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Patent landscape, scope, and claims: |
Overview of U.S. Patent 5,869,100: Scope, Claims, and Patent Landscape
U.S. Patent 5,869,100 (issued February 2, 1999) covers a pharmaceutical composition designed for targeted drug delivery, specifically involving a ligand, a drug, and a carrier. The patent primarily focuses on enhancing drug specificity and reducing side effects through receptor-mediated delivery systems.
Scope of Patent 5,869,100
The patent claims cover a composition comprising:
- A ligand that binds selectively to a receptor on target cells.
- A therapeutic or diagnostic agent attached to the ligand.
- A carrier molecule facilitating delivery.
These components form a conjugate designed to improve the localization of active agents to specific cell types, thereby increasing efficacy and limiting off-target effects.
Key aspects of the scope include:
- Structures of conjugates linking ligands to drugs via specific linker groups.
- Methods of synthesizing the conjugates.
- Use of the conjugates in treating or diagnosing diseases involving particular cell receptor profiles, notably in cancer and infectious diseases.
The scope does not extend to unlinked mixtures or non-specific conjugates. It emphasizes receptor-specific targeting, especially involving ligands that bind to cellular receptors overexpressed in disease states.
Claims Breakdown
Independent Claims
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A composition comprising:
- A ligand specific for a receptor on a cell surface,
- A therapeutic or diagnostic agent,
- A carrier linking the ligand and agent.
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The composition of claim 1, where the ligand is an antibody fragment, a peptide, or a hormone.
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The composition of claim 1 or 2, where the linker is a carbamate, hydrazone, or ester bond.
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The method of delivering a therapeutic agent to a target cell expressing a receptor, involving administering the conjugate described.
Dependent Claims
- Specify particular ligand types (e.g., folate, transferrin, epidermal growth factor).
- Use specific linkers, such as cleavable hydrazone bonds.
- Focus on particular diseases, including various cancers and infections.
- Describe methods of synthesis, storage, and administration.
The breadth of claims emphasizes both the conjugate compositions and their methods of use, with some claims narrowing to specific ligand/receptor pairs.
Patent Landscape Analysis
Related Patents and Fields
The patent landscape includes prior art involving:
- Antibody-drug conjugates for cancer therapy (e.g., Pfizer’s Mylotarg, 5,532,211).
- Ligand-targeted delivery systems involving folate or transferrin (e.g., U.S. Patent 5,442,052).
- Cleavable linkers facilitating controlled drug release (e.g., U.S. Patent 5,859,205).
The '100 patent is situated within the active field of receptor-targeted therapies, commonly aimed at oncology and infectious disease treatments. It overlaps with patents on conjugates that attach drugs to ligands for cellular targeting, often emphasizing cleavable linkers for controlled release.
Patent Filing and Priority
Filed on August 21, 1996, with priority claims from an earlier provisional application. Its filing date positions it in the late 1990s surge of targeted drug delivery systems development.
Patent Term and Expiry
Expected expiration around August 21, 2016, absent terminal disclaimers or extension filings. As of the current date (2023), the patent has expired, freeing the technology for generic development and further research.
Patent Citations and Influences
The '100 patent has been cited in subsequent patents related to:
- Novel conjugates for targeted delivery,
- Cleavable linkers with improved stability,
- Ligand modifications for enhanced receptor affinity.
Citations reflect foundational status within receptor-mediated drug targeting and conjugate chemistry, influencing both academia and industry.
Implications for Development and Commercialization
The patent's expiration allows free use of its concepts, but ongoing research has shifted focus toward next-generation linkers and multi-valent conjugates with improved pharmacokinetics. Major pharmaceutical companies have developed products based on similar principles, notably antibody-drug conjugates (ADCs), which embody the same core idea of receptor-specific targeting.
Potential competitive advantages hinge on whether new formulations retain the specific ligand, linker stability, or target receptors outlined in the '100 patent.
Summary Table
| Aspect |
Details |
| Patent Number |
5,869,100 |
| Issue Date |
February 2, 1999 |
| Expiration Date |
Approximately August 21, 2016 |
| Technology Focus |
Ligand-drug conjugates for receptor-mediated targeting |
| Receptor Types |
Cell surface receptors (e.g., folate, transferrin, EGF) |
| Linker Types |
Carbamate, hydrazone, ester |
| Diseases Targeted |
Cancer, infectious diseases |
| Influencing Patents |
5,532,211; 5,442,052; 5,859,205 |
Key Takeaways
- The patent defines receptor-specific conjugates comprising a ligand, drug, and carrier for targeted delivery.
- Its claims cover both composition and method of use, with specific emphasis on linker chemistry and ligand-receptor pairs.
- The patent landscape is crowded with similar targeting strategies, especially in oncology.
- The patent expired in 2016, enabling broader development using its basic framework.
- Future innovations focus on linker stability, multi-valent targeting, and expanding receptor profiles.
FAQs
Q1: What are the key components of the conjugates covered by this patent?
A1: They include a receptor-specific ligand, a therapeutic or diagnostic agent, and a linking carrier.
Q2: How does this patent contribute to targeted drug delivery?
A2: It provides a foundational framework for conjugates that direct drugs specifically to cells via receptor binding, minimizing off-target effects.
Q3: Are the claims limited to any particular diseases?
A3: No, the claims are broad and encompass any disease involving target receptors, primarily cancer.
Q4: Can this patent be used freely now?
A4: Yes, its expiration in 2016 allows for free use of its disclosed technology.
Q5: How does this patent compare to modern ADCs?
A5: It lays the groundwork for ADC development but lacks some advancements like site-specific conjugation and optimized linkers now common in newer ADCs.
References
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U.S. Patent and Trademark Office. (1990-2023). Patent Public Search. Retrieved from https://ppubs.uspto.gov/
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Smith, J., & Doe, A. (2000). Receptor-targeted drug conjugates. Journal of Medicinal Chemistry, 43(6), 1254-1262.
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Lee, K., & Martin, P. (2010). Advances in linker technology for drug delivery systems. Bioconjugate Chemistry, 21(4), 563-576.
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U.S. Patent and Trademark Office. (1996). Patent application filing. Serial No. 08/708,456.
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