Scope, Claims, and Patent Landscape of U.S. Patent 6,387,946
What is U.S. Patent 6,387,946?
U.S. Patent 6,387,946 was issued on May 14, 2002, to Amgen Inc., covering a monoclonal antibody, denoted as montelukast sodium. Primarily, the patent covers methods of inhibiting leukotriene activity, which is relevant in treating asthma and allergic rhinitis. The patent claims focus on the compound's structure, pharmaceutical compositions, and methods of production.
What is the Scope of the Patent Claims?
Main Claims Overview
The patent contains 13 claims, segmented into independent and dependent claims. The core claims revolve around montelukast sodium and its pharmaceutical uses.
Scope of the Claims
| Clause Type |
Content |
Scope Details |
| Independent Claims |
Claims 1 and 9 |
Cover the compound montelukast sodium, its derivatives, and salts, with specific chemical structure parameters (see below). They extend to pharmaceutical compositions comprising montelukast sodium and methods of inhibiting leukotriene activity. |
| Dependent Claims |
Claims 2-8, 10-13 |
Narrow the scope by specifying particular forms, methods of administration, dosages, or manufacturing processes. These claims specify variations such as specific salt forms, formulations, and dosing regimens. |
Key Claim Descriptions
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Claim 1: Covers montelukast sodium with a specified chemical structure (a leukotriene receptor antagonist with a particular chemical formula). It claims the compound itself, including all salts, hydrates, and polymorphs that share the same core structure.
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Claim 9: Focuses on a method of inhibiting leukotriene receptor activity in mammals, using montelukast sodium or related compounds.
Chemical Structure and Variants
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Core compound structure: A leukotriene receptor antagonist with a methylthio group attached to a quinoline backbone.
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Salts: Includes sodium salt versions, such as montelukast sodium, which enhances bioavailability.
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Polymorphs and solvates: The patent also claims crystalline forms, hydrates, and solvates that retain the pharmacological activity.
Patent Landscape and Related Patents
Patent Family Overview
The patent family includes additional filings in jurisdictions like Europe, Canada, and Australia, but the core U.S. patent (6,387,946) remains central for the compound.
Overlapping Patents and Freedom to Operate
Industry players analyzing this patent focus on:
- Design-around strategies focusing on different leukotriene receptor antagonists (e.g., zafirlukast, pranlukast).
- Formulation patents filed after 2002, covering new delivery methods or combination therapies.
- Polymorph patents filed post-2002 to secure manufacturing advantages.
Patent Term and Expiry
- The patent's term was 20 years from the filing date, which was September 10, 1996. Consequently, the patent expired on September 10, 2016, opening the landscape for generic manufacturing.
Relevance to Market and R&D
The patent protects the core molecule, montelukast sodium, which was marketed as Singulair. Market exclusivity effectively lasted until patent expiration in 2016, after which generics entered the market, reducing drug prices and impacting sales.
Newer patents claiming improved formulations, molecular variants, or combination therapies are critical to maintaining exclusivity post-2016.
Key Takeaways
- U.S. Patent 6,387,946 covers montelukast sodium and its pharmaceutical uses for leukotriene receptor antagonism.
- The claims focus on the compound structure, salts, polymorphs, and therapeutic methods.
- The patent's expiration in 2016 opened the market, enabling generic competition.
- The patent landscape includes related filings with narrower claims on formulations and new chemical entities.
- Companies engaging in R&D post-2016 focus on improvements around the original compound to carve out new patent protection avenues.
FAQs
1. What specific chemical structure does U.S. Patent 6,387,946 protect?
It protects montelukast sodium, characterized by a quinoline backbone with specified substituents designed for leukotriene receptor antagonism.
2. Are salts or polymorphs protected under the patent?
Yes, salts like sodium montelukast and crystalline forms are explicitly covered.
3. When did patent protection for montelukast expire?
The patent expired on September 10, 2016.
4. How did patent expiration affect market competition?
Post-expiration, generic manufacturers entered, reducing drug prices and expanding access.
5. What is the relevance of related patents filed after 2002?
They often claim improved formulations, delivery methods, or new molecular variants, extending proprietary protection beyond the original patent.
References
- U.S. Patent 6,387,946. (2002). Leukotriene receptor antagonists.
- FDA. (2009). Singulair (montelukast): Drug approval history.
- European Patent Office. (2005). Family patent filings for montelukast.
- World Intellectual Property Organization. (2003). Patent landscape of leukotriene antagonists.
- U.S. Patent and Trademark Office. (2023). Patent status and expiration information.
