United States Patent 5,250,542: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 5,250,542, titled "Peripherally selective piperidine carboxylate opioid antagonists," is a significant patent in the pharmaceutical sector, particularly in the area of opioid antagonists. This patent, issued to Eli Lilly and Company, covers compounds and methods related to the treatment of various medical conditions. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this patent.
Background and Invention
The patent, filed on July 17, 1992, and granted on September 21, 1993, describes peripherally selective piperidine carboxylate opioid antagonists. These compounds are designed to relieve symptoms such as idiopathic constipation and irritable bowel syndrome without the central nervous system effects commonly associated with opioid antagonists[4].
Claims and Scope
Independent and Dependent Claims
The patent includes several independent and dependent claims that define the scope of the invention. Independent claims typically outline the broadest aspects of the invention, while dependent claims narrow down the scope by adding specific limitations.
- Independent Claims: These claims define the core invention, including the chemical structure of the piperidine carboxylate opioid antagonists and their use in treating certain medical conditions.
- Dependent Claims: These claims specify various aspects such as the preparation methods, specific compounds, and their therapeutic applications.
Claim Construction
The interpretation of patent claims is crucial for understanding the patent's scope. Claim construction involves analyzing the intrinsic evidence of the patent, including the claims, specification, and prosecution history. The ordinary and customary meaning of a claim term is determined from the perspective of a person of ordinary skill in the art (POSA) at the time of the invention[1].
Prosecution History and Extrinsic Evidence
The prosecution history of a patent, including any amendments, arguments, and responses to office actions, can significantly impact the interpretation of claims. For example, if certain claims were rejected or cancelled during the prosecution process, this can limit the scope of the allowed claims through prosecution disclaimer[1].
Definiteness Requirement
The patent must meet the definiteness requirement, which means that the claims must be precise enough to afford clear notice of what is claimed. This requirement is measured from the viewpoint of a POSA at the time the patent was filed. While a modicum of uncertainty is permitted due to the inherent limitations of language, the claims must still be clear enough for a skilled artisan to discern the boundaries of the claim[1].
Patent Term and Maintenance Fees
The patent term for U.S. patents is generally 20 years from the filing date of the earliest non-provisional application. However, patents can expire earlier if maintenance fees are not paid. For instance, maintenance fees are due at 3.5, 7.5, and 11.5 years after the patent grant date. Failure to pay these fees can result in the patent expiring prematurely[2].
Patent Term Extension
In some cases, patents can be extended under 35 U.S.C. section 156, which allows for the extension of the patent term to compensate for delays in the regulatory approval process. For example, Eli Lilly and Company applied for a patent term extension for U.S. Patent Nos. 5,250,542 and 5,434,171 due to the lengthy regulatory review period for the drug product alvimopan (Entereg)[5].
Regulatory Review Period
The regulatory review period for Entereg, the human drug product claimed by the patents, was significant. The total length of the regulatory review period was 5,305 days, with 3,879 days occurring during the testing phase and 1,426 days during the FDA approval phase. This extended period can justify a patent term extension to ensure the patent holder has sufficient time to recoup their investment[5].
Patent Landscape
Prior Art and Related Patents
The patent landscape includes prior art and related patents that can influence the scope and validity of the patent. For instance, the patent application for U.S. Patent 5,250,542 was originally rejected based on prior references such as U.S. Patent No. 5,250,542 itself being cited in later patent applications and litigations[1].
Litigation and Enforcement
Patents like U.S. Patent 5,250,542 can be involved in litigation to enforce their claims or defend against allegations of infringement. The interpretation of claims and the determination of their scope are critical in such legal proceedings. For example, the concept of prosecution disclaimer and the definiteness requirement play significant roles in patent litigation[1].
Economic and Research Implications
Patent Claims Research Dataset
The USPTO's Patent Claims Research Dataset provides detailed information on claims from U.S. patents, including those related to pharmaceuticals. This dataset can be used to analyze trends and measurements of patent scope, offering insights into the strategic use of patents in the pharmaceutical industry[3].
Industry Impact
Patents like U.S. Patent 5,250,542 have a significant impact on the pharmaceutical industry. They protect innovative compounds and methods, allowing companies to invest in research and development with the assurance of exclusive rights. This protection is crucial for the development of new treatments and therapies.
Key Takeaways
- Scope and Claims: The patent covers peripherally selective piperidine carboxylate opioid antagonists and their therapeutic applications.
- Claim Construction: Claims are interpreted based on the intrinsic evidence and the perspective of a POSA.
- Prosecution History: The prosecution history, including any amendments and rejections, influences the claim scope.
- Definiteness Requirement: Claims must be clear and precise to afford notice of what is claimed.
- Patent Term and Maintenance Fees: Patents expire after 20 years or earlier if maintenance fees are not paid.
- Regulatory Review Period: The patent term can be extended due to lengthy regulatory approval processes.
- Patent Landscape: Prior art, related patents, and litigation can affect the patent's scope and validity.
Frequently Asked Questions (FAQs)
What is the main subject of U.S. Patent 5,250,542?
U.S. Patent 5,250,542 covers peripherally selective piperidine carboxylate opioid antagonists, which are used to treat conditions such as idiopathic constipation and irritable bowel syndrome.
How are patent claims interpreted?
Patent claims are interpreted based on the intrinsic evidence of the patent, including the claims, specification, and prosecution history, from the perspective of a person of ordinary skill in the art (POSA) at the time of the invention.
What is the definiteness requirement for patent claims?
The definiteness requirement mandates that patent claims must be precise enough to afford clear notice of what is claimed, measured from the viewpoint of a POSA at the time the patent was filed.
Can the patent term be extended?
Yes, the patent term can be extended under 35 U.S.C. section 156 to compensate for delays in the regulatory approval process.
What happens if maintenance fees are not paid?
If maintenance fees are not paid, the patent can expire prematurely, regardless of the remaining term.
Cited Sources
- Merck Sharp & Dohme Corp. v. Teva Pharms. U.S., Inc. - Casetext
- Patent and Trademark Office Notices - USPTO
- Patent Claims Research Dataset - USPTO
- US5250542A - Peripherally selective piperidine carboxylate opioid antagonists - Google Patents
- Application for Patent Term Extension for U.S. Patent Nos. 5,250,542 and 5,434,171 - FDA
