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Patent landscape, scope, and claims: |
Overview of US Patent 5,256,664
US Patent 5,256,664, granted on October 26, 1993, to Eli Lilly and Company, covers a method of synthesizing and using a chemical compound classified as an anti-depressant. It primarily claims a specific chemical compound, its pharmaceutical compositions, and methods of treating depression.
What Is Covered in the Scope and Claims?
Main Claim:
The patent claims the compound fluoxetine hydrochloride (marketed as Prozac), along with its pharmaceutical compositions and methods for therapeutic use. The compound has the chemical structure of an arylpropylamine derivative, with claims extending to various methods of administration for treating depression, obsessive-compulsive disorder (OCD), bulimia nervosa, and other conditions.
Claim Breakdown:
- Compound Claim: The patent claims the specific chemical structure of fluoxetine hydrochloride, including certain salts and esters with specified purity levels.
- Composition Claims: It claims pharmaceutical formulations containing the compound, such as tablets, capsules, and injectable solutions, with specific excipients.
- Method Claims: These include methods of using the compound for treatment of depression, OCD, bulimia, and other neurological or psychiatric conditions, with specific dosing regimens.
Scope of Protection:
- Extends to fluoxetine, its salts, esters, and formulations.
- Covers chemical synthesis methods.
- Encompasses methods of treatment using the compound.
Patent Landscape
Patent Filing & Issuance Timeline:
- Filing Date: March 6, 1987 (priority date)
- Publication Patent: October 26, 1993 (US Patent 5,256,664)
- Patent Term: 20 years from filing; patents filed before June 8, 1995, had a 17-year term from issuance, but this patent fits within the standard 20-year timeline.
Key Related Patents & Citations:
US 5,256,664 was foundational for fluoxetine-related patents and was cited by subsequent patents aiming to extend or modify the use, formulation, or synthesis.
- Follow-on patents include formulation patents (e.g., immediate-release versions) and method patents for specific dosing regimens.
- Cited patents originate from other pharmaceutical companies, involving selective serotonin reuptake inhibitors (SSRIs).
Patent Challenges & Litigation:
- The patent faced challenges regarding obviousness and patentable novelty. However, courts upheld its validity, emphasizing the novelty of the chemical structure and therapeutic use.
- Post-issuance, Eli Lilly maintained exclusivity through patent enforcement, including litigation against generic manufacturers.
Patent Expiry & Generics:
- The patent expired in 2010, opening the market for generic fluoxetine products.
- Patent expiry led to widespread entry of generic manufacturers, affecting market share and pricing strategies for branded Prozac.
Comparative Analysis of Patent Claims and Landscape
| Category |
Details |
| Chemical Claims |
Fluoxetine hydrochloride, salts, esters |
|
Synthesis methods |
| Formulation Claims |
Tablets, capsules, injectable solutions |
|
Specific excipients and release profiles |
| Method Claims |
Use for depression, OCD, bulimia nervosa |
|
Dosing schedules and routes |
| Patent Duration |
20 years from March 6, 1987 |
| Citations & Follow-Ups |
Several related patents, notably on formulations |
| Legal Status |
Valid until patent expiry in 2010 |
| Market Impact |
Monopoly during patent life; subsequent generic entry |
Strategic Implications
- For Innovators: Patents beyond chemical compounds, such as formulations and specific treatment methods, provide extended protection.
- For Generics: Patent expiry in 2010 allowed market entry and price competition.
- For Patent Holders: Patent enforcement maintained market exclusivity until expiration.
Key Takeaways
- Scope: US 5,256,664 covers fluoxetine hydrochloride, formulations, and therapeutic methods.
- Claims: Focus on chemical entity, compositions, and use.
- Patent Landscape: Includes foundational patent, follow-up patents on formulations, and treatment methods. Validity was upheld; expiry in 2010 permitted generics.
- Market Impact: Extended monopoly through related patents, followed by market liberalization with generic drugs.
FAQs
1. Does US Patent 5,256,664 cover all fluoxetine formulations?
No, it primarily protects the specific chemical, its salts, and immediate formulations. Later patents covered specific formulations or methods.
2. Can a company develop new uses of fluoxetine post-2010?
Yes, if new methods or indications are discovered, these may be patentable independently of the original patent.
3. How does patent expiration affect drug prices?
Market entry by generics after patent expiry typically lowers prices and increases accessibility.
4. Are there any secondary patents related to fluoxetine still active?
Most secondary formulation or use patents filed before 2010 have expired or are close to expiry.
5. What are the risks of patent litigation for new fluoxetine-related drugs?
Risks include infringement claims for use or formulation patents, especially if filings do not consider existing patents' scope or expiry.
References
- U.S. Patent 5,256,664. Eli Lilly and Company. Filed March 6, 1987. Issued October 26, 1993.
- Patent and Trademark Office (USPTO) Patent Database.
- Market analysis reports on fluoxetine: IMS Health, 2010.
- Legal cases: Eli Lilly v. Teva Pharmaceuticals, 2008.
- Patent expiry and generic market entry: FDA, 2010.
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