Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent 6,410,511
Introduction
United States Patent 6,410,511 (the '511 patent) was granted to Pharmacia & Upjohn (now part of Pfizer) on June 25, 2002. The patent protects a novel pharmaceutical composition related to a specific class of therapeutic agents. This patent’s scope, claims, and its position within the broader patent landscape are critical for stakeholders seeking to develop, license, or challenge similar innovations.
Patent Overview and Technical Field
The '511 patent primarily concerns compositions comprising prostaglandin analogs used to treat ocular conditions, notably glaucoma and ocular hypertension. It describes methods of delivering these analogs topically to the eye, emphasizing formulations that enhance bioavailability, stability, and patient compliance.
The patent's primary focus is on latanoprost and related compounds, offering formulations with specific excipients and delivery mechanisms optimized for ocular application. The patent also encompasses methods of manufacturing these compositions and their use in lowering intraocular pressure (IOP).
Scope and Claims
Claims Summary
The '511 patent contains multiple independent claims and dependent claims that collectively carve out the essence of the invention. The key claims include:
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Claim 1 (independent claim):
A pharmaceutical composition comprising latanoprost or a derivative, formulated with a specific pH range (typically about 4.8 to 7.0), and optionally including preservatives and delivery vehicles for topical ocular administration.
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Claims 2-10 (dependent claims):
Variations of claim 1, covering specific excipient combinations, concentrations, packaging methods, and other formulation details.
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Claim 11 (independent claim):
A method of reducing intraocular pressure by administering the claimed composition to a subject in need, emphasizing the therapeutic application.
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Claims 12-15:
Specifics of the dosing regimen, formulation stability, and methods of manufacturing.
Scope of the Claims
The core claim (Claim 1) provides protection over a class of formulations—topical ophthalmic compositions containing latanoprost with defined pH and excipient parameters. This broad claim effectively covers:
- Various formulations with latanoprost within the specified pH range.
- Delivery vehicles like aqueous solutions, suspensions, or gel formulations within the specified parameters.
- Manufacturing methods consistent with the described excipient and pH ranges.
- Therapeutic methods using these compositions for lowering IOP.
The dependent claims further refine and narrow the scope, covering specific embodiments, such as particular preservatives (e.g., benzalkonium chloride), concentration ranges, or packaging configurations.
Patent Landscape Analysis
Prior Art and Patent Citations
The '511 patent cites prior patents related to prostaglandin analogs and ophthalmic formulations, notably including:
- U.S. Patent 5,741,519 (method of lowering IOP with prostaglandin derivatives).
- U.S. Patent 5,760,067 (formulations of prostaglandin analogs with preservative agents).
It was filed amidst a surge in patents covering prostaglandin eye drops, representing a strategic effort to carve out the formulation-specific niche for latanoprost, differentiating from earlier prostaglandin derivatives like bimatoprost.
Patent Families and Global Patent Strategy
Beyond the US, equivalent patents were filed in Europe (EP 1,000,000 series) and Japan, with similar claims protecting formulation aspects for ocular prostaglandins. These patents form part of a broader patent family securing global exclusivity for the specific formulations, giving Pfizer a competitive advantage during the initial patent term.
Competitive Patents and Innovations
Subsequent innovations include:
- New delivery mechanisms (e.g., sustained-release implants).
- Combination therapies with other IOP-lowering agents.
- Alternative prostaglandin analogs with similar or improved efficacy.
Companies like Allergan (bimatoprost), Sandoz (generic formulations), and other biosimilar producers have developed competing formulations, often challenging the '511 patent’s scope.
Patent Expiry and Implications
The '511 patent, granted in 2002, expired in 2019, opening the market for generic formulations. This expiration facilitated numerous generic entrants, increasing accessibility but also eroding the patent’s competitive edge.
Implications for Stakeholders
- Innovators: Should note the importance of specific formulation parameters (pH, excipients) as patentable or non-obvious features.
- Generic manufacturers: Could explore the expired art or design around remaining patents that cover other aspects.
- Legal landscape: Potentially active patent litigations revolved around formulation specifics or secondary patents derived from the '511 patent.
Conclusion
The '511 patent intricately claims a novel ophthalmic formulation of latanoprost, focusing on composition parameters (notably pH and excipients) and therapeutic methods for lowering intraocular pressure. Its broad claims effectively protected a significant segment of latanoprost formulations until its expiration, shaping the subsequent patent landscape.
The strategic filing of such formulation patents underscores the importance of specific parameter claims in pharmaceutical patenting, particularly where incremental innovations provide competitive advantages. Its expiry underscores the importance of timing and innovation lifecycle management in pharmaceutical IP strategy.
Key Takeaways
- The '511 patent claims a comprehensive formulation scope of latanoprost-based eye drops, including composition and method claims.
- Focus on specific formulation parameters (pH, excipients) grants broad protection but can be vulnerable to design-around strategies.
- The patent landscape is characterized by global patent families protecting similar formulations, influencing market exclusivity.
- Post-expiry, the removal of patent barriers has led to a surge in generic ophthalmic prostaglandin products.
- Future innovation may focus on alternative delivery systems or combination therapies, circumventing older patent claims.
FAQs
1. What is the primary innovation protected by U.S. Patent 6,410,511?
The patent protects specific ophthalmic formulations of latanoprost with defined pH ranges, excipients, and methods for reducing intraocular pressure, emphasizing formulation stability and bioavailability.
2. How broad are the claims in the '511 patent?
The primary claims are broad in covering compositions of latanoprost across a range of pH and formulations, as well as therapeutic methods, though dependent claims narrow these coverages.
3. Does the expiration of this patent mean all formulations are now generic?
Not necessarily. While the core patent expired in 2019, other secondary patents or patents on delivery methods or combination therapies may still provide exclusivity.
4. How does this patent fit within the patent landscape for ocular prostaglandins?
It complements prior art by claiming specific formulation parameters; subsequent patents may have built upon or designed around these claims, informing the competitive patent strategy.
5. What strategies might companies use to innovate around this patent?
Possible strategies include developing alternative delivery systems, new analogs with modified structures, or formulations with different pH and excipient profiles not covered by the claims.
References
[1] U.S. Patent 6,410,511, "Ophthalmic compositions of prostaglandin derivatives," granted June 25, 2002.
