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Last Updated: February 7, 2025

Details for Patent: 5,753,706


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Summary for Patent: 5,753,706
Title: Methods for treating renal failure
Abstract:Methods of controlling phosphate metabolism and metabolic acidosis in patients suffering from renal failure and associated hyperphosphatemia or patients predisposed to development of a hyperphosphatemic condition are provided. The method in accordance with this invention comprises administering to a patient a ferric-containing compound selected from the group consisting of ferric citrate, ferric acetate, and combinations thereof. Therapeutic benefit can be realized in accordance with such method by administering the compound orally to a patient to contact and bind with ingested phosphate in the patient's digestive tract, and thereby prevent its intestinal absorption.
Inventor(s): Hsu; Chen Hsing (Ann Harbor, MI)
Assignee:
Application Number:08/794,328
Patent Claim Types:
see list of patent claims
Use; Composition; Dosage form;
Patent landscape, scope, and claims:

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

  1. European Patent Specification: Pharmaceutical-grade ferric citrate for medical use[1].
  2. United States Judicial Panel on Multidistrict Litigation: AURYXIA (FERRIC CITRATE) PATENT LITIGATION MDL No. 2896[2].
  3. Google Patents: Ferric citrate dosage forms[4].
  4. Google Patents: Pharmaceutical-grade ferric citrate[5].

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Drugs Protected by US Patent 5,753,706

Applicant Tradename Generic Name Dosage NDA Approval Date TE Type RLD RS Patent No. Patent Expiration Product Substance Delist Req. Patented / Exclusive Use Submissiondate
>Applicant >Tradename >Generic Name >Dosage >NDA >Approval Date >TE >Type >RLD >RS >Patent No. >Patent Expiration >Product >Substance >Delist Req. >Patented / Exclusive Use >Submissiondate

International Family Members for US Patent 5,753,706

Country Patent Number Estimated Expiration Supplementary Protection Certificate SPC Country SPC Expiration
Austria 400264 ⤷  Try for Free
Australia 5441998 ⤷  Try for Free
Australia 723091 ⤷  Try for Free
Canada 2272711 ⤷  Try for Free
Germany 69738824 ⤷  Try for Free
Denmark 0959878 ⤷  Try for Free
European Patent Office 0959878 ⤷  Try for Free
>Country >Patent Number >Estimated Expiration >Supplementary Protection Certificate >SPC Country >SPC Expiration

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