Understanding the Scope and Claims of United States Patent 8,795,725: A Detailed Analysis
Introduction to Horizant and Patent 8,795,725
Horizant, marketed by Azurity, is a brand name for the drug gabapentin enacarbil, an extended-release oral formulation used primarily for treating restless legs syndrome and postherpetic neuralgia. One of the key patents protecting this drug is United States Patent 8,795,725, which focuses on the sustained release oral dosage forms of a gabapentin prodrug.
Patent Overview
Patent Number and Title:
- US8795725: "GABA analog prodrug sustained release oral dosage forms"
Issuance and Expiration Dates:
- Issued: August 5, 2014
- Expires: June 10, 2029[2][4].
Inventors and Assignees
The patent was invented by Kenneth C. Cundy, Srikonda Sastry, Manshiu Leung, Balaji V. Kadri, and Paul E. Stach, and is assigned to XenoPort, Inc.[2].
Claims and Scope
Sustained Release Oral Dosage Forms
The patent describes sustained release oral dosage forms of a gabapentin prodrug, specifically 1-{[(α-isobutanoyloxyethoxy)carbonyl]aminomethyl}-1-cyclohexane acetic acid. These dosage forms are designed to release the active ingredient over an extended period, enhancing the therapeutic efficacy and patient compliance.
Composition and Uses
The patent covers the compositions and methods of preparing these sustained release oral dosage forms. It includes details on the formulation, which involves the use of rate-controlling polymers to achieve the desired release profile. These formulations are useful for treating or preventing diseases and disorders for which gabapentin is therapeutically effective, such as restless legs syndrome and postherpetic neuralgia[2][5].
Patent Claims
The patent claims are broad and cover several aspects of the drug formulation:
- Claim 1: A sustained release oral dosage form comprising a gabapentin prodrug and at least one rate-controlling polymer.
- Claim 2: The dosage form of claim 1, wherein the gabapentin prodrug is 1-{[(α-isobutanoyloxyethoxy)carbonyl]aminomethyl}-1-cyclohexane acetic acid.
- Claim 3: The dosage form of claim 1 or 2, wherein the rate-controlling polymer is selected from the group consisting of hydroxypropyl methylcellulose, hydroxyethyl cellulose, and polyvinyl acetate.
These claims ensure that any generic version of Horizant must avoid infringing on these specific formulations and methods of preparation[2].
Regulatory Exclusivities
In addition to patent protection, Horizant has been granted several regulatory exclusivities by the FDA. These exclusivities, which can run simultaneously with patent protection, prevent other companies from marketing a generic or bioequivalent version of Horizant until these exclusivities expire. The combination of patent and regulatory exclusivities significantly delays the entry of generic versions into the market[1][2].
Impact on Generic Entry
The expiration of Patent 8,795,725 on June 10, 2029, marks the earliest date when generic versions of Horizant could potentially enter the market, assuming no other patent or regulatory barriers remain. However, this date can be influenced by various factors such as patent challenges, generic licensing agreements, or changes in regulatory exclusivities[2][4].
Economic and Market Implications
The protection offered by this patent and others like it is crucial for maintaining the market exclusivity of Horizant. The annual sales of Horizant were $171 million in 2021, with peak sales reaching $535 million in 2018. This significant revenue underscores the economic importance of these patents in delaying generic competition[4].
Legal Activities and Patent Maintenance
The life of a patent can be affected by various legal activities such as the payment of maintenance fees, patent challenges, and amendments to claims. For Patent 8,795,725, recent activities include the payment of maintenance fees, which are essential for keeping the patent active. Any changes in these activities can impact the patent's expiration date and, consequently, the timing of generic entry[1].
Conclusion
United States Patent 8,795,725 is a critical component of the patent landscape protecting Horizant. It covers the sustained release oral dosage forms of a gabapentin prodrug, ensuring that the drug maintains its market exclusivity until June 10, 2029. Understanding the scope and claims of this patent is essential for pharmaceutical companies, regulatory bodies, and healthcare providers to navigate the complex landscape of drug development and generic entry.
Key Takeaways
- Patent Number and Title: US8795725 - "GABA analog prodrug sustained release oral dosage forms"
- Expiration Date: June 10, 2029
- Inventors and Assignees: Kenneth C. Cundy et al., assigned to XenoPort, Inc.
- Claims: Cover sustained release oral dosage forms of a gabapentin prodrug
- Regulatory Exclusivities: Delay generic entry beyond patent expiration
- Impact on Generic Entry: Earliest generic entry date is June 10, 2029, subject to changes
- Economic Implications: Significant revenue protection for Horizant
FAQs
Q1: What is the main focus of United States Patent 8,795,725?
- The patent focuses on sustained release oral dosage forms of a gabapentin prodrug.
Q2: Who are the inventors and assignees of this patent?
- The inventors are Kenneth C. Cundy, Srikonda Sastry, Manshiu Leung, Balaji V. Kadri, and Paul E. Stach, and it is assigned to XenoPort, Inc.
Q3: When does this patent expire?
- The patent expires on June 10, 2029.
Q4: What regulatory exclusivities affect the generic entry of Horizant?
- FDA-granted exclusivities, in addition to patent protection, delay the entry of generic versions.
Q5: How does this patent impact the market for Horizant?
- It maintains market exclusivity for Horizant until the patent expires, protecting significant revenue for the brand.
Sources
- Pharsight: Horizant patent expiration.
- Drugs.com: Generic Horizant Availability.
- Hoover Institution: Patent Claims and Patent Scope.
- DrugPatentWatch: When will the patents on HORIZANT expire, and ...
- Unified Patents Portal: WO-2003103634-A1.
