United States Patent 4,112,097: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,112,097, titled "Antihypertensive agents," was issued on September 5, 1978, to the assignee Abbott Laboratories. This patent is significant in the pharmaceutical industry, particularly in the development and marketing of antihypertensive drugs. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this patent.
Background and Invention
The patent describes antihypertensive agents selected from the class consisting of 2[4(tetrahydro-2-furoyl)-piperazino]-4-amino-6,7-dimethoxyquinazoline, specifically terazosin hydrochloride. Terazosin is used in the treatment of hypertension and benign prostatic hyperplasia[2].
Patent Scope
The scope of a patent is defined by its claims, which outline the boundaries of the invention. For US Patent 4,112,097, the claims cover:
- Pharmaceutical Composition: The patent claims a pharmaceutical composition containing terazosin hydrochloride.
- Method of Use: It also claims a method for treating hypertension using this composition[2].
Claims Analysis
The patent includes multiple claims that specify the invention's scope:
- Independent Claims: These claims define the core aspects of the invention, such as the chemical structure of terazosin hydrochloride and its use in treating hypertension.
- Dependent Claims: These claims build upon the independent claims, providing additional details such as specific formulations and dosages.
Independent Claim Length and Count
Research suggests that the length and count of independent claims can be metrics for measuring patent scope. Narrower claims, as seen in this patent, are often associated with a higher probability of grant and a shorter examination process[3].
Patent Landscape
Hatch-Waxman Act
The approval and litigation history of this patent are closely tied to the Hatch-Waxman Act. This act facilitates the approval of generic versions of brand-name drugs by allowing generic manufacturers to file Abbreviated New Drug Applications (ANDAs) with certifications regarding the brand-name drug's patents. For US Patent 4,112,097, the ANDA process played a crucial role in the generic drug approval timeline[1].
Patent Expiration and Litigation
The patent was scheduled to expire on September 5, 1995, but due to the Uruguay Round Agreements Act, Abbott argued for an extension until January 21, 1997. However, the Federal Circuit rejected this argument, confirming the patent's expiration on October 14, 1995[1].
Generic Drug Challenges
Generic drug manufacturers, such as Geneva Pharmaceuticals, filed Paragraph IV certifications challenging the validity of Abbott's patents. These certifications asserted that the patents were invalid or would not be infringed by the generic versions. This led to significant litigation, particularly regarding the '207 patent that protected Form IV terazosin hydrochloride[1].
Impact on the Pharmaceutical Industry
Innovation and Competition
The expiration of US Patent 4,112,097 and the subsequent entry of generic versions of terazosin hydrochloride into the market increased competition and reduced prices for antihypertensive medications. This aligns with the Hatch-Waxman Act's goal of balancing innovation with public access to affordable medications.
Patent Strategy
The patent's history highlights the importance of strategic patent management. Abbott's efforts to extend the patent term and protect different forms of terazosin hydrochloride (e.g., Form IV) demonstrate the complexities and challenges in maintaining patent exclusivity in the pharmaceutical sector.
International Patent Landscape
Global Dossier and Patent Families
The Global Dossier service provided by the USPTO allows users to view the file histories of related applications from participating IP Offices. This service can help in understanding the global patent family for US Patent 4,112,097, including any corresponding patents filed in other countries[4].
Public Access and Search Tools
USPTO Resources
The USPTO offers various resources for searching and analyzing patents, including the Public Search Facility, Patent and Trademark Resource Centers (PTRCs), and the Electronic Official Gazette. These tools are essential for researchers and practitioners to navigate the patent landscape surrounding US Patent 4,112,097[4].
Key Takeaways
- Patent Scope and Claims: US Patent 4,112,097 is defined by its claims covering terazosin hydrochloride and its method of use.
- Hatch-Waxman Act: The patent's approval and generic drug challenges were significantly influenced by the Hatch-Waxman Act.
- Litigation and Expiration: The patent's expiration and subsequent litigation shaped the market entry of generic versions.
- Impact on Industry: The patent's history illustrates the balance between innovation and public access to affordable medications.
- Global Landscape: Understanding the global patent family and using USPTO resources are crucial for navigating the patent landscape.
FAQs
What is the main invention described in US Patent 4,112,097?
The main invention is terazosin hydrochloride, an antihypertensive agent, and its method of use in treating hypertension.
How did the Hatch-Waxman Act influence this patent?
The Hatch-Waxman Act facilitated the approval of generic versions of terazosin hydrochloride by allowing generic manufacturers to file ANDAs with specific certifications regarding the brand-name drug's patents.
What was the outcome of Abbott's argument for patent term extension?
The Federal Circuit rejected Abbott's argument, confirming that the patent expired on October 14, 1995.
How did generic drug manufacturers challenge this patent?
Generic drug manufacturers filed Paragraph IV certifications challenging the validity of Abbott's patents or asserting that the patents would not be infringed by their generic versions.
What resources are available for searching and analyzing patents like US Patent 4,112,097?
The USPTO provides resources such as the Public Search Facility, PTRCs, and the Electronic Official Gazette, along with services like Global Dossier and Common Citation Document.
Sources
- Kaiser v. Abbott Laboratories - [PDF]
- US Patent for Antihypertensive agents - Justia Patents
- Patent Claims and Patent Scope - SSRN
- Search for patents - USPTO - USPTO
- Terazosin crystalline polymorph and pharmaceutical compositions - PubChem
