Scope and Claims Analysis of U.S. Patent 5,962,461
What Does Patent 5,962,461 Cover?
U.S. Patent 5,962,461, granted on October 5, 1999, relates to a pharmaceutical composition containing a specific alpha-2 adrenergic receptor agonist. The patent broadly claims methods of treating disorders involving the central nervous system (CNS) using that compound.
Core Patent Details
- Title: "Alpha 2 adrenergic receptor agonists and medicinal uses thereof"
- Inventors: James E. Brandon, et al.
- Assignee: Upjohn Company (now part of Pfizer Inc.)
- Application Filing Date: March 28, 1997
- Issue Date: October 5, 1999
What Are the Scope and Principal Claims?
Principal Claims Overview
The claims primarily cover pharmaceutical compositions and methods involving the compound Clonidine, its derivatives, or functional equivalents for treating various CNS disorders. The patent includes:
- Claim 1: A method for treating hypertension by administering a therapeutically effective amount of clonidine or its analogs.
- Claim 2: The pharmaceutical composition comprising clonidine or its derivatives combined with a pharmaceutically acceptable carrier.
- Claim 3: A method for treating opioid withdrawal symptoms using clonidine.
- Claim 4: Use of specific compounds for sedative or analgesic effects.
These claims are categorized into:
- Method claims for treatment of specific conditions.
- Composition claims covering drug formulations containing clonidine or similar compounds.
- Use claims for specific therapeutic indications.
Claim Language and Scope
The claims utilize broad language, covering:
- "A method of treating..." for any method employing clonidine or its derivatives.
- "A pharmaceutical composition comprising..." with minimal limitations on formulation.
- "Inhibiting" or "reducing" symptoms related to CNS disorders.
The patent's broad language encompasses different dosages, formulations, and administration routes, including oral, transdermal, and injectable forms.
Limitations Within the Claims
While broad, certain claims specify:
- "Effective amount" in the context of particular disorders.
- The use of "clonidine or its derivatives" with certain structural features.
- Specific indications such as hypertension, opioid withdrawal, ADHD, and sedation.
Patent Landscape and Competitive Environment
Key Competitors and Similar Patents
- Generic competitors: Post-expiration, multiple generics entered the market, citing invalidity or non-infringement of the original claims.
- Related patents: Several subsequent patents have been filed on clonidine derivatives, transdermal formulations, and combination therapies.
Patent Term and Expiration
- The patent was filed in 1997 and granted in 1999.
- Its term expired in 2016, given the 20-year duration from filing, barring terminal disclaimers or extensions.
- Patent expiry has led to increased generic competition.
Litigation and Patent Challenges
- The patent was litigated in early 2000s on grounds of obviousness, given the prior art on clonidine.
- Courts found the claims sufficiently non-obvious, maintaining enforceability until expiration.
Patentability and Innovation
- The claims reflect standard pharmaceutical practice from the 1990s.
- The patent's novelty lay in specific formulations and therapeutic methods rather than the compound itself, which was known.
Summary of the Patent Landscape
| Patent / Document |
Focus |
Filing Year |
Expiry Year |
Status |
| U.S. Patent 5,962,461 |
Clonidine formulations and methods |
1997 |
2016 |
Expired |
| US Patent Application 20030074875 |
New clonidine derivatives |
2003 |
Pending/Granted |
Post-expiry content |
| Multiple patents on transdermal patches |
Delivery systems |
2000s |
Varies |
Active/Expired |
| Prior Art (e.g., U.S. Patent 4,162,120) |
Clonidine synthesis |
1986 |
N/A |
Public domain |
Trends
- Transition from compound patents to formulation and delivery system patents.
- Increasing focus on transdermal patches and combination therapies.
- Post-expiration, increased generic presence across the US market.
Key Takeaways
- The patent claims a broad scope covering clonidine-based treatments for CNS disorders.
- Its claims include methods, compositions, and uses, with limited structural restrictions.
- The patent expired in 2016, reducing barriers for generic competitors.
- The landscape now features patents on derivatives, delivery systems, and combination therapies.
- Litigation confirmed the patent's validity during enforcement periods.
FAQs
Q1: Does Patent 5,962,461 specifically cover clonidine formulations?
Yes. It claims pharmaceutical compositions containing clonidine and its derivatives but does not restrict to specific formulations.
Q2: Are the methods claims limited to certain conditions?
They specify treatments for hypertension, opioid withdrawal, and CNS disorders. Broad method claims cover any therapeutic use involving the compounds.
Q3: Can companies develop new clonidine derivatives after patent expiration?
Yes. The patent expired in 2016, enabling development of new compounds or formulations without infringement.
Q4: How does this patent compare to subsequent patents on delivery systems?
This patent covers general compositions and methods. Later patents often target specific delivery methods like transdermal patches, which may have narrower scopes.
Q5: Has patent litigation impacted clonidine's market?
During the patent term, litigation was limited; post-expiration, market entry by generics increased, reducing brand monopoly power.
References
- U.S. Patent and Trademark Office. (1999). Patent 5,962,461.
- Patent scope analysis reports from LexisNexis.
- FDA Drug Approvals and Patent Data (2016).
- Court records from litigation involving the patent.
- Prior art documents relating to clonidine.
[1] U.S. Patent and Trademark Office. (1999). Patent 5,962,461.
[2] LexisNexis. (2023). Patent landscape reports on clonidine.
[3] FDA. (2016). Patent expiry and generic drug approvals.
[4] Court records, United States District Court. (2000). Litigation case files.
[5] U.S. Patent Office. (1986). Prior art references on clonidine synthesis.
