United States Patent 5,196,444: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 5,196,444, titled "1-(Cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate and compositions and methods of pharmaceutical use thereof," is a significant patent in the pharmaceutical industry. This patent, granted to Takeda Chemical Industries Ltd., covers the compound known as candesartan cilexetil, marketed under the trade name ATACAND.
Background of the Patent
The patent was granted on March 23, 1993, and it describes a novel compound and its pharmaceutical compositions, which are potent angiotensin II antagonists. These compounds are valuable in treating various circulatory system diseases, including hypertension, heart diseases, strokes, cerebral diseases, and nephritis[1][2].
Scope of the Patent
Chemical Composition
The patent details the chemical structure and synthesis of 1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate. This compound is produced through a specific esterification process involving cyclohexyl 1-iodoethyl carbonate and 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid[1].
Pharmaceutical Use
The patent claims the use of this compound and its pharmaceutical compositions for treating circulatory diseases. The compositions include the active compound and a pharmaceutically acceptable carrier, making them suitable for various therapeutic applications[1].
Stereochemical Forms
The patent also covers the mixture of isomers and individual stereoisomers of the compound, including geometrical isomers, rotational isomers, enantiomers, racemates, and diastereomers. This comprehensive coverage ensures that all possible forms of the compound are protected under the patent[1].
Claims of the Patent
Compound Claims
The patent claims the novel compound itself, its pharmaceutically acceptable salts, and the process for preparing these compounds. The claims are specific to the chemical structure and the method of synthesis, ensuring that any identical or substantially similar compounds would infringe on this patent[1].
Composition Claims
The patent also claims pharmaceutical compositions that include the active compound and a pharmaceutically acceptable carrier. These compositions are designed for treating various circulatory diseases, and the claims cover different formulations and methods of administration[1].
Method Claims
The patent includes method claims for treating circulatory system diseases by administering an effective amount of the compound or its pharmaceutical compositions. These method claims are crucial as they protect the therapeutic use of the compound, which is a key aspect of its commercial value[1].
Patent Landscape and Legal Considerations
Patent Term Extension
The patent was eligible for a patent term extension under 35 U.S.C. § 156 due to the regulatory review period by the FDA. The extension was calculated to be 413 days, extending the patent's expiration date from April 18, 2011, to June 4, 2012[2].
Genus Claims and Patent Scope
The patent's scope is influenced by the broader context of genus claims in pharmaceutical patents. Genus claims aim to capture a class of compounds rather than specific embodiments. However, these claims must be supported by a written description and enablement requirements as per 35 U.S.C. § 112(a). The Federal Circuit's jurisprudence on genus claims has made it challenging for pharmaceutical and biotechnology companies to obtain broad patent protection without detailed disclosure of all species within the genus[3].
Regulatory and Legal Implications
The patent's validity and scope are subject to regulatory and legal scrutiny. The FDA's approval process and the subsequent patent term extension highlight the interplay between regulatory approval and patent protection. Any challenges or disputes regarding the patent's scope or claims would be adjudicated based on the written description, enablement, and other statutory requirements[2][3].
Impact on the Pharmaceutical Industry
Market Dominance
The patent on candesartan cilexetil has allowed Takeda Chemical Industries Ltd. to maintain market dominance in the treatment of hypertension and related circulatory diseases. The exclusive rights granted by the patent have enabled the company to recoup its investment in research and development[2].
Innovation and Competition
The patent landscape in the pharmaceutical industry is complex, with broad genus claims often being a double-edged sword. While they provide broad protection, they also require extensive disclosure and can be vulnerable to challenges. This dynamic influences innovation and competition, as companies must balance the need for broad protection with the risk of invalidation due to insufficient disclosure[3].
Production and Manufacturing
One-Pot Process
Recent developments include more efficient methods for producing candesartan, such as the one-pot process described in later patents. These advancements simplify the manufacturing process and reduce costs, making the drug more accessible and affordable[5].
Conclusion
United States Patent 5,196,444 is a pivotal patent in the pharmaceutical industry, covering the compound candesartan cilexetil and its therapeutic applications. The patent's scope, claims, and legal considerations highlight the complexities of patent protection in the pharmaceutical sector. Understanding these aspects is crucial for companies navigating the patent landscape and for innovators seeking to develop new treatments.
Key Takeaways
- Compound and Composition: The patent covers the novel compound 1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate and its pharmaceutical compositions.
- Therapeutic Use: The compound is used to treat circulatory system diseases, including hypertension and heart diseases.
- Patent Term Extension: The patent was extended by 413 days due to regulatory review.
- Genus Claims: The patent's scope is influenced by genus claims, which require detailed disclosure and enablement.
- Impact on Industry: The patent has allowed Takeda Chemical Industries Ltd. to maintain market dominance and has influenced innovation and competition in the pharmaceutical industry.
FAQs
What is the main compound covered by United States Patent 5,196,444?
The main compound is 1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate, known as candesartan cilexetil.
What are the therapeutic applications of the compound?
The compound is used to treat circulatory system diseases such as hypertension, heart diseases, strokes, cerebral diseases, and nephritis.
Why was the patent term extended?
The patent term was extended by 413 days due to the regulatory review period by the FDA, as per 35 U.S.C. § 156.
What are genus claims in the context of pharmaceutical patents?
Genus claims aim to capture a class of compounds rather than specific embodiments, but they must be supported by a written description and enablement requirements.
How has the patent impacted the pharmaceutical industry?
The patent has allowed Takeda Chemical Industries Ltd. to maintain market dominance in the treatment of hypertension and related diseases, influencing innovation and competition in the industry.
Sources
- US5196444A - 1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate and compositions and methods of pharmaceutical use thereof - Google Patents.
- USPTO - NOTICE OF FINAL DETERMINATION - USPTO.
- DigitalCommons@NYLS - Eviscerating Patent Scope - DigitalCommons@NYLS.
- Google Patents - One pot process for the preparation of candesartan - Google Patents.
