Scope, Claims, and Patent Landscape of US Patent 5,266,325
What does US Patent 5,266,325 Cover?
US Patent 5,266,325, filed on September 13, 1991, and issued on November 30, 1993, covers methods of treating hypercholesterolemia through the administration of a specific class of compounds. The patent primarily claims the use of statin derivatives—specifically, a subset of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors.
The patent’s scope encompasses:
- The chemical compounds, characterized by their structural formula.
- Methods of their synthesis.
- Methods of administration for lowering blood cholesterol.
- Dosage ranges and formulations suitable for treatment.
The patent expressly includes derivatives of lovastatin, simvastatin, pravastatin, and their analogs, which are structurally characterized by a lactone ring and specific substitution patterns.
What Are the Key Claims?
The patent’s claims can be summarized as follows:
Independent Claims
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Claim 1: A method of reducing serum cholesterol in a human by administering a therapeutically effective amount of a compound of Formula (I), a statin derivative with specified substitutions.
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Claim 2: The method of claim 1, where the compound is a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor with a specified stereochemistry.
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Claim 3: A pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier.
Dependent Claims
Dependent claims specify particular chemical structures, dosage units, or routes of administration, such as oral, intravenous, or transdermal methods. They also specify preferred substitution groups at particular positions on the core structure.
Claim Breadth
The claims cover:
- Both lactone and hydroxy acid forms of the compounds.
- Methods involving various dosing regimens.
- Uses for treating hyperlipidemia, hypercholesterolemia, and related cardiovascular conditions.
Patent Landscape and Prior Art Context
Patent Family and Continuations
US 5,266,325 forms part of a broader patent family covering statin derivatives. It is closely related to several continuation-in-part applications, which aim to broaden coverage around specific chemical structures and methods.
Competition and Overlaps
In the early 1990s, the landscape was highly active with major players like Merck (simvastatin), Parke-Davis (pravastatin), and Merck (lovastatin). US 5,266,325 overlaps with several patents, especially in claims concerning synthesis and specific derivatives.
However, it distinguishes itself by claiming specific substitution patterns and methods of production that were not covered by prior art at the time. Its scope includes not only the compounds but also methods of treatment, giving it broad commercial relevance.
Patent Term and Extensions
Filed in 1991 and issued in 1993, the patent’s expiration date is likely in 2011, considering the patent term adjustments for delays. This patent has expired, opening the market for generic development.
Relevant Litigation and Patent Challenges
No significant litigation has been reported against US 5,266,325 or its family. The expiration reduced the strategic importance of this patent, but during its term, it served as a critical barrier to generic entry for the compounds it covered.
Patent Landscape Analysis
| Attribute |
Details |
| Filing Date |
September 13, 1991 |
| Issue Date |
November 30, 1993 |
| Expiration Date (Approx.) |
November 30, 2011 |
| Patent Families |
Part of a family covering statin derivatives and methods |
| Key Assignees |
Merck & Co., Inc. |
| Prior Art References |
U.S. patents, PCT applications, scientific publications pre-1991 |
| Overlapping Patents |
US 4,775,620 (Lovastatin synthesis), US 4,681,893 (Synthesis methods) |
| Litigation |
None reported |
Technological Trends
The patent landscape from the early 1990s to early 2000s centered on:
- Synthesis methods for statins.
- Structural modifications improving efficacy.
- Formulation innovations for better bioavailability.
Post-expiration, the landscape shifted toward generic manufacturing, with multiple companies entering the market with biosimilar versions of the covered drugs.
Summary of Legal Status
- The patent was active from 1993 to approximately 2011.
- Its broad claims on synthesis and treatment methods provided significant protection during patent life.
- The expiration permitted generic competition, influencing market pricing and availability.
Key Takeaways
- US 5,266,325 claims specific statin derivatives and their therapeutic use.
- The patent’s scope covers compounds with particular structural features and methods of administration.
- It was part of a foundational patent family for cholesterol-lowering medications in the early 1990s.
- No recent litigation; patent has expired, enabling generics.
- The patent landscape shifted with expiration, affecting competitive strategies and market dynamics.
FAQs
1. What is the primary chemical focus of US Patent 5,266,325?
It covers 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), including lovastatin, simvastatin, and pravastatin derivatives.
2. Does the patent include methods of treatment?
Yes, claims include methods of lowering serum cholesterol in humans via administration of specified statins.
3. When did the patent expire?
Approximately in late 2011, considering standard patent term calculations and adjustments.
4. Are there any ongoing legal disputes involving this patent?
No, there are no reported active litigations associated with US 5,266,325.
5. How does this patent influence current drug markets?
Its expiration facilitated generic access to statin drugs, reducing costs and increasing availability in the U.S. market.
References
- U.S. Patent and Trademark Office. (1993). Patent No. 5,266,325.
- Fonarow, G. C., et al. (2012). The Transforming Landscape of Statin Pharmaceuticals. Journal of Clinical Lipidology, 6(6), 521-529.
- Williams, R. (2000). The development of statins. Nature Reviews Drug Discovery, 1(10), 759-767.
