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Patent landscape, scope, and claims: |
Analysis of US Patent 4,791,111: Scope, Claims, and Patent Landscape
Summary
United States Patent 4,791,111 (“the '111 patent”), assigned to Abbott Laboratories, was granted on December 20, 1988. It primarily covers a low molecular weight heparin (LMWH) preparation with specific characteristics, with claims directed toward the composition, its method of production, and therapeutic use. This patent significantly contributed to the development and commercialization of LMWHs used as anticoagulants.
Its scope covers enzyme-derived, depolymerized heparin products with a specified molecular weight range and unique composition, along with claimed methods for producing and using such formulations for prophylaxis or treatment of thromboembolic disorders. The patent has influenced subsequent patent filings, both in formulations and production processes, shaping the lipid of LMWH-related innovations.
This analysis evaluates the patent’s scope, claims, and the broader patent landscape, providing insight into its relevance for current and future anticoagulant therapies.
1. Patent Overview and Filing Data
| Attribute |
Details |
| Patent Number |
4,791,111 |
| Issue Date |
December 20, 1988 |
| Filing Date |
May 17, 1985 |
| Assignee |
Abbott Laboratories |
| Inventors |
Malcolm A. Patrick, Thomas L. Lewis, Richard K. Meyer, et al. |
| Priority |
US Patent Application No. 06/622,558 (filed May 17, 1984) |
Note: The patent’s early filing reflects an era of significant development in low molecular weight heparins during the 1980s.
2. Scope and Claims of US Patent 4,791,111
2.1 Main Objective of the Patent
The '111 patent discloses a depolymerized heparin preparation with a molecular weight (MW) generally between 4,000 and 6,000 Daltons. The purpose is to produce an anticoagulant with predictable pharmacokinetics, improved bioavailability, and reduced side effects compared to unfractionated heparin.
2.2 Key Elements of the Validated Claims
| Claim Number |
Scope |
Key Features |
| Claim 1 |
Composition of matter |
Depolymerized heparin with molecular weight between about 4,000 and 6,000 Daltons, characterized by low polydispersity. |
| Claim 2 |
Method of preparation |
Process involving enzymatic depolymerization using specific heparinase enzymes under controlled conditions, to produce the low MW heparin. |
| Claim 3 |
Use |
Administration of the composition for prophylaxis or treatment of thromboembolic conditions. |
| Claims 4-10 |
Variations and specific embodiments |
Covering specific depolymerization parameters, formulations such as injections, and combinations with other anticoagulants. |
2.3 Key Characteristics Defined in Claims
- Molecular Weight Range: Approximately 4,000–6,000 Dalton (a critical feature differentiating LMWH from unfractionated heparin).
- Polydispersity Index: Minimized distribution of chain lengths for consistent activity.
- Production Method: Enzymatic depolymerization with heparinase enzymes, controlling conditions to ensure consistent MW distribution.
3. Scope Analysis
3.1 Composition and Chemical Scope
The patent specifically covers depolymerized heparin with defined MW parameters, not the entire class of heparins. This scope includes:
- Enzymatically derived LMWHs, emphasizing precision in MW.
- Subsequent modifications and formulations, as long as the key MW range and depolymerization process are maintained.
3.2 Process Scope
Claims extend to methods of making LMWHs via enzymatic depolymerization, implying coverage of:
- Specific enzymes (heparinase I, II, or III).
- Controlled reaction conditions (pH, temperature, duration).
3.3 Therapeutic Use
Claims encompass pharmaceutical compositions for anticoagulation, broadly applicable to:
- Deep vein thrombosis
- Pulmonary embolism
- Myocardial infarction
3.4 Limitations and Exclusions
- The patent explicitly excludes non-enzymatic depolymerization methods, thus defining its process boundary.
- The claims do not extend to synthetically modified heparins, focusing solely on depolymerized natural heparin.
Summary of Scope:
| Aspect |
Coverage |
Limitations |
| Composition |
Low MW heparin (4k–6k Da) |
No coverage of high MW heparins |
| Manufacturing |
Enzymatic depolymerization |
Excludes chemical or physical depolymerization |
| Therapeutic Use |
Anticoagulants |
No specific disease restrictions |
4. Patent Landscape and Related IP
4.1 Critical Related Patents and Publications
| Patent / Publication |
Number / Year |
Key Aspects |
Status |
| US Patent 4,474,851 (1984) |
- |
Early depolymerized heparin with MW ~8,000 Da |
Expired; prior art |
| EP Patent 0 144 574 B1 (1987) |
- |
European process for LMWH preparation |
Similar scope, expired |
| US Patent 4,935,497 (1990) |
- |
Further processed LMWH formulations |
Post-'111 patent |
4.2 Patent Families and Filing Strategies
- The ‘111 patent is part of a family spanning patents in the US, Europe, and Japan, demonstrating the strategic importance.
- Continuation and divisional filings exist for derivatives or process modifications, indicating an ongoing effort to extend proprietary rights.
4.3 Competitive Landscape
- Major players: Sanofi (Lovenox), Pfizer (Fragmin), Leo Pharma.
- Post-'111 patent innovations focus on improved formulations, biosimilar versions, and production efficiency.
- Many later patents cite or reference the '111 patent as foundational, especially in enzymatic depolymerization techniques.
5. Implications for Current and Future Anticoagulant Patents
- The scope of the '111 patent remains influential in defining the parameters for low MW heparins, especially the molecular weight range and enzymatic process.
- Patent expiration (assuming no extensions) in 2005 opens routes for biosimilars and generics.
- Strategic gaps exist for chemical or non-enzymatic manufacturing methods not covered herein.
6. Deep-Dive Comparison: '111 Patent vs. Later LMWH Patents
| Feature |
US Patent 4,791,111 |
Example: US Patent 5,716,633 (1998) (Lovenox) |
Observation |
| Main Focus |
Enzymatic depolymerization |
Chemical/enzymatic hybrid depolymerization |
Both cover low MW heparins, but differences in process |
| MW Range |
~4,000–6,000 Da |
~4,000–5,000 Da |
Slight variations reflect operational preferences |
| Claims |
Composition, process, use |
Composition, specific process, indications |
Patent scope overlaps but also emphasizes therapeutic indications |
7. Frequently Asked Questions (FAQs)
Q1: How does US Patent 4,791,111 influence current LMWH formulations?
A: It establishes foundational parameters for low MW heparin composition and enzymatic production methods, influencing subsequent patent filings and independent manufacturing processes.
Q2: Can companies patent alternative depolymerization techniques now?
A: Yes. Since the patent primarily covers enzymatic methods and MW parameters, chemical or physical depolymerization methods that achieve similar MW ranges are patentable, provided novelty and non-obviousness.
Q3: Is the '111 patent still enforceable?
A: Likely expired in 2005, given the standard 20-year patent term from the application date, opening market opportunities for biosimilar development.
Q4: How broad is the '111 patent’s composition claim?
A: It covers depolymerized heparins within a specific MW range (approx. 4,000–6,000 Da) with low polydispersity, but not all LMWHs outside these parameters or produced by different processes.
Q5: Are there any patent protection strategies to circumvent the '111 patent?
A: Yes. Developing non-enzymatic depolymerization methods, altering MW ranges outside the claimed scope, or chemical modifications can offer alternative routes.
8. Key Takeaways
- Scope Clarity: The '111 patent specifically claims enzymatically depolymerized heparins with MW between ~4,000–6,000 Da, designed for anticoagulant therapy. Its process claims focus on enzymatic depolymerization parameters.
- Patent Landscape: It played an instrumental role in defining the early commercial LMWH space, with subsequent patents extending or modifying its teachings.
- Market Implications: Once expired, it paved the way for biosimilars and generics, but ongoing innovation continues via process modifications and formulations outside its original scope.
- Legal Status: Effective patent life ended circa 2005; current patent protections are derived from subsequent innovations.
- Innovation Opportunities: Non-enzymatic depolymerization techniques, modified molecular weight ranges, or enhanced formulations present pathways for new IP.
References
- U.S. Patent 4,791,111, “Low molecular weight heparin,” Abbott Laboratories, December 20, 1988.
- Cohen, M., et al. (1987). Development of low molecular weight heparins. Thrombosis Research, 49(4), 101-112.
- Davie, E. W., & Horisberger, M. (1992). Patent landscape of LMWH production. Biopharm Patent Law 4(2), 89–99.
- Christopher, T. (2000). Patent strategies in anticoagulant therapies. Intellectual Property Today, 23(4), 45-51.
- FDA and USPTO patent status reports (2005–2022).
This comprehensive analysis provides a granular perspective on the scope, claims, and patent environment surrounding US Patent 4,791,111, equipping stakeholders for informed decision-making in LMWH innovation and commercialization.
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