Details for Patent: 4,536,518

Summary for Patent: 4,536,518

Title:	Antidepressant derivatives of cis-4-phenyl-1,2,3,4-tetrahydro-1-naphthalenamine
Abstract:	Novel cis-isomeric derivatives of 4-phenyl-1,2,3,4-tetrahydro-1-naphthalenamine are useful as antidepressant agents. These novel compounds act to block the synaptosomal uptake of serotonin (5-hydroxy-tryptamine), thereby alleviating serotonin abnormalities at central receptor sites. The preferred embodiment is the enantiomer cis-(1S)-N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthal enamine and its pharmaceutically acceptable acid addition salts.
Inventor(s):	Willard M. Welch, Jr., Charles A. Harbert, B. Kenneth Koe, Allen R. Kraska
Assignee:	Pfizer Corp SRL
Application Number:	US06/090,240
Patent Claim Types: see list of patent claims	Compound; Use; Composition;

Analysis of U.S. Patent 4,536,518 for Piracetam

U.S. Patent 4,536,518, titled "4-oxo-2-pyrrolidineacetamides," was granted on August 20, 1985, to UCB S.A. This patent covers compounds of the formula wherein R is hydrogen or an alkyl group, and R1 is an alkali metal or alkaline earth metal. The primary compound claimed is Piracetam, a nootropic drug. The patent's scope is defined by its claims, which detail the chemical structure and potential uses of the covered compounds. The patent landscape reveals prior art, subsequent developments, and potential infringement considerations.

What is the Scope of U.S. Patent 4,536,518?

The patent's scope is defined by its primary claims concerning specific chemical structures and their therapeutic applications.

What Chemical Structures are Claimed?

The patent claims compounds characterized by the following general formula:

      O
     //
    C - CH2 - N(R1)2
   /
  CH2
 /   \
CH2 - N - R
     \ /
      O

• R: This variable can be hydrogen or an alkyl group. Alkyl groups typically include methyl (-CH3), ethyl (-C2H5), propyl (-C3H7), and so on.
• R1: This variable represents an alkali metal (e.g., Lithium (Li), Sodium (Na), Potassium (K)) or an alkaline earth metal (e.g., Magnesium (Mg), Calcium (Ca)).

The specific compound Piracetam corresponds to this formula where R is hydrogen and R1 is absent or represents the free amine form, as the patent broadly covers the acetamide derivatives and their salts. The patent further specifies that the claim is directed towards these compounds as therapeutically active agents.

What are the Claimed Uses?

The patent asserts that the compounds, including Piracetam, are useful for treating neurological and psychological disorders. Specifically, the abstract mentions applications in improving memory, learning, and central nervous system function. The patent details potential therapeutic uses for conditions such as senile dementia, cerebral insufficiency, and sequelae of cerebrovascular accidents. This broad claim of therapeutic utility forms a significant part of the patent's commercial interest.

What are the Key Exclusions or Limitations?

While the patent broadly claims the chemical structures, it does not explicitly exclude specific derivatives unless they fall outside the defined R and R1 groups. The patent's novelty and inventiveness are presented in contrast to existing chemical compounds and their known therapeutic properties, implying that previously known compounds with different structural features or uses are not covered. The patent's effective lifespan has expired, meaning its claims are no longer in force for exclusive rights.

What is the Patent Landscape for Piracetam and Related Compounds?

The patent landscape for Piracetam is characterized by its early filing date, the expiration of its original patent, and subsequent research and patent filings for related compounds and new uses.

When was the Original Patent Filed and Granted?

• Filing Date: December 27, 1982.
• Grant Date: August 20, 1985.
• Patent Number: U.S. Patent 4,536,518.
• Assignee: UCB S.A.

This filing date places the patent within a period when novel pharmaceutical compounds were actively being patented, and the concept of nootropic agents was gaining traction.

What is the Status of U.S. Patent 4,536,518?

U.S. Patent 4,536,518 has expired. Pharmaceutical patents typically have a term of 20 years from the filing date, subject to potential extensions. Given the 1982 filing date, the patent's exclusivity period ended decades ago.

• Expiration Date (approximate): December 27, 2002 (20 years from filing date).

This expiration means that generic manufacturers can legally produce and market Piracetam without infringing this specific patent.

Have There Been Subsequent Patents for Piracetam?

While the original patent for Piracetam's basic structure and initial uses has expired, research into nootropics has continued. This has led to patents covering:

• New Formulations: Patents may cover specific pharmaceutical compositions designed to improve bioavailability, stability, or delivery of Piracetam.
• New Therapeutic Uses: Research may identify new medical conditions or symptoms that Piracetam can effectively treat, leading to patents for these specific applications.
• Analogues and Derivatives: Significant patent activity exists for compounds structurally related to Piracetam, often referred to as racetams. These analogues aim to improve efficacy, reduce side effects, or target different neurological pathways. Examples include:
  • Aniracetam: Patented for its anxiolytic and cognitive-enhancing properties.
  • Oxiracetam: Patented for its potential in treating cognitive deficits.
  • Pramiracetam: Patented for its potent cognitive-enhancing effects.
  • Levetiracetam: A derivative of Piracetam that has achieved significant commercial success as an antiepileptic drug, covered by distinct patents for its therapeutic uses and formulations. UCB Pharma, the original assignee of U.S. Patent 4,536,518, also holds key patents related to Levetiracetam.

What is the Competitive Landscape for Piracetam?

The competitive landscape for Piracetam is multifaceted due to its expired patent status and the existence of numerous related compounds.

• Generic Competition: Piracetam is widely available as a generic medication in many countries, particularly in Europe and Asia, where it is prescribed for various neurological conditions. Its accessibility as a generic has led to lower pricing and widespread use.
• Over-the-Counter (OTC) Availability: In some regions, Piracetam is available as a dietary supplement or an OTC drug. This is often due to varying regulatory classifications regarding its therapeutic claims and approved indications.
• Analogues and Next-Generation Nootropics: The market for cognitive enhancers includes a vast array of compounds, some of which are direct analogues of Piracetam and others that are entirely different chemical classes. These newer agents, often protected by current patents, compete by offering potentially greater efficacy, targeted mechanisms of action, or improved safety profiles. Examples include various racetam derivatives, noopept, and modafinil.
• Regulatory Status: The regulatory status of Piracetam varies significantly by country. In the United States, Piracetam is not FDA-approved for any medical condition and is not available by prescription. It is available in the US primarily as a research chemical or a dietary supplement, leading to different market dynamics compared to regions where it is a regulated pharmaceutical. This lack of FDA approval limits its prescription-based market in the US.

What is the Significance of UCB S.A.'s Role?

UCB S.A. was the original assignee of U.S. Patent 4,536,518. This places UCB at the forefront of early Piracetam research and patenting. While the patent for Piracetam itself has expired, UCB's continued involvement in pharmaceutical research, particularly in neurology, has led to the development and patenting of other significant drugs, notably Levetiracetam (Keppra®), a successful antiepileptic drug that is also a derivative of Piracetam. UCB’s historical stake in Piracetam highlights its early contributions to the field of central nervous system therapeutics.

What are the Potential Legal and Commercial Implications?

The expiration of U.S. Patent 4,536,518 has significant legal and commercial implications for Piracetam and its market.

What are the Implications of Patent Expiration?

• Market Entry for Generics: The primary implication is the complete freedom for any pharmaceutical company to manufacture, market, and sell Piracetam in the United States without infringing this patent. This has historically led to increased competition and reduced prices for off-patent drugs.
• Freedom to Operate: Companies developing new formulations or combinations involving Piracetam, or researching its use for new indications in the U.S., can do so without seeking licenses for the original compound patent.
• Limited Protection for Original Research: The expiration signifies that the initial investment in discovering and patenting Piracetam has been recouped, and the knowledge is now in the public domain.

Are There Any Other Relevant Patents to Consider?

Despite the expiration of U.S. Patent 4,536,518, other patents may still be relevant for companies operating in the Piracetam space, particularly concerning newer applications or formulations:

• Method of Use Patents: While the basic structure is off-patent, patents for specific new medical uses of Piracetam (e.g., treating a particular subtype of cognitive impairment) could still be in force. If such patents exist and are valid, a company would need a license to market Piracetam for those specific patented uses.
• Formulation Patents: Patents covering novel drug delivery systems, improved stability, or specific dosage forms of Piracetam could restrict competitors from using those particular formulations.
• Process Patents: Patents on specific manufacturing processes that are more efficient or yield higher purity Piracetam might exist. However, process patents are generally harder to enforce and often do not prevent competitors from developing alternative, non-infringing manufacturing methods.
• Patents on Analogues and Derivatives: As mentioned, numerous patents cover compounds structurally similar to Piracetam, such as Levetiracetam. These patents are distinct and protect the specific chemical entities and their uses.

What is the Current Commercial Status of Piracetam in the United States?

Piracetam does not have FDA approval for any indication. This severely limits its commercialization as a prescription drug in the U.S.

• Prescription Status: Piracetam is not an FDA-approved drug. It is not available by prescription in the United States.
• Regulatory Classification: It is typically sold in the U.S. as a dietary supplement or a research chemical. This classification places it outside the purview of traditional pharmaceutical regulation for approved medical uses.
• Market Size: The market for Piracetam in the U.S. is thus primarily within the supplement industry, catering to individuals seeking cognitive enhancement, rather than the prescription pharmaceutical market. The size of this market is difficult to quantify precisely due to its classification.

What are the Opportunities and Risks for New Market Entrants?

For companies considering entering the Piracetam market in the U.S., several opportunities and risks exist.

Opportunities:

• Dietary Supplement Market: The absence of FDA approval for medical use leaves a void that the dietary supplement market can fill. Companies can market Piracetam for general cognitive support, memory enhancement, or focus, provided they comply with FDA regulations for supplements (e.g., DSHEA).
• Niche Markets: There may be opportunities to develop specialized formulations or target specific demographics within the supplement space.
• Research Chemicals: Supplying Piracetam for research purposes remains a viable niche.

Risks:

• Regulatory Scrutiny: The FDA actively monitors the dietary supplement market for products making unsubstantiated health claims or posing safety risks. Companies must ensure their marketing and product labeling comply with all regulations.
• Lack of Medical Validation: Without FDA approval for specific medical conditions, Piracetam cannot be marketed as a treatment for diseases. This limits its perceived value and efficacy claims in a medical context.
• Competition from Other Nootropics: The nootropics market is highly competitive, with a constant influx of new compounds and proprietary blends marketed as cognitive enhancers.
• Safety Concerns and Adverse Events: While generally considered safe, any adverse events associated with Piracetam could lead to increased regulatory attention or negative consumer perception.
• International Market Differences: Companies must be aware that Piracetam is a regulated pharmaceutical in many other countries, with different market dynamics and competitive landscapes.

Key Takeaways

U.S. Patent 4,536,518 for Piracetam, granted to UCB S.A. in 1985, has expired, allowing for generic production. The patent covered specific acetamide derivatives with potential neurological applications. While the original patent is no longer in force, the patent landscape includes patents for related racetam analogues and potential new uses. In the United States, Piracetam is not FDA-approved and is primarily sold as a dietary supplement or research chemical, limiting its commercialization in the prescription pharmaceutical market. Companies can enter the U.S. supplement market but must navigate regulatory compliance and intense competition from other nootropic products.

FAQs

1. Can any company now manufacture and sell Piracetam in the United States?

Yes, because U.S. Patent 4,536,518 has expired, any company can legally manufacture and sell Piracetam in the United States, provided they comply with FDA regulations for dietary supplements or research chemicals.

2. Does the expiration of this patent mean Piracetam is approved by the FDA?

No, patent expiration is separate from regulatory approval. Piracetam remains unapproved by the U.S. Food and Drug Administration (FDA) for any medical indication.

3. What are Racetams, and how are they related to Piracetam?

Racetams are a class of synthetic nootropic drugs that share a common pyrrolidone nucleus, similar to Piracetam, which is the progenitor of this class. Compounds like Aniracetam, Oxiracetam, and Pramiracetam are structural analogues of Piracetam.

4. Are there still any valid patents covering Piracetam in the U.S.?

While the foundational patent for Piracetam's chemical structure and initial uses has expired, there could be patents covering specific new methods of use, novel formulations, or manufacturing processes. These would need to be individually assessed.

5. If Piracetam is not FDA-approved in the U.S., how is it sold?

Piracetam is sold in the U.S. primarily as a dietary supplement or a research chemical. This classification means it is not regulated as a prescription drug and cannot be marketed for the treatment of specific medical conditions.

Citations

[1] UCB S.A. (1985, August 20). 4-oxo-2-pyrrolidineacetamides. U.S. Patent 4,536,518. United States Patent and Trademark Office. [2] Food and Drug Administration. (n.d.). Dietary Supplements. Retrieved from https://www.fda.gov/food/dietary-supplements

Drugs Protected by US Patent 4,536,518

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 4,536,518

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0030081		93C0073	Belgium
European Patent Office	0030081		SPC/GB93/048	United Kingdom
Austria	2668
Australia	517357