United States Patent 9,566,259: Claims, Scope, Expiration, and Fumarate Patent Landscape

U.S. Patent No. 9,566,259 protects oral pharmaceutical formulations containing dimethyl fumarate, monomethyl fumarate, or related fumarate esters in a single-phase, non-aqueous liquid system. The strongest commercial scope is directed to enterically coated soft capsules containing fumarate ester, mono- and di-glycerides, polyoxyl 40 hydrogenated castor oil, polyvinylpyrrolidone, and lactic acid. The patent also covers dosage strengths approximating Tecfidera's 240 mg daily regimen, formulations bioequivalent to 240 mg of dimethyl fumarate, and a rotary-die encapsulation manufacturing process.

The patent has potential relevance to generic dimethyl fumarate products, monomethyl fumarate products, reformulated fumarate products, and liquid-filled soft-capsule delivery systems. Its principal limitations are the required non-aqueous liquid architecture, specified excipient ranges, capsule format in several claims, and functional bioequivalence language in claims 22-25.

What does U.S. Patent 9,566,259 cover?

The patent covers four related subject-matter groups:

Claim group	Claims	Principal subject matter
Broad composition claims	1-15	Oral immediate-release compositions containing fumarate ester in a single-phase non-aqueous liquid
Defined excipient compositions	16-21	Fumarate ester with mono- and di-glycerides, polyoxyl 40 hydrogenated castor oil, polyvinylpyrrolidone, and lactic acid
Bioequivalent compositions	22-25	Non-aqueous liquid suspension containing 90-220 mg fumarate ester and bioequivalent to 240 mg dimethyl fumarate
Manufacturing and product claims	26-29	Mixing, homogenization, film casting, rotary-die encapsulation, and optional enteric coating

The patent's commercial center of gravity is a liquid-filled soft capsule containing dimethyl fumarate or monomethyl fumarate. The claims do not broadly cover every oral fumarate formulation. A conventional tablet, dry powder capsule, or aqueous solution generally would not satisfy the principal structural limitations without additional claim-construction findings.

What are the key limitations in claim 1?

Claim 1 requires all of the following:

An oral pharmaceutical composition.
Immediate release.
A single-phase non-aqueous liquid.
Dimethyl fumarate, monomethyl fumarate, a monomethyl fumarate prodrug, or a combination.

The claim is drafted as a composition claim rather than a method-of-treatment claim. Infringement would generally turn on whether an accused product contains the claimed formulation, regardless of whether the manufacturer adopts the patent's terminology in labeling.

"Single-phase" is significant. A formulation with visible phase separation, a conventional emulsion, or a suspension with a separate solid phase may create noninfringement arguments. Claim 22 separately refers to a "single-phase non-aqueous liquid suspension," creating a potential construction issue because a true suspension ordinarily contains dispersed solid particles and is not fully single phase.

"Immediate release" also requires careful analysis. Claims 11 and 12 depend from claim 1 but recite an enterically coated capsule providing delayed release. The patent therefore contains an apparent tension between immediate-release composition language and delayed-release capsule language. A court could construe immediate release as rapid release after the enteric barrier opens, but the inconsistency creates litigation risk for both sides.

How broad are claims 2 through 15?

Claims 2 through 15 narrow claim 1 through dose, excipient, ratio, dosage form, active ingredient, and pharmacological-effect limitations.

Claims	Limitation	Scope effect
2	Approximately 90-110 mg or 180-220 mg fumarate ester	Targets 100 mg and 200 mg unit strengths
3	Lipid or lipophilic liquid	Expands the liquid vehicle beyond a named formulation
4	Mono- and di-glycerides, PVP, polyoxyl 40 hydrogenated castor oil, lactic acid	Identifies a specific excipient platform
5-6	Fumarate-to-liquid ratio of 1:1 to 1:8, including about 1:2	Creates quantitative formulation limitations
7-8	Weight percentages for ester and liquid	Provides overlapping composition ranges
9	30-40% ester, 55-65% liquid, 5% lactic acid	Narrow formulation "recipe"
10-12	Capsule and enterically coated soft capsule	Focuses on oral capsule delivery
13-14	Dimethyl fumarate or monomethyl fumarate	Removes some Markush breadth
15	Activation of the Nrf2 pathway	Adds a biological-effect limitation

Claims 4, 9, and 16 are the most important for formulation-specific enforcement. They give a patentee a narrower fallback position if the broader single-phase liquid claims are challenged for lack of written description, enablement, or anticipation.

What formulations are protected by claims 16 through 21?

Claim 16 recites a defined composition containing:

Component	Claimed range
One or more fumarate esters	12%-40% by weight
Mono- and di-glycerides	50%-80%
Polyoxyl 40 hydrogenated castor oil	5%-15%
Polyvinylpyrrolidone	1%-5%
Lactic acid	1%-5%

Claims 17-20 narrow the formulation by dose, active ingredient, and enterically coated soft-capsule presentation. Claim 21 adds an in vitro dissolution limitation of approximately 50% dissolution after 30 minutes at pH 6.8.

This claim set is materially narrower than claim 1. A competing product could potentially avoid claim 16 by changing one excipient, moving outside a claimed percentage range, using a different surfactant or viscosity modifier, or adopting a solid dosage form. The doctrine of equivalents could still create exposure where the substitution performs substantially the same function in substantially the same way, but numerical-range claims generally provide stronger design-around opportunities than broad composition claims.

The dissolution limitation in claim 21 may be valuable in distinguishing products with different release profiles. It also creates testing and batch-to-batch evidence issues. Infringement analysis would likely require validated dissolution data under the specified pH, time, apparatus, temperature, agitation, and sampling conditions.

What do claims 22 through 25 protect?

Claims 22-25 target a composition containing approximately 90-220 mg of fumarate ester that is bioequivalent to a 240 mg dimethyl fumarate dose.

Claim 24 captures three dosing patterns:

Two approximately 90-110 mg doses administered twice daily.
One approximately 90-110 mg dose administered four times daily.
One approximately 180-220 mg dose administered twice daily.

The claim is designed to cover regimens that reproduce the exposure associated with a 240 mg dimethyl fumarate dose, even where the unit strength or active fumarate differs.

This claim set creates two legal questions. First, bioequivalence is a functional limitation that may require pharmacokinetic evidence. Second, claim 22 combines "single-phase" and "suspension" terminology. An accused manufacturer could argue that its product is a multiphase suspension and therefore falls outside the single-phase requirement. The patent owner could argue that "single-phase" describes the liquid vehicle while the fumarate ester is dispersed within that vehicle.

The claims also raise a potential issue under 35 U.S.C. § 112 if the specification does not provide adequate guidance for the full range of fumarate esters, dose levels, liquid vehicles, and bioequivalent outcomes recited in the claims. The patent's narrower examples and specific excipient claims would likely be more resilient than the broad functional genus.

What manufacturing process is protected by claims 26 through 29?

Claim 26 covers a process with five required operations:

Mixing lactic acid with a single-phase non-aqueous liquid.
Adding fumarate ester and homogenizing.
Preparing a gel mass with a water-soluble film-forming polymer, plasticizer, and solvent.
Casting the gel into films or ribbons using heated drums or surfaces.
Encapsulating the homogenized formulation by rotary-die encapsulation.

Claim 27 adds enteric coating. Claims 28 and 29 cover dosage forms produced by the process.

The process claim is commercially important because it reaches manufacturing conduct rather than only the finished formulation. A manufacturer using a different encapsulation process, such as hard-shell filling, vacuum filling, or a different film-forming operation, may avoid literal infringement of claim 26. Claim 28 could still create product-by-process exposure if the finished dosage form is materially indistinguishable and the product-by-process limitation is interpreted as limiting the claim.

The manufacturing claims also create possible supply-chain exposure for contract manufacturers, capsule producers, and developers licensing a soft-capsule platform.

When does U.S. Patent 9,566,259 expire?

The patent is associated with a 2013 priority date and a 20-year U.S. patent term calculated from the relevant nonprovisional or international filing framework. Its nominal expiration is approximately May 30, 2034, subject to the actual patent-term calculation, patent-term adjustment, terminal disclaimers, and any applicable statutory adjustment recorded by the USPTO.

Event	Date or period
Earliest identified priority	May 30, 2013
U.S. patent grant	2017
Nominal term	Approximately 20 years from the applicable filing date
Approximate expiration	May 30, 2034
Patent-term extension	No extension is established from the claim information provided

A patent expiration analysis should distinguish this patent from FDA regulatory exclusivity. Patent term and FDA exclusivity are separate rights. A patent can remain in force after FDA exclusivity expires, and FDA approval does not itself establish infringement.

What is the Orange Book status of U.S. Patent 9,566,259?

The Orange Book listing status of U.S. Patent 9,566,259 is product-specific. The patent does not automatically become an Orange Book-listed patent merely because it covers dimethyl fumarate, monomethyl fumarate, or a product bioequivalent to Tecfidera.

For Orange Book listing, the patent generally must claim the approved drug, an approved formulation or composition, or an approved method of use, and the NDA holder must submit it under FDA listing rules. Composition and formulation claims may be listable when they read on the approved product. A manufacturing-only claim normally presents a different listing analysis.

The key comparison is:

Patent subject	Typical Orange Book relevance
Approved active ingredient	Potentially listable if properly submitted
Approved formulation or composition	Potentially listable
Approved method of use	Potentially listable
Manufacturing process only	Generally weaker listing basis
Experimental or unapproved formulation	Usually not relevant to the approved product listing

Tecfidera's established patent estate has included patents directed to dimethyl fumarate products and methods of treating multiple sclerosis. U.S. Patent 9,566,259 should not be treated as part of the Tecfidera Orange Book barrier without confirmation in the current FDA publication and the relevant NDA patent submissions. [2]

Which companies face the greatest patent exposure?

The highest exposure is for companies developing products with the following profile:

Dimethyl fumarate or monomethyl fumarate.
Liquid-filled soft capsules.
Enteric coating.
Mono- and di-glyceride vehicle.
Polyoxyl 40 hydrogenated castor oil.
Polyvinylpyrrolidone and lactic acid.
Unit doses near 100 mg or 200 mg.
Bioequivalence to a 240 mg dimethyl fumarate dose.

Potentially exposed parties include generic manufacturers seeking approval for dimethyl fumarate, developers of monomethyl fumarate products, specialty pharmaceutical companies using liquid-filled capsule technology, and contract manufacturers applying the claimed rotary-die process.

Companies using conventional delayed-release hard capsules, compressed tablets, dry granules, or materially different excipient systems face lower literal exposure under claims 16-21. They may still face the broader claims 1-3 and 22 if their products use a single-phase non-aqueous liquid system and satisfy the dose or bioequivalence limitations.

What Paragraph IV challenges could target this patent?

A Paragraph IV certification could challenge the patent on several grounds:

Challenge	Likely target
Anticipation	Earlier liquid fumarate formulations, soft capsules, or excipient systems
Obviousness	Combination of known dimethyl fumarate formulations with lipid vehicles and enteric capsules
Written description	Broad coverage of multiple fumarate esters, prodrugs, vehicles, doses, and bioequivalence outcomes
Enablement	Ability to make the full claimed genus without undue experimentation
Indefiniteness	"Single-phase," "immediate release," "about," and "bioequivalent" language
Noninfringement	Different phase structure, dosage form, excipients, process, or dissolution profile

A Paragraph IV notice could trigger litigation under the Hatch-Waxman Act and a potential 30-month stay if the patent were properly listed against the relevant NDA. The commercial importance of the patent would depend heavily on whether it is listed for the target reference product and whether the proposed generic's formulation actually falls within the asserted claims. [3]

How strong is the patent estate?

The estate is strongest against a formulation that copies the disclosed platform. Its strength declines as a developer moves away from the specified liquid vehicle and capsule process.

Risk factor	Assessment
Broad active-ingredient coverage	Moderate
Single-phase non-aqueous liquid limitation	Moderate to strong
Specific excipient formulation	Strong against close copies
Dose-range coverage	Moderate
Bioequivalence claim	Fact-dependent and potentially vulnerable
Enteric soft-capsule coverage	Strong for matching products
Manufacturing-process coverage	Strong only where process steps are replicated
Design-around potential	Meaningful

The patent has layered claims. If claims 1 or 22 are narrowed or invalidated, claims 4, 9, 16, and 26 may preserve narrower enforcement positions. That structure increases litigation complexity but does not eliminate design-around opportunities.

How does this patent compare with the broader dimethyl fumarate landscape?

The broader dimethyl fumarate landscape includes at least four patent categories:

Composition and active-ingredient patents.
Polymorph, crystal-form, and solid-state patents.
Treatment-method patents for multiple sclerosis and other inflammatory or neurodegenerative conditions.
Formulation and delivery patents, including delayed-release capsules and liquid-filled systems.

Tecfidera-related litigation has historically focused on the validity and scope of patents covering dimethyl fumarate treatment and product characteristics. Vumerity and Bafiertam add separate estates directed to diroximel fumarate and monomethyl fumarate, respectively. Those products are not automatically captured by every dimethyl fumarate patent because their active ingredients, metabolites, formulations, and regulatory approvals differ.

U.S. Patent 9,566,259 is most relevant to formulation competition rather than to every oral fumarate product. Its practical value is highest where a competitor seeks to reproduce a liquid-filled, enterically coated soft-capsule platform.

What generic launch scenarios exist?

Launch after patent expiration

A generic manufacturer could launch after the relevant patent expires, assuming FDA approval and no other enforceable patent or regulatory exclusivity barrier. For this patent, the expected timing is approximately 2034 based on the identified priority framework.

Paragraph IV launch

A Paragraph IV applicant could launch before expiration if it obtains a favorable judgment, reaches a settlement permitting launch, or accepts litigation risk. The applicant would need to address both this patent and other active patents covering the reference product.

Formulation design-around

A lower-risk strategy could use:

A hard capsule instead of a soft capsule.
A dry granulation or tablet.
A different lipid vehicle.
Different surfactant and polymer selections.
A formulation outside the claimed numerical ranges.
A non-enteric dosage form.
A process not using rotary-die encapsulation.

Each strategy requires claim-by-claim testing. Changing one ingredient may avoid claim 16 while leaving exposure under claim 1 or claim 22.

What licensing and settlement issues matter?

No licensing deal or settlement agreement can be inferred from the claims alone. The relevant commercial question is whether the patent owner licensed the formulation platform to a product sponsor, capsule manufacturer, or generic applicant.

A settlement involving this patent could include:

A delayed generic launch date.
A license to use the liquid formulation.
A manufacturing authorization.
Restrictions on soft-capsule or enteric technology.
A covenant not to sue limited to a specified product.
A supply or co-development arrangement.

A settlement covering one fumarate product would not necessarily resolve exposure for another product, particularly where the active ingredient or formulation differs.

Key Takeaways

U.S. Patent 9,566,259 is directed primarily to liquid-filled oral fumarate formulations, especially enterically coated soft capsules.
The broadest claim requires a single-phase non-aqueous liquid containing dimethyl fumarate, monomethyl fumarate, a related prodrug, or a combination.
Claims 16-21 provide the strongest formulation-specific protection through defined excipient ranges and dissolution performance.
Claims 22-25 target products and dosing regimens bioequivalent to 240 mg of dimethyl fumarate.
Claims 26-29 protect a manufacturing route using homogenization, film casting, and rotary-die encapsulation.
The approximate patent-term endpoint is May 30, 2034, subject to the official USPTO term calculation.
Orange Book relevance is product-specific and cannot be assumed solely from the patent's coverage of fumarate esters.
The most credible design-arounds involve changing the dosage form, liquid vehicle, excipient system, phase structure, or manufacturing process.
Generic launch risk depends on this patent together with the separate Tecfidera, Vumerity, and Bafiertam patent estates.

Frequently Asked Questions

Does U.S. Patent 9,566,259 cover Tecfidera tablets or capsules generally?

No. The claims focus on specific non-aqueous liquid formulations and, in several claims, soft or enterically coated soft capsules. A conventional dimethyl fumarate dosage form is not automatically covered.

Does the patent cover monomethyl fumarate products?

Yes. Several claims expressly recite monomethyl fumarate, either alone or with dimethyl fumarate. Coverage still depends on satisfying the remaining structural, dosage, phase, and formulation limitations.

Can a generic avoid the patent by using a hard capsule?

Potentially. A hard capsule may avoid claims limited to soft or enterically coated soft capsules, but claims 1-9 and 22-25 may remain relevant if the hard capsule contains the claimed non-aqueous liquid and satisfies the applicable dose or bioequivalence limitations.

Is a product bioequivalent to Tecfidera automatically infringing?

No. Bioequivalence alone does not establish infringement. The product must also meet the claimed composition, phase, dose, active-ingredient, and dosage-form limitations.

Does the patent block all Nrf2-activating fumarate therapies?

No. The Nrf2 limitation appears in dependent claims. A product that activates Nrf2 but does not contain the claimed liquid formulation, dose, capsule, or process would not automatically infringe.

References

United States Patent and Trademark Office. (2017). U.S. Patent No. 9,566,259, Pharmaceutical compositions comprising fumarate esters.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
United States Code. (2023). 21 U.S.C. § 355(j): Abbreviated applications and patent certifications.
United States Code. (2023). 35 U.S.C. §§ 102, 103, 112, and 271: Patentability, disclosure, and infringement.
U.S. Food and Drug Administration. (2024). Guidance for industry: Abbreviated new drug application submissions and the listed drug.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Banner Life Sciences	BAFIERTAM	monomethyl fumarate	CAPSULE, DELAYED RELEASE;ORAL	210296-001	Apr 28, 2020		RX	Yes	Yes	9,566,259	⤷ 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

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2015222880	⤷ Start Trial
Australia	2015328676	⤷ Start Trial
Australia	2016253548	⤷ Start Trial
Australia	2017204505	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,566,259

Which drugs does patent 9,566,259 protect, and when does it expire?

Summary for Patent: 9,566,259