US Patent 8,227,484: Scope, Claims, Expiration and Patent Landscape for Dextromethorphan-Quinidine

US Patent No. 8,227,484 protects specified methods of treating pseudobulbar affect and emotional lability with dextromethorphan plus quinidine. Its central limitation is a daily dextromethorphan-to-quinidine weight ratio of 1:0.75 or less of quinidine, with dextromethorphan dosed at approximately 20-60 mg/day and quinidine at approximately 10-30 mg/day. The claims cover the principal Nuedexta dosing configurations, including 40 mg/20 mg and 60 mg/20 mg daily regimens.

The patent is a method-of-treatment patent. It does not, based on the supplied claims, independently claim the chemical combination as a composition, a tablet formulation, a manufacturing process, or a pharmaceutical package.

What does US Patent 8,227,484 protect?

The patent protects administering dextromethorphan and quinidine to a patient with pseudobulbar affect or emotional lability within defined dose and ratio parameters.

Claim element	Scope
Disease or condition	Pseudobulbar affect or emotional lability
Active ingredients	Dextromethorphan combined with quinidine
Dextromethorphan dose	About 20-60 mg/day
Quinidine dose	About 10-30 mg/day
Ratio	Dextromethorphan-to-quinidine ratio of 1:0.75 or less of quinidine
Administration	One combined daily dose, at least two combined doses, or separate doses
Disease causes	Neurodegenerative disease, neurodegenerative condition, or brain injury
Salt forms	Pharmaceutically acceptable salts, including hydrobromide and sulfate forms
Specific regimens	40 mg/20 mg and 60 mg/20 mg daily combinations

The practical commercial target is a product that administers approximately 20 mg of dextromethorphan hydrobromide and 10 mg of quinidine sulfate twice per day. That regimen corresponds to approximately 40 mg/day of dextromethorphan and 20 mg/day of quinidine and is expressly covered by claims 15 and 17.

How does the independent claim define infringement risk?

Claim 1 requires all of the following:

A patient in need of treatment.
Pseudobulbar affect or emotional lability.
Administration of both dextromethorphan and quinidine.
Dextromethorphan at approximately 20-60 mg/day.
Quinidine at approximately 10-30 mg/day.
A dextromethorphan-to-quinidine weight ratio of 1:0.75 or less of quinidine.

The ratio is a material limitation. A 20 mg/day dextromethorphan and 20 mg/day quinidine regimen has a 1:1 ratio and would not literally satisfy the stated 1:0.75-or-less limitation. By contrast:

Dextromethorphan	Quinidine	Ratio	Relationship to claim 1
20 mg/day	10 mg/day	1:0.50	Within ratio
40 mg/day	20 mg/day	1:0.50	Within ratio
60 mg/day	20 mg/day	1:0.33	Within ratio
60 mg/day	30 mg/day	1:0.50	Within ratio
20 mg/day	20 mg/day	1:1.00	Outside stated ratio
40 mg/day	30 mg/day	1:0.75	At the stated boundary
60 mg/day	30 mg/day	1:0.50	Within ratio

The use of “about” creates a factual claim-construction issue. Courts generally assess the term in light of the specification, prosecution history, technical context and whether the accused dose falls within a clinically and commercially meaningful tolerance. The ratio also raises a mass-basis issue where dextromethorphan hydrobromide and quinidine sulfate are used rather than the free bases.

What do claims 2 through 17 add?

Disease etiology and patient population

Claim 2 narrows claim 1 to pseudobulbar affect or emotional lability caused by a neurodegenerative disease, neurodegenerative condition or brain injury. It may encompass conditions such as amyotrophic lateral sclerosis, multiple sclerosis, stroke-related injury or other central nervous system disorders, subject to claim construction and the patent specification.

The claim is broader in wording than the original FDA-approved Nuedexta indication, which was pseudobulbar affect in patients with amyotrophic lateral sclerosis or multiple sclerosis. FDA labeling therefore does not define the full scope of claim 2. It does, however, provide important evidence regarding the clinical use and dosing of the product.[2]

Dosing frequency

Claims 3 and 4 cover combined dosing:

Claim 3: one combined dose per day.
Claim 4: at least two combined doses per day.

Claim 11 separately covers administration of dextromethorphan and quinidine in separate doses. This distinction may matter for a product supplied as a fixed-dose combination tablet versus a regimen involving separately administered products.

A generic product using the same active ingredients in a different tablet configuration may still face method-of-use risk if its labeling instructs patients to administer both ingredients within the claimed ranges.

Salt forms

Claims 7 and 8 cover pharmaceutically acceptable salt forms. Claim 8 identifies salts of free acids, inorganic salts, sulfates, hydrochlorides and hydrobromides.

Claims 9, 10, 13, 16 and 17 are particularly relevant to Nuedexta-type products:

About 20 mg/day quinidine sulfate.
About 60 mg/day dextromethorphan hydrobromide.
About 40 mg/day dextromethorphan hydrobromide.
About 60 mg/day dextromethorphan with about 20 mg/day quinidine.
About 40 mg/day dextromethorphan with about 20 mg/day quinidine.
About 60 mg/day dextromethorphan hydrobromide with about 20 mg/day quinidine sulfate.
About 40 mg/day dextromethorphan hydrobromide with about 20 mg/day quinidine sulfate.

These claims reduce the design-around value of changing from free-base ingredients to the salt forms used in the commercial product.

What formulations are protected by US 8,227,484?

The supplied claims do not require a particular dosage form. They can reach administration of the two active ingredients as:

A single combined tablet or capsule.
Multiple combined tablets or capsules per day.
Separate dextromethorphan and quinidine products.
Products containing dextromethorphan hydrobromide.
Products containing quinidine sulfate.
Other pharmaceutically acceptable salt forms within the claim language.

The claims do not expressly require:

Immediate release.
Extended release.
A specific tablet weight.
A particular excipient.
A particular dissolution profile.
A specific particle size.
A specific manufacturing process.
A particular packaging configuration.

That distinction is significant. A competitor may avoid a separate formulation patent while still practicing the method claims through its prescribing information, dosage instructions or actual administration pattern.

How does the patent compare with composition and formulation patents?

US 8,227,484 should be analyzed as one layer of a broader Nuedexta patent estate.

Patent category	Typical protected subject matter	Relevance to generic entry
Method-of-treatment patent	Treating pseudobulbar affect with specified doses and ratios	Creates labeling and inducement risk
Composition patent	Dextromethorphan-quinidine combination	Can reach the product itself
Formulation patent	Tablet structure, release profile or excipient system	Can block a particular dosage form
Method-of-use patent	Treatment of a defined disease or patient group	May support FDA use-code enforcement
Manufacturing patent	Production, blending, compression or coating process	Usually less central to ANDA product launch
Regulatory listing	FDA Orange Book patent and use-code information	Determines notice and Paragraph IV procedure

A freedom-to-operate review must therefore distinguish the claims of US 8,227,484 from other patents listed for Nuedexta. The supplied claim set alone does not establish whether other composition or formulation patents remain enforceable.

What is the FDA and Orange Book status of the protected product?

Nuedexta is the principal commercial product associated with the claimed dextromethorphan-quinidine regimen. The FDA approved Nuedexta under NDA 021879 for the treatment of pseudobulbar affect.[2] The labeled starting regimen is generally one capsule daily for seven days, followed by one capsule twice daily, subject to the prescribing information.

The commercial 20 mg dextromethorphan hydrobromide/10 mg quinidine sulfate capsule therefore produces a daily maintenance dose of approximately 40 mg dextromethorphan and 20 mg quinidine. That regimen maps directly to claims 15 and 17.

The Orange Book, rather than the patent grant alone, determines whether US 8,227,484 is listed against the approved NDA and whether an ANDA applicant must address it through a certification.[3] A listed method-of-use patent may be addressed through a Paragraph IV certification or, where appropriate, a section viii statement carving out the patented use. The commercial impact depends on the scope of the listed use code and the wording of the generic label.

When does US 8,227,484 lose exclusivity?

The patent’s exact expiration date cannot be derived from the claims or grant number alone. The controlling term depends on:

The effective nonprovisional filing date.
Any patent-term adjustment.
Any patent-term extension.
Terminal disclaimers.
Whether the patent is a continuation or divisional.
Any applicable pediatric exclusivity.

For a US utility patent, the ordinary term is generally 20 years from the earliest effective nonprovisional filing date, subject to statutory adjustments.[4] US 8,227,484 was granted on July 24, 2012. The grant date does not establish the expiration date.

The commercial exclusivity analysis must separately account for FDA regulatory exclusivity. Nuedexta’s original approval in 2010 is distinct from patent protection. Small-molecule products are generally subject to five-year new chemical entity exclusivity, three-year clinical-investigation exclusivity for certain supplemental approvals, and possible orphan-drug exclusivity where applicable. Those periods do not automatically extend every patent claim.

What Paragraph IV challenges and generic entry risks exist?

A generic applicant seeking approval of dextromethorphan hydrobromide/quinidine sulfate may need to address listed patents through one or more of the following:

Paragraph I certification: no patent information has been filed.
Paragraph II certification: the patent has expired.
Paragraph III certification: the applicant will wait until patent expiration.
Paragraph IV certification: the patent is invalid, unenforceable or not infringed.
Section viii statement: the applicant will omit a patented method of use.

US 8,227,484 presents a meaningful Paragraph IV risk because the approved Nuedexta maintenance regimen appears directly within the claims. A generic applicant may pursue several defenses:

The patent is invalid for anticipation or obviousness.
The dose and ratio limitations lack adequate written description or enablement.
The proposed label does not instruct the claimed method.
The accused product does not satisfy the ratio when salt weights are calculated correctly.
The claim’s “about” ranges are indefinite or do not cover the proposed regimen.
The patent is expired, terminally disclaimed or otherwise unenforceable.

The strongest practical design-around would require avoiding the claimed dosing ranges, ratio, disease indication or labeling instructions. That strategy may reduce patent exposure but can also remove the product from the principal FDA-approved use and commercial market.

The claim set does not establish the identity of any current Paragraph IV challenger, the filing date of any ANDA, or the existence of a litigation settlement. Those facts must be taken from FDA Orange Book records, ANDA litigation complaints and docket entries.

Which companies control the commercial patent position?

Avanir Pharmaceuticals developed Nuedexta and was acquired by Otsuka Pharmaceutical in a transaction announced in 2014 and completed in 2015.[5] Otsuka became the principal commercial sponsor and patent-estate holder associated with Nuedexta.

The relevant commercial actors are:

Company	Role
Avanir Pharmaceuticals	Original developer and sponsor
Otsuka Pharmaceutical	Parent company and commercial rights holder following acquisition
Otsuka America Pharmaceutical	US commercial and regulatory operations
Potential ANDA applicants	Generic manufacturers seeking approval and challenging listed patents

Licensing arrangements, patent assignments and security interests should be confirmed through USPTO assignment records. A patent’s named assignee at grant is not necessarily its current legal owner.

How strong is the patent estate for Nuedexta?

US 8,227,484 has meaningful commercial strength because it covers the clinically central maintenance regimen rather than an unusual or impractical dose. Claims 15 and 17 are especially important because they recite approximately 40 mg or 60 mg of dextromethorphan with 20 mg of quinidine, matching the principal product dosing architecture.

Its limitations are equally important:

It is a method patent, not necessarily a product-composition patent.
Infringement may depend on physician instructions, patient administration and generic labeling.
The ratio must be calculated on the legally relevant weight basis.
Claims directed to “about” numerical amounts can generate claim-construction disputes.
A generic may attempt a section viii carve-out or label modification.
Patent expiration and Orange Book listing status control the timing of litigation exposure.

The estate is stronger against a generic that copies the approved indication and dosing instructions than against a product marketed for unrelated uses with no instruction to treat pseudobulbar affect.

Does biosimilar risk apply to dextromethorphan-quinidine?

No. Dextromethorphan and quinidine are small-molecule active ingredients. A competing product would generally use the ANDA pathway for a generic drug, not the biosimilar pathway under the Biologics Price Competition and Innovation Act.

The principal regulatory risk is therefore generic substitution, Paragraph IV litigation and possible section viii labeling. Biosimilar interchangeability, reference-product exclusivity under the biologics statute and patent dance procedures are not the applicable framework.

What manufacturing and intellectual-property barriers remain?

The claims supplied do not impose a manufacturing-process limitation. A competitor could potentially use a different:

Tablet press.
Granulation process.
Excipient system.
Coating process.
Supplier.
Packaging configuration.
Manufacturing site.

That change would not avoid the method claims if the finished product is administered within the claimed dose and ratio ranges for the claimed indication.

Manufacturing patents, formulation patents and process know-how may create separate barriers. Those barriers must be evaluated independently from US 8,227,484.

Key Takeaways

US 8,227,484 is a method-of-treatment patent for dextromethorphan plus quinidine in pseudobulbar affect or emotional lability.
Claim 1 requires approximately 20-60 mg/day dextromethorphan, 10-30 mg/day quinidine and a ratio no greater than 1:0.75 quinidine by weight.
Claims 15 and 17 directly cover approximately 40 mg/day dextromethorphan plus 20 mg/day quinidine, the core Nuedexta maintenance regimen.
Claims 7-10 and 13-17 specifically address dextromethorphan hydrobromide and quinidine sulfate.
The patent covers administration methods, not necessarily the tablet composition, formulation technology or manufacturing process.
Generic risk is highest where an ANDA label copies the approved pseudobulbar-affect indication and twice-daily dosing.
Exact patent expiration, Orange Book listing, Paragraph IV challenges and litigation settlements cannot be established from the claims alone.
Nuedexta was developed by Avanir and commercialized under Otsuka following Otsuka’s acquisition of Avanir.

FAQs

Is a 40 mg dextromethorphan and 20 mg quinidine regimen covered?

Yes. Claims 15 and 17 expressly recite approximately 40 mg of dextromethorphan and approximately 20 mg of quinidine per day, including the hydrobromide and sulfate forms.

Does a 20 mg dextromethorphan and 20 mg quinidine regimen fall within claim 1?

On its face, no. That regimen has a 1:1 weight ratio, while claim 1 requires a dextromethorphan-to-quinidine ratio of 1:0.75 or less of quinidine.

Can separate dextromethorphan and quinidine products infringe?

Yes. Claim 11 expressly covers administration in separate doses. The absence of a fixed-dose combination tablet does not by itself avoid the claim.

Does a generic need to challenge every Nuedexta patent?

An ANDA applicant must address each relevant Orange Book-listed patent, usually through a Paragraph I, II, III or IV certification or a section viii statement for a patented method of use. The required certification depends on the listing and the proposed label.

Is Nuedexta protected by biosimilar exclusivity?

No. Nuedexta is a small-molecule drug. Generic-drug rules, including ANDA and Paragraph IV procedures, apply rather than biosimilar approval rules.

References

United States Patent and Trademark Office. (2012). U.S. Patent No. 8,227,484, Methods for treating pseudobulbar affect.
U.S. Food and Drug Administration. (2023). Nuedexta prescribing information. Otsuka America Pharmaceutical, Inc.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book.
35 U.S.C. §§ 154, 156, 271, 355.
Otsuka Pharmaceutical Co., Ltd. (2014). Otsuka Pharmaceutical to acquire Avanir Pharmaceuticals. Corporate press release.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1539166	⤷ Start Trial	C300626	Netherlands	⤷ Start Trial
European Patent Office	1539166	⤷ Start Trial	CR 2013 00059	Denmark	⤷ Start Trial
European Patent Office	1539166	⤷ Start Trial	CA 2013 00059	Denmark	⤷ Start Trial
European Patent Office	1539166	⤷ Start Trial	C20130030 00105	Estonia	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,227,484

Summary for Patent: 8,227,484