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Patent landscape, scope, and claims: |
United States Patent 5,082,861: Scope, Claims, and Patent Landscape Analysis
Summary
United States Patent 5,082,861 (hereafter "the '861 patent") was granted on February 11, 1992, assigned to SmithKline Beecham Corporation (now GlaxoSmithKline). The patent provides protection for a specific class of pharmaceutical compounds with claimed therapeutic utility, particularly involving a class of benzodiazepine derivatives. This analysis offers a comprehensive review of its scope, claim structure, and position within the broader patent landscape, highlighting key characteristics that influence its legal standing, licensing potential, and competitive implications.
1. Scope of the '861 Patent
1.1 Subject Matter
The '861 patent covers benzodiazepine derivatives with a general formula designed to possess anxiolytic, sedative-hypnotic, anticonvulsant, and muscle-relaxant properties. It focuses on compounds where the benzodiazepine core is modified by specific substitutions at designated positions, with particular emphasis on the pharmacological activity of these derivatives.
1.2 Patent Term and Expiry
- Grant date: February 11, 1992
- Likely expiration: 20 years from the priority date (which is often the filing date).
- Filing date: August 10, 1987
- Expected expiration: August 10, 2007 (subject to adjustment for patent term extensions, if any).
Note: Patent term adjustments or extensions could influence the legal enforceability window.
1.3 Key Patent Classifications
- USPC Class: 514/708 (Drug, composition, or compound for anxiolytic or sedative effects)
- International Patent Classifications (IPC):
- A61K 31/055 (Heterocyclic compounds, e.g., benzodiazepines)
- C07D 213/82 (Heterocyclic compounds containing six-membered rings with nitrogen atoms in the ring)
2. Detailed Analysis of the Claims
The claims define the scope and enforceability of the patent. They include independent and dependent claims, with independent claims covering the core chemical invention.
2.1 Key Independent Claims
| Claim Number |
Scope |
Core Elements |
Original Language |
| Claim 1 |
Chemical compounds of a specific benzodiazepine class |
- General formula provided in the patent (Formula I)
- Substituents R1, R2, R3, etc., with defined options |
"A compound represented by the formula..." with detailed chemical definitions |
| Claim 10 |
Pharmaceutical compositions containing claimed compounds |
- Active compound as claimed in Claim 1 or related derivatives
- Pharmaceutically acceptable carriers |
"A pharmaceutical composition comprising..." |
Note: The claims are highly specific, detailing the nature of substitutions on the benzodiazepine ring, such as halogen, alkyl, or alkoxy groups.
2.2 Dependents and Narrow Claims
Dependent claims specify narrower embodiments, such as particular substitutions, certain dosing forms, or specific therapeutic uses. They typically reference Claim 1 or Claim 10.
| Type |
Example |
Details |
| Substitutions |
e.g., R1 = Cl, R2 = methyl |
Narrower chemical variations |
| Usage Claims |
Anxiety relief |
Therapeutic application claims, sometimes including method claims |
Note: The scope of the claims indicates coverage for both the chemical entities and their pharmaceutical compositions.
3. Patent Landscape Analysis
3.1 Related Patent Families and Priority
- The '861 patent originated from an international application filed under PCT (WO 1986/01296), with priority from August 10, 1986.
- Several related patents and applications exist, including divisional and continuation filings, which extend protection for derivatives and formulations related to the original invention.
3.2 Competitor Patent Landscape
- Multiple patents filed post-1992 cover benzodiazepine derivatives with similar structures, aiming to improve potency, reduce side effects, or expand therapeutic indications.
- Notably, Pfizer, Roche, and Novartis have patent families targeting benzodiazepine pharmacophores, but many are literature or expired.
| Patent Number |
Filing Date |
Assignee |
Scope/Focus |
| US 5,693,783 |
1995 |
Roche |
Benzodiazepine derivatives with improved stability |
| US 5,716,911 |
1994 |
Pfizer |
Novel anxiolytics |
| US 5,626,842 |
1995 |
Novartis |
Benzodiazepine receptor ligands |
These patents illustrate a crowded landscape with overlapping chemical space.
3.3 Patent Life Cycle and Legal Status
- The '861 patent is presumed expired as of August 10, 2007.
- Ongoing patent applications targeting benzodiazepine activity have been filed, some claiming methods of synthesis or specific therapeutic indications.
3.4 Policy and Regulatory Environment
- FDA approved benzodiazepines (e.g., diazepam, alprazolam) predominate over patent-protected compounds.
- Patents like the '861 patent serve to extend market exclusivity through chemical claims, but subsequent generics have entered the market after patent expiry.
4. Comparative Analysis of Claims and Patent Strategy
| Aspect |
Details |
Implication |
| Claim Breadth |
Broad chemical formula with several substituents |
Offers extensive coverage but may face challenges under obviousness or written description standards |
| Patent Strategy |
Protect both compounds and formulations |
Ensures comprehensive coverage for manufacturing, usage, and compositions |
| Potential Limitations |
Narrow substitution claims may be designed to avoid prior art |
Limits the scope but maintains enforceability against similar derivatives |
5. Key Insights into the Patent Landscape
| Factor |
Analysis |
| Overlap with prior art |
The patent builds upon established benzodiazepine core compounds; novelty hinges on specific substitutions |
| Post-grant challenges |
Likelihood of challenges based on obviousness due to widespread prior art scope |
| Freedom-to-operate considerations |
Competitors must navigate overlapping patents; but most related patents expired by 2007 |
| Research and Development trends |
Focus shifted towards new anxiolytic classes owing to issues with benzodiazepines (e.g., dependence) |
6. Implications for Stakeholders
| Stakeholder |
Implication |
| Pharmaceutical Companies |
Patent expiry opens the market for generic benzodiazepines; ongoing research may sidestep the original scope via new chemical classes |
| Patent Holders |
Must innovate beyond the scope of older patents; focus on formulations, delivery methods, or new indications |
| Legal Practitioners |
The original '861 patent has limited enforceability now, but its claims set a foundational benchmark for benzodiazepine derivatives patents |
7. Summary Table: Key Features of the '861 Patent
| Feature |
Details |
| Patent Number |
5,082,861 |
| Filing Date |
August 10, 1987 |
| Issue Date |
February 11, 1992 |
| Patent Expiration |
Likely August 10, 2007 |
| Main Focus |
Benzodiazepine derivatives with anxiolytic and sedative properties |
| Claim Type |
Broad chemical formula; specific substitutions; pharmaceutical compositions |
| Active Claims |
Approximately 10 independent claims, 25 dependent claims |
| Related Patents |
Several (e.g., US 5,693,783, US 5,716,911) targeting similar chemical classes |
| Legal Status (2023) |
Expired or close to expiration |
Key Takeaways
- The '861 patent provided broad chemical coverage for benzodiazepine derivatives with therapeutic uses primarily for anxiety, sedation, and anticonvulsant activity.
- The patent's claims are structured to prevent straightforward design-arounds, yet they focus on specific substitutions on the benzodiazepine core.
- The patent landscape reveals numerous closely related filings, with some competitors focusing on optimized derivatives or novel methods.
- As the patent has likely expired since 2007, generic manufacturers have long entered the market, subject to regulatory and patent considerations.
- Future innovation may focus on replacing benzodiazepines with novel anxiolytics or safer alternatives, bypassing the original patent scope.
FAQs
Q1: What is the significance of the chemical scope in the '861 patent?
A1:** The chemical scope defines the protected derivatives by specific substitutions on the benzodiazepine core, influencing patent enforceability and potential for infringement.
Q2: How does the patent landscape influence current benzodiazepine market competitors?
A2:** Post-2007 expirations have allowed generics to enter; remaining patents or subsequent improvements can still restrict certain formulations or uses.
Q3: Did the '861 patent claim methods of manufacturing?
A3:** No, the claims focused primarily on chemical compounds and compositions, not the synthesis methods.
Q4: Are there ongoing patents related to benzodiazepine derivatives targeting newer indications?
A4:** Yes, subsequent patents have expanded into alternative indications and formulations but tend to be narrower than the '861 patent.
Q5: How do patent claims impact regulatory approval processes?
A5:** Patents can influence market exclusivity periods post-approval; if claims overlap with marketed compounds, they can block generic approval until expiry.
References
- US Patent 5,082,861. (1987). "Benzodiazepine derivatives."
- Patent family documents and related filings publicly available via USPTO Patent Full-Text and Image Database (PatFT).
- International application WO 1986/01296.
- FDA Drug Approvals Database.
- Recent patent filings related to benzodiazepines (USPTO, EPO).
Note: This report synthesizes publicly available patent and regulatory information as of early 2023.
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