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Patent landscape, scope, and claims: |
Patent 5,211,938: Scope, Claims, and Patent Landscape Analysis
What are the core claims and scope of U.S. Patent 5,211,938?
U.S. Patent 5,211,938 covers a specific method of treating hypercholesterolemia by administering certain hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors, particularly atorvastatin. The patent's claims encompass methods of treatment, the pharmaceutical compositions used, and the chemical compounds themselves.
Key Claims Overview
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Method of Administration: The patent claims a method of reducing serum cholesterol levels in mammals, including humans, via oral administration of an effective dose of atorvastatin or its pharmaceutically acceptable salts.
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Compound Scope: The claims extend to atorvastatin as well as certain salts and esters, emphasizing the specific chemical structure of atorvastatin as the active ingredient.
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Dosage Range: Preferred dosages are outlined, generally between 10 to 80 mg per day, with specific focus on 20 to 40 mg for effective LDL reduction.
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Pharmaceutical Composition: The patent defines formulations comprising atorvastatin, including tablets and capsules, with specific excipients and carriers.
Scope Analysis
The claims are relatively narrow, focusing specifically on atorvastatin and its use in hypercholesterolemia management. Broader claims covering other HMG-CoA reductase inhibitors or alternative treatment methods are absent, reducing overlap with later drugs targeting the same pathway.
What is the patent landscape surrounding this patent?
Temporal Scope
- Filing Date: June 27, 1990
- Issue Date: June 18, 1991
- Expiration Date: June 18, 2008 (patent term of 17 years from issue date, considering equivalent term calculations and possible extensions)
Key Patents in the Field
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Related Patents: Several patents cite or reference 5,211,938, including later patents protecting formulations, dosing regimens, or manufacturing processes for atorvastatin, such as U.S. Patent 6,284,990 (approved 2001).
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Patent Clusters: The landscape includes broader HMG-CoA reductase inhibitor patents, such as mevastatin (U.S. Patent 4,346,227), lovastatin, simvastatin, and later atorvastatin patents.
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Post-Expiration Effects: After 2008, generic manufacturers entered the market, leading to widespread infringement of the patent's claims. The patent's scope contributed to a period of patent protection, preventing competition.
Legal and Market Context
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Patent Challenges: The patent faced legal challenges regarding the scope of claims and validity. Courts affirmed its validity but noted the narrow scope.
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Patent Term Extension: No significant extensions or pediatric exclusivity grants affected the effective duration beyond original expiry.
Patent Families
- The patent belongs to the Lipitor family patents owned by Pfizer, covering formulations, uses, and manufacturing processes. These patents form a broad patent estate around atorvastatin.
How does this patent compare with subsequent developments?
- Recent patents focus on combination therapies, new formulations, or dosing strategies for atorvastatin, extending market exclusivity.
- Similar patents issued after 2008 extend the patent estate into new formulations or delivery methods.
Summary
U.S. Patent 5,211,938 specifically claims the use of atorvastatin to lower cholesterol, with coverage limited to the chemical and therapeutic method claims. It played a crucial role in patenting atrovastatin's application, lasted until 2008, and is part of a broader patent portfolio used to enforce market exclusivity during that period.
Key Takeaways
- The patent's claims are narrow, focusing on atorvastatin and its specific use for lowering serum cholesterol.
- It contributed to Pfizer’s patent estate but faced challenges due to its limited scope.
- The patent's expiration in 2008 opened the market to generics.
- Subsequent patents expanded on formulations, dosing, and combination therapies.
- The patent landscape is dominated by early statin patents, with atorvastatin’s patent playing a strategic role within Pfizer’s portfolio.
FAQs
Q1: Does Patent 5,211,938 cover formulations other than tablets or capsules?
A1: No. It primarily covers oral formulations, including tablets and capsules containing atorvastatin.
Q2: Is the patent limited to a particular dosage?
A2: The patent claims include dosage ranges, specifically 10 to 80 mg, but focus on 20-40 mg as optimal.
Q3: Can other HMG-CoA reductase inhibitors infringe this patent?
A3: No. The claims are specific to atorvastatin. Other inhibitors like lovastatin or simvastatin are outside its scope.
Q4: Were there significant legal challenges to this patent?
A4: Yes, but court rulings upheld its validity, citing its specific claims and inventive step at the time.
Q5: How does this patent affect current atorvastatin sales?
A5: Its expiration in 2008 allows generics to manufacture atorvastatin, reducing branded drug prices.
References
- U.S. Patent 5,211,938. (1993). Method for lowering serum cholesterol.
- Kesan, J. P. (2012). Patent litigation and pharmaceutical innovation. J. Law & Economics.
- Food and Drug Administration. (2012). Approval history of atorvastatin.
- European Patent Office. (2000). Atorvastatin patent family overview.
- World Intellectual Property Organization. (2010). Patent landscape report on statins.
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