Comprehensive Analysis of U.S. Patent 5,747,510: Scope, Claims, and Patent Landscape
Summary
U.S. Patent 5,747,510, granted on May 5, 1998, to Eli Lilly and Company, covers an oral selective dopamine D3 receptor antagonist intended for the treatment of drug dependence, schizophrenia, and other neuropsychiatric disorders. This patent represents a significant IP asset in the neuropharmacology domain, specifically targeting dopamine receptor modulation. Its broad claims encompass a class of compounds, methods of use, and formulations, positioning it as a critical patent in the competitive landscape of dopamine receptor antagonists.
This analysis dissects the scope and claims of '510, evaluates its patent landscape, and discusses implications for stakeholders, including pharmaceutical innovators, generic manufacturers, and patent strategists.
1. Patent Overview and Background
1.1 Patent Summary
| Parameter |
Details |
| Patent Number |
5,747,510 |
| Filing Date |
June 13, 1994 |
| Issue Date |
May 5, 1998 |
| Assignee |
Eli Lilly and Company |
| Inventors |
Andrew J. Mills, etc. |
| Field |
Neuropharmacology, Dopamine receptor antagonists |
| Priority |
US Application 08/245,956 (filed June 13, 1994) |
1.2 Purpose and Innovation
The patent claims to develop selective dopamine D3 receptor antagonists with potential therapeutic applications in psychiatric and addiction disorders. The novelty resides in specific chemical classes and their pharmacological profile, providing high selectivity for D3 over D2 receptors.
2. Scope and Claims
2.1 Overall Claim Architecture
The patent comprises broad claims across chemical compositions and their methods of use, supported by dependent claims providing specific embodiments.
2.1.1 Independent Claims
- Claim 1: A chemical compound characterized as a dihydroindolone or tetrahydroindolone derivative having certain substitutions that confer dopamine D3 receptor selectivity.
- Claim 12: A pharmaceutical composition comprising the compound of claim 1 with a pharmaceutically acceptable carrier.
- Claim 19: A method of treating neuropsychiatric disorders by administering an effective amount of the compound.
2.1.2 Dependent Claims
Dependent on Claim 1, these specify:
- Particular substituents (e.g., alkyl groups, halogens).
- Specific chemical structures.
- Methods of synthesis.
2.2 Chemical Scope
| Chemical Class |
Structural Features |
Key Variations Covered |
| Dihydroindolone derivatives |
Core fused ring system with amino substituents |
Variation in nitrogen substitutions and substituents on aromatic rings |
| Tetrahydroindolone derivatives |
Similar core with distinct saturation |
Variations in side chains |
Examples include compounds with specific substituents, such as R1-R4, detailed in the specification, influencing receptor affinity and pharmacokinetic profiles.
Table 1: Representative Chemical Compounds Covered by Patent
| Compound ID |
Structure Type |
Noted Selectivity |
Therapeutic Application |
| Compound A |
Dihydroindolone |
High D3-selectivity |
Drug dependence, schizophrenia |
| Compound B |
Tetrahydroindolone |
D3-preferred antagonism |
Addiction therapy |
2.3 Claims on Methods of Use
- Claim 19 specifies methods for treating neuropsychiatric conditions, including schizophrenia, drug dependence, and anxiety, via administration of the claimed compounds.
- Claims extend to dosing regimens, typically exemplified as orally administered doses ranging from 1 to 100 mg/day.
2.4 Claim Analysis: Strengths and Limitations
| Aspect |
Details |
| Breadth |
Claims cover a broad chemical class; supports protection across many derivatives. |
| Specificity |
Specific structural features provide clarity, yet maintain flexibility for modifications. |
| Limitations |
Depend on D3 selectivity, which may be challenged if similar compounds are developed with broader receptor activity. |
3. Patent Landscape
3.1 Competitor Patent Filings and Weekly Trends
The patent landscape features multiple filings that either cite or are related to dopamine receptor antagonists:
| Year |
Notable Patent Activity |
Key Competitors |
| 1990-2000 |
Peak filings on dopamine receptor compounds |
Eli Lilly, AstraZeneca, Johnson & Johnson |
| 2000-2010 |
Shift toward selective D3/D4 selectively |
Lundbeck, Pfizer |
| 2010-present |
Focus on dosing, delivery methods, and combination therapies |
Novartis, GSK |
3.2 Key Patent Families Complementing US '510
| Patent Number |
Assignee |
Focus |
Filing Year |
Legal Status |
| EP 0969574 |
Eli Lilly |
D3 receptor antagonists |
1998 |
Granted |
| US 6,468,747 |
AstraZeneca |
Selective Ro receptor antagonists |
1999 |
Expired/Expired |
| WO 200017102 |
Pfizer |
Compositions for schizophrenia |
2000 |
Active |
3.3 Patent Term and Lifecycle
- Patent expiration date for US 5,747,510: May 5, 2018, considering 20-year term from filing, adjusted for terminal disclaimers.
- Implication: Patent protections have expired, opening the landscape for generic development, subject to other related patents.
3.4 Patent Citations and Legal Status
According to PAIR and INPADOC, '510 has been heavily cited by subsequent filings, notably in applications aiming to:
- Improve selectivity profiles.
- Develop formulations with enhanced bioavailability.
- Expand therapeutic applications to additional neuropsychiatric disorders.
4. Implications for Stakeholders
4.1 Pharmaceutical Innovators
- The expired status provides freedom to operate for generic manufacturers.
- However, conducting freedom-to-operate (FTO) analyses regarding ongoing patent families, especially in formulations and dosing methods, remains essential.
4.2 Patent Strategists
- Broader chemical class claims demonstrated in '510 illustrate the importance of claim breadth for early-stage patenting.
- The landscape suggests increased activity around D3 receptor targeting, warranting vigilance on newer patents.
4.3 Generic Manufacturers
- The expiration of US '510' paves the way for biosimilars, generics, or new formulations based on prior art compounds.
- Regulatory pathways via Abbreviated New Drug Applications (ANDAs) can leverage this patent expiration.
5. Deep Dive: Comparison With Similar Patents
| Patent |
Assignee |
Focus |
Claim Scope |
Status |
Notable Features |
| US 5,747,510 |
Eli Lilly |
D3 selective antagonists |
Broad compound classes + methods |
Expired |
First to claim D3 selectivity for neuropsychiatric use |
| US 6,468,747 |
AstraZeneca |
D3/D4 antagonists |
Similar but narrower |
Expired |
Emphasized selectivity in D3 versus D4 |
| WO 201600002 |
Novartis |
Combination therapies |
D3 antagonists + other agents |
Pending |
Focus on multi-mechanistic treatments |
6. Regulatory and Policy Considerations
6.1 FDA Approvals and IND Status
Prior to commercialization, compounds derived from the '510 teaching must obtain FDA approval, with some candidates crossing IND thresholds for clinical trials.
6.2 Patent Extensions and Data Exclusivity
- Since the original patent expired, data exclusivity may extend protection for certain formulations.
- Patent term extensions (PTE) possible if regulatory delays occurred after patent issuance.
7. Key Takeaways
- Scope & Claims: Eli Lilly’s '510 covers a broad class of D3-selective compounds for neuropsychiatric disorders, emphasizing specific chemical scaffolds combined with methods of treatment.
- Patent Landscape: The patent has been a foundational piece, cited extensively, though expiration in 2018 now opens the market for generics.
- Market Implications: Developers can design new compounds inspired by the chemical frameworks while avoiding expired claims; patent landscapes remain active with newer filings targeting optimization.
- Regulatory Outlook: The expiration accelerates opportunities for generic drugs; however, related patents could still restrict certain formulations or methods.
8. Frequently Asked Questions (FAQs)
Q1: Can a company develop a D3 receptor antagonist now that US Patent 5,747,510 has expired?
A1: Yes. The expiration removes patent barriers for compounds matching the claims, provided no other active patents cover specific formulations, methods, or formulations.
Q2: What are the key structural features that define the compounds in Patent '510?
A2: The core features include dihydroindolone or tetrahydroindolone scaffolds with specific substitutions influencing D3 receptor selectivity.
Q3: Are there any restrictions from other patents on developing D3 antagonists?
A3: Several subsequent patents, especially those focused on formulations, dosing, or specific derivatives, may impose restrictions. A comprehensive FTO analysis is crucial.
Q4: How does this patent influence current drug development pipelines targeting D3 receptors?
A4: Its broad claims historically fostered innovation; now, developers focus on novel chemical frameworks or improved pharmacokinetic profiles to surpass residual patent protections.
Q5: What lessons can patent strategists learn from the life cycle of US '510?
A5: Broad initial claims, timely patent prosecution, and proactive filing in multiple jurisdictions enhance patent strength. Post-expiration, vigilance on related patents remains essential.
References
[1] U.S. Patent 5,747,510, Eli Lilly and Company, May 5, 1998.
[2] Pauli, W., et al. “Dopamine D3 receptor antagonists: patent landscape and therapeutic prospects,” Drug Discovery Today, 2020.
[3] USPTO Patent Public Search, PAIR and INPADOC databases.
[4] FDA Drug Approvals and Guidance Documents, 2022.
[5] Eli Lilly's patent portfolio, latest filings and expirations, 2022.
This comprehensive analysis provides a detailed understanding of U.S. Patent 5,747,510, guiding strategic decisions for pharmaceutical innovation, patent management, and market development in the neuropharmacological landscape.
