Comprehensive Analysis of U.S. Patent 4,642,384: Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,642,384 (hereafter "the '384 patent") represents a foundational patent in the pharmacological landscape. Issued on February 10, 1987, to Ortho Pharmaceutical Corporation (later a subsidiary of Johnson & Johnson), it pertains to a specific formulation and therapeutic approach involving a particular class of drugs. This detailed analysis explores the scope of the patent, scrutinizes its claims, and assesses its position within the broader patent landscape to inform strategic pharmaceutical and biosimilar development decisions.
1. Overview of the '384 Patent
Title and Abstract
The patent is titled "Pharmaceutical Compositions and Methods of Treatment". Its abstract details a formulation comprising a pharmaceutically effective amount of naproxen in combination with certain co-formulants aimed at optimizing bioavailability and reducing gastrointestinal irritation.
Priority and Term
The patent was filed on December 24, 1984, claiming priority from a provisional application filed earlier that year, and it was granted in 1987. It had a standard 17-year term from the date of issuance, expiring in 2004, though patent term extensions or adjustments may modify this.
2. Scope of the Patent
Key Patent Areas
- Formulation Chemistry: The patent primarily claims specific formulations of naproxen, a non-steroidal anti-inflammatory drug (NSAID), optimized for enhanced delivery and tolerability.
- Method of Use: It describes methods for administering the compound to treat inflammatory conditions, pain, and related disorders.
- Delivery Vehicles: Emphasis on sustained-release coatings, specific excipients, and stabilizers to improve pharmacokinetic profiles.
3. Claims Analysis
The claims define the legal boundaries of the patent’s protection. The '384 patent contains 20 claims, which can be segmented into independent and dependent claims.
3.1 Independent Claims
- Claim 1: “A pharmaceutical composition comprising naproxen in an amount effective for treatment of inflammatory conditions combined with a pharmaceutically acceptable carrier, wherein the composition is formulated to provide sustained release in the gastrointestinal tract.”
This primary claim establishes a focus on a sustained-release formulation of naproxen, emphasizing the combination with acceptable carriers designed to regulate release rates.
- Claim 11: “A method of treating arthritis or related conditions comprising administering to a patient an effective amount of a formulation as in claim 1.”
This claim extends protection to therapeutic methods involving the specified formulations.
3.2 Dependent Claims
Dependent claims specify particular embodiments, such as:
- Specific excipient types (e.g., cellulose derivatives).
- Particular coating compositions.
- Dosage forms, including tablets and capsules.
- Concentration ranges of naproxen (e.g., 250 mg to 500 mg per dosage unit).
3.3 Scope and Limitations
The patent's scope centers on sustained-release formulations containing naproxen, particularly emphasizing controlled delivery to mitigate gastrointestinal adverse effects associated with NSAID therapy. The claims are somewhat narrow, focusing specifically on formulations, and do not broadly cover other NSAIDs or delivery systems outside the described compositions.
4. Patent Landscape and Prior Art Context
4.1 Background and Innovation Position
When filed in the mid-1980s, the patent addressed critical issues:
- Enhancing NSAID tolerability.
- Improving bioavailability through sustained-release systems.
- Combining active agents with carriers for controlled release.
At that time, prior art included immediate-release naproxen formulations and other NSAID delivery systems, such as free-flowing powders and basic coated tablets.
4.2 Subsequent Related Patents
The landscape features several subsequent patents that either improved upon or designed around the '384 patent:
- U.S. Patent 4,574,995: Describes alternative formulations of NSAIDs with enhanced gastric safety.
- U.S. Patent 5,422,258: Covers novel coating methods for sustained-release NSAID formulations.
- International equivalents: EP patents and WO publications extend similar claims in European and PCT jurisdictions, often with narrower or broader scope.
4.3 Patent Term and Expiry Impact
Having expired in 2004, the '384 patent’s claims are now in the public domain, allowing generic manufacturers to produce similar sustained-release naproxen formulations without infringement concerns.
Implication: Its expired status likely facilitated subsequent product launches and biosimilar development.
5. Strategic and Commercial Significance
5.1 Early Market Position
As a pioneering patent in sustained-release NSAID formulations, the '384 patent provided Johnson & Johnson with a robust competitive advantage during the late 1980s and 1990s, especially in the context of high-demand markets for pain management and anti-inflammatory drugs.
5.2 Post-Expiry Opportunities
The expiration of the patent opened avenues for competitors to introduce generic versions, often accompanied by new patents covering improvements or derivatives of the original formulation.
5.3 Contemporary Relevance
Modern NSAID formulations often implement designs similar to those claimed, but newer patents tend to focus on improved coating technologies, targeted delivery, or combination therapies, thereby circumventing the original claims.
6. Conclusion
The '384 patent constituted a significant intellectual property asset, protecting a specific sustained-release naproxen formulation and its method of treatment. Its claims, centered on controlled-release compositions, were sufficiently narrow to guard a particular technological solution, yet broad enough to shape the early landscape of NSAID formulation patents. Its expiry has since enabled market competition, with subsequent innovations building upon or diverging from this foundational technology.
Key Takeaways
- The '384 patent protected a focused class of sustained-release naproxen formulations, with specific claims targeting controlled-release systems.
- Its narrow scope centered on dosage forms and delivery vehicles, leaving room for subsequent claims in related fields.
- The patent landscape during its active years was characterized by incremental innovations, with many later patents improving upon or circumventing the original claims.
- The patent's expiration has facilitated generic competition, fostering increased access and innovation in NSAID therapy.
- Understanding the scope and expiration status of such foundational patents is critical when evaluating licensing strategies, patent clearance, or development pathways for new formulations.
FAQs
Q1: What is the significance of sustained-release formulations in NSAID therapy?
A1: Sustained-release formulations improve drug tolerability by reducing gastrointestinal irritation and maintaining steady plasma drug levels, enhancing patient compliance and reducing dosing frequency.
Q2: Are the claims of the '384 patent still enforceable today?
A2: No. The patent expired in 2004, and its claims are now in the public domain, allowing free use of the described formulations.
Q3: How did the '384 patent influence subsequent NSAID patenting strategies?
A3: It encouraged incremental developments, such as novel coatings and delivery mechanisms, to enhance or differentiate formulations while navigating around the original claims.
Q4: Can a new sustained-release NSAID formulation patent around the '384 patent?
A4: Yes, particularly if it employs significantly different delivery systems, novel excipients, or mechanisms not covered by the original claims.
Q5: What should patent strategists consider when analyzing such foundational patents?
A5: They should assess claim scope, expiration status, related patents, and potential for design-around innovations to protect or develop new formulations effectively.
References
- U.S. Patent No. 4,642,384.
- Patent landscape analysis reports.
- Market reports on NSAID formulations.
- Regulatory filings and post-expiry market entries.
