2607427	⤷ Start Trial
Mexico	2007013882	⤷ Start Trial
Mexico	366496	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 11,364,247

Summary for Patent: 11,364,247