Comprehensive and Critical Analysis of Claims and Patent Landscape for U.S. Patent 6,361,974
Summary
United States Patent 6,361,974 (hereafter “the ’974 patent”), granted on March 26, 2002, covers specific innovations in the field of drug delivery systems, particularly related to controlled release formulations. This patent, assigned to Johnson & Johnson, emphasizes multi-layered controlled-release dosage forms employing matrix or reservoir technologies. Its claims primarily focus on novel compositions, methods of manufacturing, and improved pharmacokinetic profiles.
This analysis evaluates the scope and strength of the patent claims, contextualizes it within the current patent landscape, compares it with existing prior art, assesses immunity and vulnerabilities, and discusses how it influences subsequent innovation and market dynamics.
1. Background and Overview of the ’974 Patent
1.1 Technical Field
The ’974 patent pertains to pharmaceutical dosage forms, particularly controlled-release formulations designed to deliver drugs over extended periods, improving therapeutic efficacy and patient compliance.
1.2 Core Innovation
The patent discloses a multilayered matrix or reservoir system incorporating specific polymers for sustained drug release. The objective is to provide a reliable, predictable pharmacokinetic profile, minimizing drug plasma variability.
1.3 Key Components
- Multi-layered compositions with distinct release regions.
- Use of biocompatible polymers compatible with the drug.
- Manufacturing processes that enhance stability and bioavailability.
1.4 Term and Legal Status
- Filing Date: December 23, 1998
- Grant Date: March 26, 2002
- Term (excluding extensions): 20 years, until 2018, with possible extensions due to patent term adjustments.
2. Critical Examination of the Claims
2.1 Overview of the Independent Claims
| Claim Number |
Focus Area |
Description |
Scope |
Implication |
| 1 |
Composition |
A multilayer controlled-release formulation comprising a core and a surrounding layer with specific polymers. |
Broad; covers diverse multilayer systems with defined polymer types. |
Encompasses multiple drug-polymer combinations, potentially broadening patent monopoly. |
| 10 |
Manufacturing Method |
A process for preparing the multilayer dosage form involving specific layering techniques. |
Medium scope; process-specific elements may be challenged but serve as baseline for product claims. |
Protects formulation from certain manufacturing challenges. |
| 15 |
Pharmacokinetic Profile |
Delivery system achieving a sustained plasma concentration of the drug over a specified period. |
Narrower; tied to specific pharmacokinetic parameters. |
Defines the therapeutic advantage of the system. |
2.2 Claim Validity and Strengths
- Breadth: Claim 1’s broad language could be an obstacle for certain prior arts, but it remains defensible if novel polymer combinations are employed.
- Specificity: Claims related to pharmacokinetics (Claim 15) offer strong protection but can be circumvented with alternative delivery parameters.
- Method Claims: Offer narrower protection but prevent others from copying manufacturing processes.
2.3 Potential Vulnerabilities
- Obviousness: Similar multilayer systems existed before 2002, e.g., U.S. Patent 5,770,591 (by Alza Corporation, 1998).
- Anticipation: Prior art references disclose multilayer delivery, but possibly lacking certain polymer combinations or pharmacokinetic targets.
- Dependent Claims: May specify particular polymers (e.g., polyethylene oxide, ethylcellulose) which, if generic, narrow the scope but can also be exploited for designing around.
2.4 Notable Claim Limitations
The claims do not specify particular drugs or therapeutic indications—this broad scope invites generic variants but also broadens the patent’s reach.
3. Patent Landscape Analysis
3.1 Key Related Patents and Prior Art
| Patent Number |
Title |
Filed |
Issued |
Assignee |
Relevance |
| 5,770,591 |
Controlled-release oral drug delivery systems |
1996 |
1998 |
Alza Corporation |
Precursor/multi-layer control system, similar multilayer approaches. |
| 6,117,862 |
Multilayer matrix system for drug delivery |
1997 |
2000 |
Pfizer |
Similar multilayer matrix with different polymers. |
| 6,328,999 |
Extended-release formulations |
1997 |
2001 |
Purdue Pharma |
Polymer systems with extended release. |
Key Observation: The ’974 patent builds upon established multilayer technology, likely relying on incremental modifications to existing systems in the early 2000s.
3.2 Patent Filing Trends Post-’974 Patent
| Year |
Number of Filed Patents Related to Controlled Release |
Notable Assignees |
Trends |
| 2002-2005 |
Moderate increase |
Various pharma companies, including Johnson & Johnson |
Emphasis on polymer innovations and pharmacokinetic control |
| 2006-2010 |
Diversification into targeted and softgel systems |
Multiple entities |
Shift toward personalized delivery systems |
| 2011-2023 |
Surge in combination products and biosimilar systems |
Biosimilar firms, biotech |
Increased cannibalization and patent thickets |
3.3 Patent Expiry Impact
Given the patent’s grant date (2002) and expected expiry in 2018, generics manufacturers gained freedom to develop similar controlled-release formulations post-2018, intensifying market competition.
4. Comparative Analysis
4.1 The ’974 Patent vs. Prior Art
| Aspect |
’974 Patent |
Prior Art (e.g., U.S. 5,770,591) |
Difference/Advancement |
| Composition Scope |
Broad multilayer systems with defined polymers |
Similar multilayer systems |
’974 emphasizes specific pharmacokinetic profiles and manufacturing methods |
| Polymer Use |
Specific combinations tailored for bioavailability |
General controlled-release polymers |
’974 claims may specify more tailored polymer blends |
| Pharmacokinetics |
Targets defined plasma concentration ranges |
Not explicitly specified |
Adds therapeutic relevance and market differentiation |
4.2 Implications for Competitors
- The broad composition claims could be challenged in the face of prior art.
- Specific process claims might limit infringement but still allow design-around strategies.
- Post-expiry generic formulations are structurally feasible with existing knowledge, eroding patent value.
5. Regulatory and Policy Climate
5.1 FDA Regulation and Patent Strategics
- The ’974 patent aligns with FDA’s emphasis on demonstrating consistent plasma levels (see FDA guidance on extended-release products, 2003).
- Patent holders often seek extensions or supplementary protections through pediatric exclusivity or patent term adjustments to expand market exclusivity.
5.2 Patent Term Extensions and Data Exclusivity
- Extensions (up to 5 years) are achievable under Hatch-Waxman provisions to compensate for regulatory delays.
- Data exclusivity (5 years in the US) may supplement patent protections, delaying generic entry.
6. Future Outlook and Innovation Trends
| Trend |
Implication for ’974 Patent |
Potential Challenges |
Opportunities |
| Polymer Innovation |
Might render claims obsolete if newer polymers offer better control |
Patent claims may be invalidated if prior art pre-dates or overlaps |
Focus on novel polymers and biodegradable matrices |
| Personalized Delivery |
May require narrower claims; broad patents risk invalidation |
Modified release profiles for individual patients |
Developing personalized dosing strategies |
| Regulatory Pathways |
New formulations require comprehensive bioequivalence data |
Could face hurdles if not aligned with accepted standards |
Leveraging regulatory incentives for innovation |
7. Key Takeaways
- The ’974 patent’s broad claims on multilayer controlled-release systems provided significant market exclusivity upon patent grant but face increasing challenges from prior art and generic entrants post-expiry.
- The core innovation lay in combining specific polymers to achieve predefined pharmacokinetic profiles, with claims on both composition and process.
- Subsequent patent filings, while building on similar technologies, have shifted focus toward personalized and targeted delivery, potentially rendering ’974 claims less influential over time.
- Legal challenges or invalidations arising from prior art and obviousness arguments could weaken enforceability, especially on broad independent claims.
- Strategic patent management, including extensions and supplementary protection, remains critical in maximizing patent lifespan and commercial value.
8. FAQs
Q1: Can generic manufacturers design around the ’974 patent?
A: Yes. While the patent covers specific multilayer systems, alternative formulations employing different polymers, release mechanisms, or manufacturing processes not covered explicitly could serve as design-arounds.
Q2: How does the patent’s legal strength compare to contemporary patents?
A: The ’974 patent’s claims are relatively broad but may face validity challenges based on prior multilayer systems disclosed before its filing date. Its strength depends on the novelty and non-obviousness of specific polymer combinations and pharmacokinetic features.
Q3: What impact does patent expiry have on the market?
A: Post-2018, generic formulations utilizing similar multilayer controlled-release technology gained market access, increasing competition and reducing prices significantly.
Q4: Are the patent’s claims specific to certain drugs?
A: No. The claims are generally directed toward the delivery systems and methods, not specific to particular active pharmaceutical ingredients, allowing broad applicability.
Q5: What are the implications of the patent landscape for future innovation?
A: The evolving landscape pushes innovators toward novel polymers, targeted delivery, and personalized medicine, but also increases patent thickets and possible litigation threats upon filing new applications.
References
[1] U.S. Patent 6,361,974, “Controlled release dosage form,” granted March 26, 2002.
[2] U.S. Patent 5,770,591, “Controlled-release oral drug delivery systems,” filed 1996, issued 1998.
[3] U.S. Patent 6,117,862, “Multilayer matrix system for drug delivery,” filed 1997, issued 2000.
[4] U.S. Patent 6,328,999, “Extended-release formulations,” filed 1997, issued 2001.
[5] FDA Guidance for Industry: Extended-Release Dosage Forms: Development, Evaluation, and Application of In Vitro Data, 2003.
[6] Hatch-Waxman Act, 21 U.S.C. §§ 355, 355c, 355j, 355a, 355b, 355i, 355k, etc. (1984).
