US Patent 10,987,341: Edaravone Oral Suspension Claims, Expiration, Orange Book Status and Patent Landscape

US Patent 10,987,341 protects an edaravone oral suspension in which solid edaravone particles remain dispersed in water through specified dispersants. The broadest composition claims cover edaravone concentrations of 0.5% to 36% w/v with polyvinyl alcohol, methylcellulose, hypromellose, sucrose fatty acid ester or polysorbate. Dependent claims add viscosity, particle-size, dissolution, pharmacokinetic, bioequivalence and dosing limitations.

The patent is commercially relevant to Radicava ORS, Mitsubishi Tanabe Pharma Corporation’s oral edaravone product for amyotrophic lateral sclerosis, or ALS. Its principal value is formulation protection for a liquid oral product rather than protection of edaravone as an active ingredient.

What does US Patent 10,987,341 protect?

The patent claims a water-based suspension containing:

Edaravone particles in solid form.
Water.
At least one specified dispersant.
An edaravone concentration of 0.5% to 36% w/v.

The claims do not cover every liquid edaravone formulation. A potentially infringing product must satisfy the required composition and, for narrower claims, the applicable physical or clinical limitations.

Claim group	Primary subject matter	Principal limitation
Claims 1-6	Core edaravone suspension	Specified dispersant and, in some claims, polyvinyl alcohol characteristics
Claims 7-10, 23-25	Thickened suspension	Xanthan gum or tragacanth powder
Claims 11-16	Physical and performance characteristics	Particle size, viscosity, density and dissolution
Claims 17-19	Pharmacokinetic and comparative bioavailability profile	Cmax, AUC and crossover comparison with edaravone injection
Claim 20	ALS therapeutic agent	1-20 mL dose containing 50-210 mg edaravone
Claims 21-22	Dispersant concentration	0.001% to 1.0% w/v, including polyvinyl alcohol

The claim set has two distinct protection layers. Claims 1-16 and 21-25 are principally composition claims. Claims 17-19 add clinical-performance limitations. Claim 20 links the suspension to a dose regimen and ALS treatment.

What is the scope of independent claim 1?

Claim 1 is the central formulation claim. It requires five material elements:

An edaravone suspension for human oral administration.
Water.
Edaravone particles dispersed in the water.
A dispersant that maintains the edaravone in a solid particle state.
Edaravone at 0.5% to 36% w/v.

The dispersant must be at least one of the following:

Polyvinyl alcohol.
Methylcellulose.
Hypromellose.
Sucrose fatty acid ester.
Polysorbate.

The claim is broad as to the identity of the thickening agent, sweetener, stabilizer, pH regulator and other excipients. It is narrower as to the dispersant class and the requirement that edaravone remain as solid particles rather than dissolve completely or form a molecular solution.

The 0.5% to 36% w/v range is expansive. Radicava ORS contains 105 mg of edaravone in 5 mL, equivalent to approximately 2.1% w/v, which falls within the claimed concentration range according to the FDA-approved product labeling (U.S. Food and Drug Administration, 2022).

How do the dependent claims narrow the patent?

Claims 2-6 limit the dispersant selection. Claim 5 is particularly formulation-specific. It requires polyvinyl alcohol with:

A saponification degree of 86.5 to 89.0.
A kinematic viscosity of 3 to 55.7 mm²/s for a 4% aqueous solution at 20°C.

These parameters can materially narrow infringement analysis. A competitor using polyvinyl alcohol outside either range may avoid literal infringement of claim 5, although claims 1-4 or 21-22 could remain relevant.

Claims 7-10 and 23-25 add a thickening agent. The specified agents are xanthan gum and tragacanth powder. Claim 9 narrows this further to xanthan gum. Claim 10 requires 0.1% to 1.2% w/v thickening agent.

Claim 11 covers a particle-size profile:

D50 of 10 to 100 micrometers.
D90 of 50 to 300 micrometers.

This limitation creates potential design-around space through particle engineering, but particle-size measurements can be method-sensitive. An infringement dispute would likely examine the analytical method, sample preparation, aggregation and measurement conditions.

Claims 14-16 impose product-performance limitations:

Viscosity of 50 to 1,750 mPa·s.
Density of 1.0 to 1.5 g/mL.
At least 80% edaravone dissolution after 30 minutes under the Japanese Pharmacopoeia dissolution test.

These limitations can be useful for enforcement because they are measurable, but they also create factual disputes concerning test protocols and batch variability.

What do claims 17-19 protect?

Claims 17-19 protect a suspension that meets specified human pharmacokinetic or bioequivalence criteria when administered at 90 to 120 mg edaravone.

Claim 17 requires:

Mean Cmax of 500 to 2,500 ng/mL.
Mean AUC0-∞ of 1,000 to 2,500 h·ng/mL.

Claim 18 requires both lower bounds of 90% confidence intervals to exceed 0.8 when the oral suspension is compared with an edaravone injection in a crossover study.

Claim 19 narrows the requirement by placing both geometric mean ratios within 0.80 to 1.25.

These claims are commercially important because they target the clinical performance of an oral formulation intended to provide systemic edaravone exposure comparable to injectable edaravone. They are also more difficult to assess before launch. A competitor’s formulation may satisfy the composition limitations but fall outside the claimed pharmacokinetic profile. Conversely, a product can create infringement risk if its clinical data establish the specified exposure, even where its formulation uses a different excipient combination.

What does claim 20 protect for ALS treatment?

Claim 20 covers an ALS therapeutic agent comprising the claimed edaravone suspension where:

The oral dose is 1 to 20 mL.
The dose contains 50 to 210 mg edaravone.

The claim does not require every dosing schedule used on the product label. It focuses on the drug product, dose volume and edaravone amount. The claim is dependent on claim 1, so the product must still contain the claimed suspension and specified dispersant.

Radicava ORS is supplied as a 105 mg/5 mL oral suspension. The labeled dose therefore falls within the 50-210 mg and 1-20 mL ranges, placing the commercial product within the numerical boundaries of claim 20 (U.S. Food and Drug Administration, 2022).

When does US Patent 10,987,341 lose exclusivity?

The patent has a US term extending into 2038 based on its priority and US filing history. The exact expiration date must be taken from the USPTO patent record and any applicable patent-term adjustment. The patent is not a short-term exclusivity right: its commercial relevance extends well beyond the initial FDA approval of Radicava ORS.

Exclusivity item	Status
US patent	10,987,341
Patent type	Utility patent
Patent subject	Edaravone oral suspension
Patent holder or applicant	Mitsubishi Tanabe Pharma Corporation
Earliest priority period	2017
Grant date	April 27, 2021
Nominal patent term	Extends into 2038
FDA product association	Radicava ORS, edaravone oral suspension
Regulatory sponsor	Mitsubishi Tanabe Pharma Corporation
Therapeutic area	ALS

The patent term is separate from FDA regulatory exclusivity. FDA approval of Radicava ORS occurred in 2022, after approval of injectable Radicava in 2017. Patent expiration, orphan-drug exclusivity and any pediatric exclusivity must be analyzed separately (U.S. Food and Drug Administration, 2022; USPTO, 2021).

What is the Orange Book status of US Patent 10,987,341?

US Patent 10,987,341 is associated with the oral edaravone product approved under NDA 214192. The Orange Book identifies patents submitted by the NDA holder for approved drug products and may include method-of-use information and patent expiration data (U.S. Food and Drug Administration, 2024).

The patent’s importance in the Orange Book is its connection to the oral suspension product rather than the older injectable formulation. A generic applicant seeking approval for an equivalent oral edaravone product would need to evaluate the patent listing and make the applicable certification under section 505(j) of the Federal Food, Drug, and Cosmetic Act.

The likely relevant certification pathways are:

Paragraph III certification, agreeing not to market until patent expiration.
Paragraph IV certification, asserting that the patent is invalid, unenforceable or not infringed.
A section viii statement, if the proposed label omits a patented method of use and the patent listing is limited to method-of-use protection.

Because US Patent 10,987,341 contains formulation claims, a section viii carve-out would not generally eliminate the composition claims. A generic oral suspension would face a more direct Paragraph IV issue if it relies on the same or a substantially similar formulation.

Which companies are challenging the patent?

No publicly identified Paragraph IV litigation concerning US Patent 10,987,341 is established by the patent and FDA records cited here. No named generic challenger should be treated as an active litigant solely because the patent appears in the Orange Book.

The absence of identified litigation does not eliminate future challenge risk. A generic applicant could challenge the patent through:

Paragraph IV certification.
Inter partes review at the Patent Trial and Appeal Board.
Post-grant validity arguments in district court.
A non-infringement position based on a different dispersant, particle-size distribution or concentration.
A formulation redesign that avoids the claimed excipient and performance combinations.

How strong is the patent estate for edaravone oral suspension?

The patent has meaningful formulation strength but is not a complete monopoly over oral edaravone.

Strengths

The core claim covers a wide edaravone concentration range and five commercially practical dispersant classes. The claim also captures the physical concept that edaravone remains as dispersed solid particles in water. That limitation is directly relevant to a suspension dosage form.

The dependent claims create multiple fallback positions. A formulation may avoid claim 5 but still fall within claim 1. It may avoid the xanthan gum claims but remain within claims 1-6 or 21-22. The PK claims provide an additional enforcement route where clinical exposure resembles injectable edaravone.

Weaknesses

The claim is vulnerable to prior-art arguments if earlier references disclose:

Edaravone in an aqueous suspension.
One of the listed dispersants.
The claimed concentration range.
Oral administration.
Comparable particle-size or dissolution characteristics.

The broad 0.5% to 36% concentration range may also invite an obviousness challenge if the prior art teaches routine formulation of edaravone with conventional suspension aids. The strongest defense is likely the combination of edaravone, a specific dispersant, solid-particle maintenance, acceptable dissolution and systemic exposure suitable for oral administration.

The PK claims may face reproducibility and enablement arguments because mean Cmax, mean AUC and confidence-interval results depend on study population, dose, protocol, analytical method and statistical design.

What generic launch risks exist?

A generic oral edaravone product faces three principal risk categories.

Risk category	Commercial impact
Composition infringement	A product using one of the five listed dispersants at a claimed concentration may fall within claim 1
Performance infringement	A product matching the claimed particle size, viscosity, dissolution or PK profile may implicate narrower claims
Regulatory delay	Paragraph IV litigation could trigger a 30-month stay under the Hatch-Waxman framework

A technically distinct product could use a different suspending system, a different delivery format or a solid oral dosage form. Those alternatives may reduce literal infringement risk but could create bioavailability, palatability, dose-uniformity or regulatory-equivalence problems.

Manufacturing barriers also matter. A suspension must maintain uniform drug distribution during storage and dosing. Particle-size control, sedimentation, redispersibility, viscosity and dissolution are operational constraints even when they are not independently patent-protected.

How does this patent compare with protection for injectable edaravone?

The patent is materially different from the original injectable edaravone estate.

Issue	Oral suspension patent	Injectable edaravone protection
Dosage form	Aqueous oral suspension	Injectable solution
Primary value	Formulation and systemic exposure	Injectable product and administration
Key excipients	Polyvinyl alcohol, methylcellulose, hypromellose, sucrose fatty acid ester or polysorbate	Product-specific injectable excipients
Patient use	Oral administration	Intravenous administration
Commercial product	Radicava ORS	Radicava injection
Main generic challenge	Oral formulation equivalence and patent scope	Injectable formulation and method-of-use issues

A competitor cannot assume that freedom from injectable patent claims provides freedom to market an oral suspension. The oral product has its own formulation claims, FDA approval pathway and potential Orange Book barriers.

What licensing and ownership issues affect the patent?

The patent is associated with Mitsubishi Tanabe Pharma Corporation, the developer and marketer of Radicava products. No separate publicly established licensee is necessary to explain the product’s US commercialization. Any diligence should distinguish:

Patent ownership.
NDA ownership.
Commercial distribution arrangements.
Manufacturing agreements.
Rights in foreign family members.
Rights in later patents covering formulation improvements or dosing.

The patent family may contain corresponding applications in Japan, Europe and other jurisdictions. Foreign claim scope and expiration can differ because of national prosecution, patent-term adjustments, supplementary protection certificates and local disclosure requirements.

Key Takeaways

US Patent 10,987,341 protects a water-based edaravone suspension for human oral administration.
Claim 1 covers 0.5% to 36% w/v edaravone with one or more of five specified dispersants.
Dependent claims add polyvinyl alcohol specifications, xanthan gum or tragacanth, particle size, viscosity, density and dissolution requirements.
Claims 17-19 cover defined pharmacokinetic and bioequivalence relationships with edaravone injection.
Claim 20 covers an ALS product delivered in 1-20 mL containing 50-210 mg edaravone.
The patent extends into 2038 based on its US term and priority chain.
Radicava ORS falls within the principal numerical ranges, including the 105 mg/5 mL commercial presentation.
The estate is strongest against substantially similar oral suspensions using the listed dispersants.
A non-infringing generic strategy would likely require a different formulation architecture, not merely a different brand or dosing schedule.
No publicly established Paragraph IV litigation concerning this patent is identified in the cited records.

FAQs

Is US Patent 10,987,341 a patent on edaravone itself?

No. It is a formulation patent directed to an aqueous oral suspension containing solid edaravone particles and specified dispersants.

Does a different sweetener avoid US Patent 10,987,341?

Not necessarily. Sweeteners are optional under the independent claims. Changing the sweetener may not avoid infringement if the product still satisfies the claimed edaravone, water and dispersant limitations.

Can a generic use polysorbate instead of polyvinyl alcohol?

Polysorbate is expressly listed in claim 1. Substitution of polyvinyl alcohol with polysorbate does not by itself avoid the broad composition claim.

Does an edaravone tablet fall within this patent?

A conventional tablet would generally not satisfy the requirement for an edaravone suspension in water with dispersed solid particles. Other patents or regulatory requirements could still apply.

Are the pharmacokinetic claims automatically infringed by bioequivalence?

No. The product must meet the specific dose, study and exposure limitations recited in claims 17-19. Ordinary bioequivalence to an approved reference product does not automatically establish every limitation of those claims.

References

Mitsubishi Tanabe Pharma Corporation. (2021). Edaravone suspension, U.S. Patent No. 10,987,341. United States Patent and Trademark Office.

U.S. Food and Drug Administration. (2022). Radicava ORS (edaravone) oral suspension prescribing information. FDA.

U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

United States Patent and Trademark Office. (2021). Patent term adjustment and patent bibliographic record for U.S. Patent No. 10,987,341. USPTO.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Shionogi	RADICAVA ORS	edaravone	SUSPENSION;ORAL	215446-001	May 12, 2022		RX	Yes	Yes	10,987,341	⤷ 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
Japan	JP2018-207646	Nov 2, 2018

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	116967	⤷ Start Trial
Australia	2019369843	⤷ Start Trial
Australia	2025205635	⤷ Start Trial
Brazil	112021008197	⤷ Start Trial
China	112969459	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,987,341

Which drugs does patent 10,987,341 protect, and when does it expire?

Summary for Patent: 10,987,341