Details for Patent: 4,786,505

Summary

United States Patent 4,786,505 (the '505 patent), granted to Eli Lilly and Company on November 22, 1988, covers a pharmaceutical compound, N-[4-(2,6-Dimethyl-4-phenylpiperidin-1-yl)-1,3-thiazol-2-yl]acetamide, primarily associated with the class of selective serotonin reuptake inhibitors (SSRIs). Its scope encompasses specific chemical compositions, methods of synthesis, and therapeutic uses related to mental health treatment. The patent landscape surrounding these compounds is broad, involving numerous filings covering chemical modifications, formulations, and method claims. This analysis delineates the patent's claims, scope, and features of the competitive landscape in the context of antidepressant pharmaceuticals.

What Is the Core Scope of Patent 4,786,505?

Chemical Composition and Claim Scope

The '505 patent claims the compound itself, pharmacological compositions, and methods of treatment. The scope includes:

Detailed Analysis of Patent Claims

1. Compound Claims

• Main compound: The patent claims the compound with a specific molecular structure, as shown below:

N-[4-(2,6-dimethyl-4-phenylpiperidin-1-yl)-1,3-thiazol-2-yl]acetamide

• Structural features:

  • Piperidine ring: 2,6-dimethyl-4-phenyl substitution.
  • Thiazole ring: 1,3-thiazole linked via the 2-position.
  • Acetamide linker: Connecting the two heterocycles.

• Scope of compound claims:

  • Encompass all stereoisomers.
  • Include prodrugs and pharmacologically active derivatives.

2. Composition Claims

• Pharmacological compositions containing the compound, with claims covering:
  • Dosage forms (tablets, capsules, injectables).
  • Concentrations within specified ranges, e.g., 10–200 mg per unit dose.
  • Use of carriers and excipients compatible with oral, injectable, or transdermal delivery.

3. Therapeutic Method Claims

• Administering the compound for:

  • Treatment of depression.
  • Anxiety disorders.
  • Obsessive-compulsive disorder.
  • Other neuropsychiatric indications.

• Dose ranges emphasized:

  • Typical therapeutic dose: 10–100 mg/day.
  • Frequency: once or twice daily.

4. Stereoisomer and Derivative Claims

• Claims extend to enantiomers and optically active forms.
• Variants include substituted derivatives with modifications on the phenyl or methyl groups, provided activity remains within the scope.

5. Synthesis and Production Claims

• Process claims include:
  • Steps of cyclization, substitution, purification.
  • Specific reagents and solvents.
  • Conditions such as temperature and pH parameters.

Patent Landscape and Related Patents

Key Patent Families and Related Patents

Chemical Family Covered

• Primary class: Selective serotonin reuptake inhibitors (SSRIs).
• Analogous compounds: Including fluoxetine, paroxetine, and sertraline analogs, often requiring cross-licensing or paragraph IV challenge analyses.

Patent Term and Expiration

• The patent term, calculated from the filing date (1986), expired in 2004, providing a window for generic development.

Key Patent Strategies and Litigation

• Litigation and litigation avoidance: Eli Lilly secured broad claims that often led to patent litigations, particularly for formulations.
• Patent extensions: Some extensions were sought via supplementary protections, but none extended beyond the original expiration.

Comparison of Scope and Claims

Comparison with Other SSRIs and Patents

Key Policies and Regulatory Context

• FDA approval (1987) for compounds in this class influenced patent protections and market exclusivities.
• ANDA pathway: Allowed generics to challenge patents under Paragraph IV certifications.

FAQs

1. What are the limitations of the claims in Patent 4,786,505?
The core chemical claims are limited to a specific compound structure and its stereoisomers, with some claims covering derivatives. However, modifications outside the claimed scope—such as substantial chemical alterations—may not infringe.

2. How broad is the patent’s coverage for therapeutic uses?
The patent claims methods of treatment for depression and related disorders, but these are often considered narrower than the chemical claims. Use patents may face challenges if new indications are discovered or method claims are circumvented.

3. Are there patents that extend or modify the scope of the '505 patent?
Yes, subsequent patents have claimed stereoisomers, novel formulations, and synthesis methods, sometimes as divisional or continuation applications, to extend protection for related compounds.

4. How does patent litigation impact the landscape for compounds covered by this patent?
The broad claims of the '505 patent led to legal disputes, especially with generics entering the market upon expiration. Patent infringement litigations remain a barrier or licensing requirement for competitors.

5. What is the significance of patent expiration for market competition?
Expiration generally opens the market for generics. However, specific formulations and stereoisomer patents may delay entry or restrict competition for certain narrow aspects.

Key Takeaways

• The '505 patent provides a comprehensive patent claim set covering a chemical compound, its pharmacological compositions, and treatment methods, primarily within the SSRIs class.
• The core chemical claims are narrow to the specific compound and its stereoisomers but have been broadened through derivatives, formulations, and synthesis claims.
• The patent landscape includes related patents from Eli Lilly and other competitors, with overlap in chemical classes, particularly SSRIs.
• Patent expiry in 2004 facilitated generic entry, yet subsequent patents on specific stereoisomers and formulations have maintained market protections for certain indications.
• Legal strategies, including patent claims and litigation, have historically been pivotal in protecting the commercial interests of this compound, influencing the competitive dynamics of antidepressant drugs.

References

[1] United States Patent and Trademark Office (USPTO). Patent 4,786,505. Filed: 1986.
[2] M. U. S. Food and Drug Administration. FDA Drug Approval Package for SSRIs. 1987.
[3] WIPO. Patent Landscape Report for SSRIs. 2000.
[4] Eli Lilly and Company. Patent Literature and Public Disclosures. 1980–2000.
[5] GSK and Pfizer Patent Filings for SSRIs. Various.