US Patent 9,867,792: Amantadine Extended-Release Patent Scope, Expiration, and Generic Risk
US Patent 9,867,792 protects a specific once-daily bedtime administration regimen for extended-release amantadine. The patent does not broadly claim every amantadine formulation or every treatment of Parkinson’s disease. Its enforceable scope depends on the combination of dose, timing, extended-release performance, dissolution profile, and pharmacokinetic exposure.
The patent is commercially relevant to Gocovri, an extended-release amantadine product developed by Adamas Pharmaceuticals and now marketed by Supernus Pharmaceuticals. The patent’s nominal 20-year term is tied to its earliest effective nonprovisional priority date and is subject to patent-term adjustment, terminal disclaimers, and any patent-term extension. Based on the patent family chronology, the basic term runs into 2031, but the precise expiration date should be determined from the USPTO term calculation and any Orange Book listing.
What does US Patent 9,867,792 claim?
The independent claim is a method-of-treatment claim with multiple cumulative limitations. A potentially infringing product and use must satisfy each material limitation of claim 1.
| Claim element |
Scope |
| Active drug |
Amantadine or a pharmaceutically acceptable salt |
| Patient |
Human patient in need of treatment |
| Route |
Oral administration |
| Frequency |
Once daily |
| Administration timing |
Zero to four hours before bedtime |
| Dose |
220 mg to 455 mg of amantadine drug |
| Release type |
Extended-release dosage form |
| Dissolution at two hours |
Not more than 25% released |
| Dissolution at 12 hours |
At least 80% released |
| Dissolution test |
USP Apparatus II, 50 rpm, 500 mL water, 37°C |
| Pharmacokinetics |
Single-dose, fasted, healthy-subject study with amantadine Tmax of 8 to 20 hours |
The claim is narrower than a conventional formulation claim because it requires a method of administering the product. A composition that meets the dissolution and pharmacokinetic characteristics does not, by itself, necessarily infringe claim 1 unless it is administered in the claimed manner.
The claim also uses both product-performance and clinical-use limitations. The dissolution limitations are laboratory-based. The Tmax limitation depends on a human pharmacokinetic study and may require analysis of the product under the specified single-dose, fasted conditions.
How do dependent claims 2 through 19 narrow the patent?
The dependent claims create narrower fall-back positions around pharmacokinetics, dissolution, capsule configuration, and dose strength.
| Claims |
Added limitation |
| 2 |
Tmax of 9 to 18 hours |
| 3 |
Tmax of 11 to 18 hours |
| 4 |
No more than 10% release at one hour |
| 5 |
40% to 80% release at six hours |
| 6 |
Claims 4 and 5 combined |
| 7 |
25% to 55% release at six hours |
| 8 |
Claims 4 and 7 combined |
| 9 |
30% to 50% release at four hours |
| 10 |
Claims 4 and 9 combined |
| 11 |
Claims 5 and 9 combined |
| 12 |
One, two, three, or four unit dosage forms |
| 13 |
One, two, or three capsules containing coated pellets |
| 14 |
One, two, or three capsules |
| 15 |
One 340 mg unit or two 170 mg units |
| 16 |
Claim 15 using an amantadine salt |
| 17 |
Claim 15 using amantadine hydrochloride |
| 18 |
Amantadine salt |
| 19 |
Amantadine hydrochloride |
Claims 15 through 17 are commercially important because they focus on the 340 mg total dose associated with Gocovri’s marketed strength. Claim 17 is particularly narrow, covering a 340 mg total dose administered as one unit or two 170 mg units where the drug is amantadine hydrochloride.
What formulations are protected by US Patent 9,867,792?
The patent protects extended-release amantadine formulations that satisfy the stated in vitro release and human Tmax parameters. Claim 13 expressly identifies capsules containing coated pellets, but the independent claim does not require pellets. Other technologies could fall within claim 1 if they meet the same release and pharmacokinetic limitations.
The claim therefore has a performance-based formulation scope:
- The formulation must delay release during the initial period.
- It must release at least 80% by 12 hours under the specified test conditions.
- It must produce a delayed amantadine Tmax in the claimed range.
- It must be dosed once daily within four hours before bedtime.
A formulation that uses a different polymer, coating, matrix system, multiparticulate structure, or capsule shell may still infringe if it meets all claimed functional parameters. Conversely, a technically similar formulation may avoid literal infringement if it falls outside a required numerical range.
When does US Patent 9,867,792 lose exclusivity?
The patent issued on January 9, 2018. Its earliest effective priority date appears to be in 2011, placing the ordinary patent term in 2031. The exact expiration date cannot be reduced to the issue date plus 20 years. The calculation depends on the earliest effective filing date, patent-term adjustment, any terminal disclaimer, and possible patent-term extension.
| Event |
Date or period |
| Earliest family priority |
2011 family date |
| Patent issued |
January 9, 2018 |
| Nominal term endpoint |
2031, subject to USPTO adjustment |
| Product associated with the estate |
Gocovri extended-release amantadine |
| FDA approval of Gocovri |
August 24, 2017 |
| Statutory exclusivity |
Small-molecule regulatory exclusivity, separate from patent term |
FDA approval of Gocovri did not create new chemical entity exclusivity because amantadine had been previously approved. The approval could support three-year exclusivity for the new clinical investigations underlying the approved product and indications, but that regulatory exclusivity is distinct from the patent and does not extend the patent term.[2]
What is the Orange Book status of US Patent 9,867,792?
US Patent 9,867,792 is associated with the Gocovri patent estate and is relevant to FDA-listed patent analysis for the product. Orange Book listing status is product-specific. A patent may be listed for a particular strength, dosage form, or method of use, and the listing does not mean that every claim in the patent covers every generic amantadine product.
For an ANDA applicant, an Orange Book-listed patent can trigger one of four certifications:
- Paragraph I: no patent information is listed.
- Paragraph II: the listed patent has expired.
- Paragraph III: the applicant will wait until patent expiration.
- Paragraph IV: the patent is invalid, unenforceable, or will not be infringed.
A Paragraph IV notice to the NDA holder and patent owner can initiate a 45-day period for filing an infringement action under the Hatch-Waxman framework. A timely suit generally creates a 30-month stay of ANDA approval, subject to statutory exceptions and court action.[3]
Which companies are challenging Gocovri patents?
The claim text identifies no Paragraph IV challenger, litigation defendant, settlement, or licensee. A current challenger list cannot be derived from US Patent 9,867,792 alone. The relevant public sources are FDA’s current Orange Book, ANDA litigation filings, PACER, and the patent owner’s SEC disclosures.
The principal commercial exposure is Supernus, which acquired Adamas Pharmaceuticals in 2021. Supernus obtained Gocovri and the associated intellectual-property portfolio through that transaction.[4] Any generic entrant would likely evaluate the full Gocovri patent estate rather than this patent in isolation.
How strong is the patent estate for Gocovri?
US Patent 9,867,792 has meaningful but circumscribed strength.
Strengths
- It combines dosing time, dose amount, extended release, dissolution, and Tmax.
- Claims 15 through 17 target the commercially important 340 mg regimen.
- The bedtime-use limitation aligns with Gocovri’s labeled administration.
- The pharmacokinetic limitation may capture products designed to reproduce the same delayed exposure.
- The dissolution limitations provide objective testing criteria.
Vulnerabilities
- Every limitation must be met for literal infringement.
- The claim is vulnerable to a product with a different dose, administration window, release profile, or Tmax.
- Tmax is a variable human pharmacokinetic parameter and may raise reproducibility and claim-construction issues.
- The claim requires a particular dissolution protocol, including medium volume, temperature, apparatus, and rotation speed.
- The patent does not claim all amantadine products, all extended-release products, or all treatment methods for Parkinson’s disease.
- The patent does not expressly claim a specific polymer, coating chemistry, manufacturing process, or pellet architecture in claim 1.
The patent is strongest against an ANDA product intentionally designed to match Gocovri’s dose, delayed-release profile, bedtime administration, and pharmacokinetics. It is weaker against a product that uses a materially different regimen and does not meet the claimed numerical ranges.
What generic launch scenarios exist?
Launch after patent expiration
A generic applicant may defer approval until the patent and any other blocking patents expire. This is the lowest litigation-risk pathway but delays market entry.
Paragraph III certification
A Paragraph III certification acknowledges the patent and commits the applicant to launching after expiration. This approach avoids a patent challenge but typically prevents an earlier launch.
Paragraph IV challenge
A Paragraph IV applicant may argue that the patent is invalid, unenforceable, or not infringed. The principal noninfringement theories would involve:
- Administration outside the zero-to-four-hour bedtime window.
- A total dose below 220 mg or above 455 mg.
- Immediate-release or a release profile outside the claimed ranges.
- Tmax outside the applicable range.
- A product not used according to the proposed label.
Invalidity theories could target anticipation, obviousness, written description, enablement, indefiniteness, or lack of subject-matter eligibility. The strongest technical disputes would likely concern whether the claimed combination of dissolution profile, bedtime dosing, and delayed Tmax was adequately supported and nonobvious at the relevant priority date.
At-risk launch
An applicant may launch before final resolution of patent litigation. This creates potential damages exposure, an injunction risk, and possible enhanced damages if willful infringement is established. The commercial value of this strategy depends on the size of the Gocovri market, the number of remaining patents, and the probability that at least one patent blocks approval or launch.
Does US Patent 9,867,792 create biosimilar risk?
No. Amantadine is a chemically synthesized small molecule, not a biologic. The relevant competitive pathway is an ANDA generic, not a biosimilar application under the Public Health Service Act.
The principal regulatory and IP issues are therefore Orange Book listing, Paragraph IV certification, 30-month stays, product labeling, formulation design, and method-of-use infringement. A generic applicant does not need to reproduce Gocovri’s manufacturing process if it can demonstrate pharmaceutical equivalence, bioequivalence, and regulatory compliance through the ANDA pathway.
What manufacturing and geographic barriers remain?
The patent has US territorial effect. It does not directly block manufacture, sale, or use outside the United States, although foreign counterpart patents may create parallel restrictions.
Manufacturing risk is concentrated in the ability to produce an extended-release amantadine dosage form with consistent dissolution and bioequivalence. Coated-pellet systems can create scale-up, coating uniformity, dose-content uniformity, and stability challenges. Those technical issues may be commercially significant even where the resulting product is designed to avoid the patent claims.
The patent’s method format also creates label-based risk. A generic label that instructs once-daily bedtime administration could provide evidence supporting induced infringement if the product meets the formulation and pharmacokinetic limitations.
How does this patent compare with ordinary formulation patents?
| Patent characteristic |
US 9,867,792 |
| Claim category |
Method of treatment |
| Active ingredient |
Amantadine or salt |
| Core protection |
Dose, timing, release, dissolution, and Tmax combination |
| Manufacturing claim |
Not present in the supplied claims |
| Composition claim |
Not present in the supplied claims |
| Product-specific strength |
Strongest at 340 mg total dose |
| Generic risk |
Highest for label-matched extended-release products |
| Biosimilar relevance |
None |
| Geographic scope |
United States only |
| Commercial product link |
Gocovri |
The patent should be analyzed with all other Orange Book-listed Gocovri patents. A generic applicant may avoid this patent but still face separate patents covering formulation architecture, dosing methods, treatment indications, or other product attributes.
Key Takeaways
- US Patent 9,867,792 is a combination method patent for once-daily bedtime administration of extended-release amantadine.
- Claim 1 requires all of the following: 220 mg to 455 mg, oral dosing, administration zero to four hours before bedtime, extended release, specified dissolution results, and amantadine Tmax of 8 to 20 hours.
- Claims 15 through 17 focus on the commercially important 340 mg amantadine hydrochloride regimen.
- The patent does not broadly cover every amantadine formulation or every Parkinson’s disease treatment.
- Gocovri is the principal commercial product associated with the patent estate.
- Generic risk is greatest for an ANDA product that matches Gocovri’s dose, label, bedtime regimen, dissolution profile, and pharmacokinetic exposure.
- Amantadine creates generic, not biosimilar, competition.
- The ordinary patent term reaches into 2031, subject to the USPTO’s final term calculation and any applicable adjustments.
- The full commercial risk requires review of the entire Orange Book-listed Gocovri portfolio, not this patent alone.
FAQs
Is US Patent 9,867,792 a composition patent?
No. The supplied claims are method-of-administration claims. They protect use of a qualifying extended-release amantadine product under specified dose, timing, dissolution, and Tmax conditions.
Does a 340 mg amantadine product automatically infringe the patent?
No. A 340 mg product must also satisfy the extended-release, bedtime-administration, dissolution, and Tmax limitations. Claims 15 through 17 narrow the dose and salt but do not eliminate the other inherited limitations from claim 1.
Can a generic avoid the patent by using two capsules instead of one?
Not necessarily. Claims 12 through 14 expressly cover specified numbers of unit dosage forms and capsules. A two-capsule presentation may still fall within the claims if the other limitations are met.
Does a different release-control polymer avoid infringement?
Not automatically. The independent claim is primarily performance-based. A different polymer or coating may still infringe if the resulting product and use meet the claimed dissolution and Tmax requirements.
What is the main litigation issue for an ANDA filer?
The central issue is likely whether the proposed product and labeled use meet every limitation, particularly the dissolution ranges, bedtime dosing window, and human Tmax requirement. Invalidity challenges would likely focus on obviousness and the support for the claimed pharmacokinetic and dissolution combination.
References
- United States Patent and Trademark Office. (2018). US Patent No. 9,867,792, methods of administering amantadine extended-release pharmaceutical compositions.
- U.S. Food and Drug Administration. (2017). Gocovri prescribing information. Adamas Pharmaceuticals, Inc.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book.
- Supernus Pharmaceuticals, Inc. (2021). Current report on Form 8-K: Acquisition of Adamas Pharmaceuticals, Inc. U.S. Securities and Exchange Commission.
