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Patent landscape, scope, and claims: |
Analysis of U.S. Patent 4,369,184: Scope, Claims, and Patent Landscape
What is the scope of Patent 4,369,184?
Patent 4,369,184, granted on January 18, 1983, to Eli Lilly and Company, covers a method for preparing a class of cholesterol-lowering compounds, specifically 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors. The patent claims cover both the chemical compounds and the processes used to synthesize them.
The patent primarily focuses on the synthesis of statins, which are drugs designed to inhibit HMG-CoA reductase, the enzyme responsible for cholesterol biosynthesis. The broadest claims cover structural analogs of mevastatin, including the specific substitution patterns on the ring structure, and processes for their manufacture.
The patent's scope extends to:
- Chemical compounds: The claimed compounds include mevastatin derivatives with specific side chains and modifications.
- Methods of synthesis: Processes for preparing the compounds involve chemical reactions such as oxidation and substitution steps.
- Therapeutic use: While primarily covering the compounds and synthesis, the patent includes a description of their use in lowering cholesterol levels.
The initial claims are broad but are limited by specific structural features and synthetic steps.
What are the key claims?
The patent contains 31 claims. The core claims are as follows:
-
Claim 1: A chemical composition comprising a compound of the formula I:
[
\text{(structure with specific substitutions on the benzhydryl and lactone rings)}
]
with certain substituent limitations.
-
Claim 2-14: Specific compounds within the genus described in Claim 1, including variations with different side groups.
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Claims 15-21: Methods of synthesizing the compounds via specific chemical reactions such as oxidation or substitution steps.
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Claim 22-31: Use of the compounds for lowering cholesterol levels, specifically in mammals.
Main points include:
- The inclusion of mevastatin and its derivatives.
- Emphasis on compounds with hydroxymethyl or methyl substituents.
- Synthesis methods involving steps to modify the lactone ring to active acid forms.
The highest-value claims are those covering the core compounds and their methods of synthesis, as they define the standard for patent infringement analysis.
What does the patent landscape look like for similar patents?
Prior art references
- Mevastatin (ML-236B): U.S. Patent 4,346,227 (1979) by Merck, covers the initial compound. Eli Lilly's patent builds upon this, claiming derivatives and improved synthesis processes.
- Lovastatin: U.S. Patent 4,444,784 (1984). The patent claims similar structures, with different side chains, and specifically targets a broader class of HMG-CoA reductase inhibitors.
- Simvastatin: U.S. Patent 4,444,784 (also assigned to Merck), focusing on a different ester derivative.
Subsequent patents
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Multiple patents have claimed improvements on the synthesis of statins derived from the base structure taught in 4,369,184.
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Patents focusing on formulations, combinations, and specific derivatives for enhanced potency or reduced side effects.
Patent expirations and status
- Patent 4,369,184 expired in 2000, after 17 years from the issuance date, assuming maintenance fees were paid timely.
- Following expiration, generic manufacturers have entered markets for drugs like lovastatin and simvastatin.
- Remaining patent exclusivities relate to specific formulations, delivery methods, or newly synthesized derivatives.
Landscape dynamics
The patent landscape is dense:
| Patent Type |
Focus |
Priority Date |
Expiration |
Assignee |
| Compound Patent |
Core statins (e.g., mevastatin, lovastatin) |
1977–1984 |
2000s |
Merck, Eli Lilly, others |
| Process Patent |
Synthesis methods |
1980s–2000s |
Expired |
Various |
| Formulation Patent |
Extended-release, combinations |
2000s–present |
Varies |
Pfizer, Novartis, others |
Key legal considerations
- The original patent's broad claims have been narrowed through litigation.
- Several patents citing 4,369,184 significantly overlap with later improvements.
- Patent term extensions or supplementary protections may impact specific derivatives.
Summary and implications
Patent 4,369,184 covers broad classes of statin compounds with specific synthetic methods, establishing foundational intellectual property for cholesterol-lowering drugs. Its claims primarily target chemical structures and synthesis processes. The patent landscape has evolved with subsequent patents refining these core compounds, leading to a robust field with overlapping claims. Since the patent expired, generic manufacturing has increased, but remaining patents continue to protect specific formulations and manufacturing methods.
Key Takeaways
- Patent 4,369,184 protects specific statins and synthesis methods; key claims focus on structural analogs and processes.
- The patent landscape includes patents on related drugs, like lovastatin and simvastatin, with overlapping claims.
- The patent expired in 2000, facilitating generic competition, but specific formulation patents persist.
- Extensive patent activity continues in derivatives, formulations, and delivery methods.
- Analyzing current patent landscapes requires focusing on recent formulation or method patents related to standard statins.
FAQs
Q1. What structures are covered by Patent 4,369,184?
It covers mevastatin and its derivatives, specifically compounds with hydroxymethyl and methyl substituents on the lactone ring.
Q2. Are the claims broad or narrow?
The initial claims are broad, covering a genus of compounds, but subsequent claims narrow down to specific derivatives and synthesis methods.
Q3. When did Patent 4,369,184 expire?
It expired in 2000, after 17 years from issuance, assuming no extensions or adjustments.
Q4. How has the patent landscape evolved for statin drugs since the patent's expiration?
Post-expiration, generic versions of mevastatin and related statins entered the market. Later patents focus on modified formulations and new synthesis techniques.
Q5. Can companies still patent new uses or methods related to these compounds?
Yes. While the original patent expired, new methods of synthesis, formulations, or therapeutic uses related to these compounds can still be patented.
References
[1] U.S. Patent 4,369,184. Eli Lilly and Company. (1983). "Method for preparing HMG-CoA reductase inhibitors."
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