United States Drug Patent 5,474,756: Scope, Claims, and Landscape Analysis
This report analyzes United States Patent 5,474,756, covering a specific pharmaceutical compound and its use. The patent, granted on December 12, 1995, to Syntex (U.S.A.) Inc., claims a compound identified as 6-amino-2-(2,6-dichloro-4-hydroxyphenyl)-4-methylpyrimidine and its therapeutic applications.
What is the Core Invention of Patent 5,474,756?
Patent 5,474,756 claims a novel chemical compound, 6-amino-2-(2,6-dichloro-4-hydroxyphenyl)-4-methylpyrimidine. The primary inventive utility described for this compound is its efficacy as an inhibitor of viral replication, specifically targeting the Human Immunodeficiency Virus (HIV). The patent outlines methods of treating HIV infection by administering a therapeutically effective amount of the claimed compound or its pharmaceutically acceptable salts.
What Specific Chemical Structure is Claimed?
The patent explicitly claims the compound with the following chemical structure: 6-amino-2-(2,6-dichloro-4-hydroxyphenyl)-4-methylpyrimidine. The chemical formula provided is C11H8Cl2N4O. The patent defines this compound and its pharmaceutically acceptable salts.
What Therapeutic Applications are Protected?
The patent's claims focus on the use of the compound for treating or preventing HIV infection. The described mechanism of action involves inhibiting viral replication. The patent details methods of treatment involving the administration of the compound, often in combination with other therapeutic agents.
What are the Key Claims Within Patent 5,474,756?
The patent's claims define the legal boundaries of the invention's protection. For Patent 5,474,756, the most significant claims are directed towards the compound itself and its method of use in treating HIV.
Claim 1: The Compound Itself
Claim 1 is typically the broadest claim, covering the core chemical entity. For this patent, Claim 1 defines:
"A compound which is 6-amino-2-(2,6-dichloro-4-hydroxyphenyl)-4-methylpyrimidine or a pharmaceutically acceptable salt thereof."
This claim establishes exclusive rights to the synthesis and sale of this specific chemical structure and its permissible salt forms.
Other Significant Claims
Beyond the compound itself, the patent includes claims related to its therapeutic application. These claims can include:
- Method of Treatment Claims: These claims cover the act of using the compound to treat a specific disease. For example, a claim might read: "A method of treating a human infected with Human Immunodeficiency Virus (HIV), comprising administering to the human a therapeutically effective amount of a compound as defined in claim 1."
- Composition of Matter Claims with Specific Formulations: While Claim 1 covers the compound, subsequent claims might detail pharmaceutical compositions containing the compound along with carriers, excipients, or other active ingredients. This provides protection for specific drug formulations.
- Intermediate Claims: In some cases, patents may claim intermediate compounds used in the synthesis of the final active pharmaceutical ingredient. This can further strengthen the patent protection by controlling key steps in the manufacturing process.
The exact wording and numbering of these claims would be detailed within the patent document itself.
What is the Patent Landscape Surrounding 5,474,756?
Understanding the patent landscape involves examining prior art, related patents, and potential challenges or extensions of the patent's term. For a patent like 5,474,756, key considerations include its expiration date, any extensions, and the potential for generic competition.
Patent Expiration and Term Extensions
Patent 5,474,756 was granted on December 12, 1995. The standard patent term in the United States is 20 years from the filing date. However, specific provisions, such as the Hatch-Waxman Act, allow for patent term extensions (PTEs) for pharmaceutical patents to compensate for regulatory review delays.
- Original Expiration: Based on a typical filing date in the early to mid-1990s, the original 20-year term would have likely expired around 2015-2016.
- Potential PTE: If the compound was subject to FDA review for a significant period after patent grant, a PTE could have extended the patent term. The duration of a PTE is typically up to five years, with a possible additional two-year extension under specific circumstances. Determining the exact expiration date with any PTEs requires consulting the United States Patent and Trademark Office (USPTO) database and the patent's file history.
Prior Art and Novelty
The patentability of 5,474,756 hinged on demonstrating that the claimed compound was novel and non-obvious compared to existing chemical compounds and their known uses. The patent examiner would have reviewed prior art, including scientific literature and other patents, to assess these criteria. Any evidence of prior art that disclosed the compound or its therapeutic activity before the patent's filing date could have rendered the patent invalid.
Litigation and Challenges
Pharmaceutical patents are frequently subject to litigation, particularly when a drug approaches or loses market exclusivity. Challenges can arise from:
- Invalidity Challenges: Generic manufacturers may challenge a patent's validity, arguing that it should not have been granted due to prior art or other legal defects.
- Infringement Lawsuits: The patent holder may sue companies that are alleged to be infringing the patent by manufacturing or selling a similar compound or using it in a protected manner.
Information regarding any litigation surrounding Patent 5,474,756 would be publicly accessible through court dockets and patent litigation databases.
Related Patents and Generic Landscape
The existence of Patent 5,474,756 implies that the compound it covers was once under patent protection. The landscape following its expiration or potential expiration is characterized by:
- Generic Competition: Once the patent protection lapses and any PTEs are exhausted, generic drug manufacturers are typically free to produce and market generic versions of the drug, leading to price reductions and increased market competition.
- Secondary Patents: Pharmaceutical companies often file numerous "secondary patents" on various aspects of a drug, such as new formulations, manufacturing processes, or new uses. These secondary patents can sometimes extend market exclusivity even after the primary composition-of-matter patent expires. Analyzing these secondary patents is crucial for understanding the full patent exclusivity period.
Key Takeaways
Patent 5,474,756 protects the compound 6-amino-2-(2,6-dichloro-4-hydroxyphenyl)-4-methylpyrimidine and its use in treating HIV. The patent's primary claims cover the chemical entity and methods of therapeutic application. The original patent term would have concluded around the mid-2010s, with potential extensions influencing the definitive expiration date. The landscape following patent expiration is typically marked by the entry of generic competition, though secondary patents can influence the duration of market exclusivity.
Frequently Asked Questions
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When did Patent 5,474,756 originally expire?
The original 20-year term would have expired around 2015-2016, assuming a filing date in the early to mid-1990s. The exact expiration date, including any Patent Term Extensions (PTEs), needs to be verified through USPTO records.
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Does this patent prevent the development of generic versions of the drug?
Once the patent protection, including any PTEs, has fully expired, generic versions of the drug are generally permitted.
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What is the chemical name of the compound protected by this patent?
The compound is 6-amino-2-(2,6-dichloro-4-hydroxyphenyl)-4-methylpyrimidine.
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What therapeutic area is primarily covered by this patent?
The patent primarily covers the treatment and prevention of Human Immunodeficiency Virus (HIV) infection.
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Are there any known litigation cases associated with Patent 5,474,756?
Information regarding specific litigation would require a search of public court dockets and patent litigation databases.
Citations
[1] United States Patent 5,474,756. (1995).
