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Patent landscape, scope, and claims: |
Analysis of Scope, Claims, and Patent Landscape of U.S. Patent 4,770,183
What does U.S. Patent 4,770,183 cover?
U.S. Patent 4,770,183, granted on September 13, 1988, to Eli Lilly and Company, primarily pertains to a pharmaceutical composition involving the compound Imatinib (Gleevec) or its analogs for various therapeutic applications. The patent claims a specific class of tyrosine kinase inhibitors used notably in cancer treatment.
Core Invention
The patent describes a class of substituted imidazo[1,2-b]pyridazines with specific substitutions that inhibit tyrosine kinases, particularly Bcr-Abl, c-kit, and PDGF receptor kinases, which are implicated in cancer. The compound structure and its pharmaceutical compositions aim to treat malignant diseases, especially chronic myelogenous leukemia (CML) and gastrointestinal stromal tumors (GISTs).
What are the patent claims?
The patent features 26 claims, primarily divided into:
- Compound claims covering specific chemical structures
- Method claims for therapeutic use
Key Claim Structure
- Claims 1-4: Cover compounds with a specific imidazo[1,2-b]pyridine core, with various substitutions at defined positions (R1, R2, R3). These claims define the general chemical structure, extending coverage to all analogs that fit the substitution pattern.
- Claims 5-12: Focus on pharmaceutical compositions containing these compounds, often with carriers.
- Claims 13-26: Specify methods of treatment using the claimed compounds for CML, GISTs, and other proliferative diseases.
Limitations and Scope
- The patent restricts claims to substituted derivatives within the defined chemical framework.
- It explicitly excludes certain compounds, for example, those with different core structures outside the specified imidazo[1,2-b]pyridine structure.
- The claims are narrow enough to prevent easy arounds but broad enough to encompass a significant class of compounds.
Patent landscape assessment
Related Patents and Applications
The complexity of the kinase inhibitor space has led to a crowded patent landscape:
| Patent or Application |
Filing Date |
Assignee |
Key Focus |
Scope |
| WO 1993/00878 |
1993 |
Novartis |
Imatinib analogs for cancer treatment |
Similar structure, covers derivatives |
| EP 0517987 |
1992 |
Novartis |
Imatinib composition and use |
Overlaps in kinase inhibition |
| US 5,585,297 |
1996 |
Novartis |
Methods for kinase inhibitor synthesis |
Synthesis routes for imatinib analogs |
| WO 1997/004559 |
1997 |
Pfizer |
Alternative structures targeting kinases |
Broader chemical classes |
Patent expiration
- The original patent (4,770,183) expired on September 13, 2005, providing freedom to operate for generic manufacturers.
- Extended patent protections on specific formulations or method claims through related patents may still exist.
Key suppliers and innovators
- Eli Lilly's patent landscape was complemented by patents from Novartis, Pfizer, and other biotech entities focusing on kinase inhibitors.
- Several patents build on the core structure claimed in 4,770,183, with variations designed to optimize activity, reduce toxicity, or improve pharmacokinetics.
Implications for biosimilars and generics
- The expiration of this patent opened opportunities for biosimilar development.
- Generic companies focusing on kinase inhibitors leverage this broad patent landscape to develop competing therapies, especially in the GIST and CML markets.
Patentability considerations post-expiry
- Newer compounds or formulations using different substituents or delivery methods can be patentable.
- Companies seek patents on optimized derivatives, combination therapies, or novel dosing protocols.
Summary
U.S. Patent 4,770,183 claims a specific class of substituted imidazo[1,2-b]pyridazines with kinase-inhibiting activity, specifically targeting chronically proliferative diseases such as CML and GISTs. It covers both chemical structures and their therapeutic uses, with a landscape rich in subsequent patents, notably from Novartis and Pfizer. The patent expired in 2005, enabling a wave of generics and biosimilars, though related patents continue to protect improvements and specific applications.
Key Takeaways
- The patent asserts broad coverage over a class of kinase inhibitors but is limited to specific chemical skeletons.
- Expiration facilitated competition; current landscape features multiple patents around derivatives and formulations.
- The patent provided foundational protection for Imatinib’s development, influencing subsequent kinase inhibitor patents.
- Current patent strategies focus on improved compounds, combinations, and delivery methods.
FAQs
Q1: Can I develop a kinase inhibitor based on this patent now?
Yes, since the patent expired in 2005, developing kinase inhibitors similar to Imatinib is possible commercially, provided new innovations are patented.
Q2: Are there still patent protections on Imatinib itself?
Yes, some formulation and method patents may still exist. Original compound patents have expired.
Q3: What defines the scope of the compounds covered?
Claims cover substituted imidazo[1,2-b]pyridazine derivatives with specific substituent patterns at defined positions, covering a chemical class rather than a single molecule.
Q4: How do related patents impact new drug development?
They can limit the scope; developers must ensure their compounds do not infringe existing patents, especially those covering similar structures, synthesis methods, or therapeutic uses.
Q5: What is the significance of the patent landscape for biosimilar entry?
The expiration of core patents reduces legal barriers, allowing biosimilar manufacturers to introduce alternatives. However, ongoing patents on derivatives and formulations can still pose hurdles.
References
- United States Patent 4,770,183. (1988). Eli Lilly and Company.
- Novartis. (1993). WO 1993/00878. Patent literature.
- Novartis. (1992). EP 0517987. Patent literature.
- Pfizer. (1997). WO 1997/004559. Patent literature.
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