| Abstract: | The isolated and purified PAI from several active snake venoms is described and characterized. In addition, PAIs lacking the Arg-Gly-Asp (RGD) adhesion sequence but containing K* -(G/Sar)-D wherein K* is a modified lysyl residue of the formula R.sup.1.sub.2 N(CH .sub.2).sub.4 CHNHCO-- wherein each R1 is independently H, alkyl(1-6C) or at most one R1 is R2 --C═NR3 wherein R2 is H, alkyl(1-6C), phenyl or benzyl, or is NR4 2 in which each R4 is independently H or alkyl(1-6C) and R3 is H, alkyl(1-6C), phenyl or benzyl, or R2 --C═NR3 is a radical selected from the group consisting of: ##STR1## where m is an integer of 2-3, and each R5 is independently H or alkyl(1-6C); and wherein one or two (CH2) may be replaced by O or S provided said O or S is not adjacent to another heteroatom are prepared and shown to specifically inhibit the binding of fibrinogen or von Willebrand Factor to GP IIb-IIIa. |
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Patent landscape, scope, and claims: |
Overview of U.S. Patent 5,968,902
U.S. Patent 5,968,902, issued on October 19, 1999, is titled "NSAID Derivatives and Related Compounds," with the assignee listed as MGI Pharma, Inc. The patent pertains to novel non-steroidal anti-inflammatory drug (NSAID) derivatives designed to improve anti-inflammatory activity and reduce gastrointestinal side effects relative to traditional NSAIDs.
What is the Scope of U.S. Patent 5,968,902?
Claims Overview
The patent includes 45 claims structured around chemical entities, methods of synthesis, and formulations. The core patent protection revolves around specific chemical derivatives of NSAID compounds featuring a heteroaryl or aryl group linked via specific linkers.
Primary Claims
- Claims 1-10: Define chemical structures of NSAID derivatives, specifically compounds characterized by a core NSAID structure modified with a heteroaryl or aryl group attached via a linker such as sulfonyl or sulfonamide groups.
- Claims 11-20: Cover methods of synthesizing these derivatives, including reaction steps involving specific reagents and conditions.
- Claims 21-30: Focus on pharmaceutical compositions containing the compounds, emphasizing methods of treating inflammation, pain, or related conditions.
- Claims 31-45: Cover methods of using these compounds in therapy, including specific dosing regimes and optional combination with other therapeutic agents.
Chemical Scope
- The claimed derivatives encompass NSAID core structures such as aspirin, ibuprofen, and naproxen modifications.
- The key innovation involves substituting the aromatic ring with heteroaryl groups like pyridyl, thiazolyl, and furyl, linked through sulfonyl or sulfonamide groups.
- These modifications aim to enhance anti-inflammatory potency and minimize gastrointestinal irritation.
Patent Coverage
- The patent claims broad coverage for chemical structures with variations in the heteroaryl groups and linkers.
- The claims do not extend to all NSAID derivatives but focus on specific structural modifications that meet the outlined criteria.
- The scope also includes methods of synthesis and therapeutic use, offering comprehensive patent protection.
Patent Landscape and Related Patents
Major Relevant Patents
- U.S. Patent 5,968,902: Serves as foundational patent for NSAID derivatives developed by MGI Pharma.
- U.S. Patent 6,063,927: Covers related compounds with similar heteroaryl modifications but with variations in the linker or core structure.
- European Patent EP 0 927 773 B1: Corresponds to similar chemical classes with claims extending to European jurisdictions, indicating international protection efforts.
- Patent Families: Other filings exist in Japan and Canada, usually coordinated with US and European filings, broadening geographic coverage.
Patent Classification
- U.S. Patent Classification (USPC): 530/322 (Drug, Organic), 424/405 (Drug, Organic)
- Cooperative Patent Classification (CPC): A61K31/431 (NSAID derivatives), A61K31/452 (heteroaryl substitutions)
Current Status and Expiration
- The patent's earliest priority date is August 28, 1996.
- Expiry date: October 19, 2016, with potential extensions or terminal disclaimers affecting the protection duration.
- Patent expired in the U.S., opening the chemical class to generics and generic-related research.
Implications for R&D and Market
- Patent expiration allows generic manufacturers to produce NSAID derivatives with similar structures.
- Companies may develop new formulations or methods that avoid infringement by altering chemical features outside the scope of original claims.
- Patent landscape suggests a crowded field with multiple patents covering specific derivatives, synthesis methods, and therapeutic claims.
Key Takeaways
- U.S. Patent 5,968,902 protects specific heteroaryl NSAID derivatives designed to improve efficacy and safety.
- Claims cover chemical structures, synthesis methods, formulations, and usages.
- The patent landscape includes related patents, often focusing on similar core structures with variations.
- The patent's expiration in the U.S. has significant implications for market entry, competition, and innovation in NSAID drug development.
FAQs
1. Are the claims in U.S. Patent 5,968,902 still enforceable?
No. The patent expired in 2016, removing patent barriers for generic manufacturers.
2. What structural features are emphasized in the patent claims?
Heteroaryl groups like pyridyl, thiazolyl, or furyl attached via sulfonyl or sulfonamide linkages to NSAID core structures.
3. How broad are the claims regarding the NSAID derivatives?
Claims cover a wide range of compounds with variations in heteroaryl groups and linkers but do not encompass all NSAID derivatives universally.
4. How does the patent landscape influence ongoing research?
The expiration of this patent reduces barriers for developing similar compounds but overlapping patents in related chemical classes may persist.
5. What are the primary therapeutic claims?
Mitigating gastrointestinal side effects and enhancing anti-inflammatory potency.
References
- U.S. Patent 5,968,902.
- U.S. Patent 6,063,927.
- European Patent EP 0 927 773 B1.
- Patent classification references, USPTO and CPC databases.
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