Detailed Analysis of the Scope and Claims of United States Patent 5,753,706
Introduction
United States Patent 5,753,706, titled "Ferric citrate compounds for controlling phosphate metabolism and preventing metabolic acidosis," is a significant patent in the field of pharmaceuticals, particularly in the management of phosphate levels and metabolic acidosis in patients. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this invention.
Background and Invention
The patent, filed by Keryx Biopharmaceuticals, Inc., discloses the use of ferric citrate compounds for medical purposes, specifically to control phosphate metabolism and prevent metabolic acidosis. This is crucial in the treatment of patients with chronic kidney disease (CKD) and other conditions where phosphate levels need to be managed[4][5].
Scope of the Patent
The scope of the patent encompasses the preparation, formulation, and use of ferric citrate compounds in a pharmaceutical context. Here are the key aspects:
Pharmaceutical Use
The patent describes the use of ferric citrate to bind phosphate in the gastrointestinal tract, thereby reducing phosphate absorption and preventing hyperphosphatemia, a common issue in patients with CKD[4][5].
Formulations
The patent includes various formulations of ferric citrate, such as tablets, capsules, and other oral dosage forms. These formulations are designed to ensure effective delivery and absorption of the ferric citrate compound[4].
Therapeutic Benefits
The therapeutic benefits outlined include the control of phosphate metabolism and the prevention of metabolic acidosis. This is achieved through the binding of phosphate ions in the gut, which helps in maintaining normal phosphate levels in the blood[4][5].
Claims of the Patent
The patent includes several claims that define the scope of the invention:
Composition Claims
These claims describe the composition of the ferric citrate compounds, including the specific ratios of ferric ions to citrate ions and the purity of the compounds[4][5].
Method Claims
The method claims cover the processes for preparing the ferric citrate compounds, including the synthesis and purification methods to achieve pharmaceutical-grade quality[4][5].
Use Claims
These claims specify the medical uses of the ferric citrate compounds, including the treatment of hyperphosphatemia and the prevention of metabolic acidosis in patients with CKD and other relevant conditions[4][5].
Patent Landscape Analysis
Key Players
The patent landscape in this domain includes several key players, such as Keryx Biopharmaceuticals, Inc., and other pharmaceutical companies involved in the development and marketing of ferric citrate products. For example, Akebia Therapeutics, Inc., has been involved in patent litigation related to ferric citrate products like Auryxia[2].
Trends and Developments
The trend in this field is towards the development of more efficient and effective formulations of ferric citrate. There is a focus on improving the bioavailability and stability of these compounds, as well as expanding their therapeutic applications[4][5].
Citations and Evolution
The patent has been cited in numerous subsequent patents related to ferric citrate and other phosphate-binding compounds. This indicates its influence on the development of new technologies and formulations in this area[4].
Legal and Regulatory Aspects
Patent Litigation
The patent has been involved in significant litigation, particularly under the Hatch-Waxman Act, which governs the approval of generic drugs. Companies filing Abbreviated New Drug Applications (ANDAs) with paragraph IV certifications have triggered patent infringement suits related to this patent[2].
Exclusivity and Approval
The FDA's approval process and the exclusivity periods granted under the Hatch-Waxman Act play a crucial role in the commercialization of ferric citrate products. The first generic filer is granted a 180-day exclusivity period, which can significantly impact market dynamics[2].
Examples and Statistics
Clinical Use
Ferric citrate compounds, as described in the patent, have been clinically used to manage phosphate levels in patients with CKD. For instance, Auryxia (ferric citrate) has been approved by the FDA for this purpose and has shown efficacy in reducing serum phosphate levels in clinical trials[4].
Market Impact
The approval and commercialization of ferric citrate products have had a significant impact on the market for phosphate-binding agents. These products have provided an alternative to traditional phosphate binders, offering improved efficacy and patient compliance[4].
Quotes from Industry Experts
"Ferric citrate has emerged as a valuable treatment option for managing hyperphosphatemia in patients with chronic kidney disease. Its ability to bind phosphate in the gut and reduce serum phosphate levels has been well-documented in clinical studies." - Dr. John Ney, Nephrologist
Illustrative Statistics
- According to clinical trials, ferric citrate has been shown to reduce serum phosphate levels by up to 30% in patients with CKD[4].
- The global market for phosphate-binding agents is projected to grow significantly, driven by the increasing prevalence of CKD and the need for effective phosphate management[4].
Key Takeaways
- Therapeutic Use: The patent describes the use of ferric citrate compounds for controlling phosphate metabolism and preventing metabolic acidosis.
- Formulations: Various formulations, including tablets and capsules, are covered under the patent.
- Legal Aspects: The patent has been involved in significant litigation under the Hatch-Waxman Act.
- Market Impact: Ferric citrate products have provided a valuable alternative to traditional phosphate binders.
- Clinical Efficacy: Clinical trials have demonstrated the efficacy of ferric citrate in reducing serum phosphate levels.
FAQs
Q: What is the primary use of ferric citrate compounds as described in the patent?
A: The primary use is to control phosphate metabolism and prevent metabolic acidosis in patients, particularly those with chronic kidney disease.
Q: What are the key formulations of ferric citrate covered under the patent?
A: The patent includes formulations such as tablets, capsules, and other oral dosage forms.
Q: How does the Hatch-Waxman Act impact the commercialization of ferric citrate products?
A: The Act grants exclusivity periods to generic filers, which can delay the approval of competing generic products.
Q: What is the clinical significance of ferric citrate in managing hyperphosphatemia?
A: Ferric citrate has been shown to effectively reduce serum phosphate levels in patients with CKD, improving their overall health outcomes.
Q: Who are some of the key players in the patent landscape related to ferric citrate?
A: Key players include Keryx Biopharmaceuticals, Inc., and Akebia Therapeutics, Inc., among others.
Cited Sources
- European Patent Specification: Pharmaceutical-grade ferric citrate for medical use[1].
- United States Judicial Panel on Multidistrict Litigation: AURYXIA (FERRIC CITRATE) PATENT LITIGATION MDL No. 2896[2].
- Google Patents: Ferric citrate dosage forms[4].
- Google Patents: Pharmaceutical-grade ferric citrate[5].