United States Patent 8,337,824: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 8,337,824, titled "Linear Polyol Stabilized Polyfluoroacrylate Compositions," is a significant patent in the pharmaceutical industry, particularly in the context of treating hyperkalemia. This patent, assigned to Vifor, covers innovative compositions that include a stabilizing linear polyol and a salt of a crosslinked cation exchange polymer.
Background and Inventors
The patent was invented by a team of researchers including Detlef Albrecht, Michael Burdick, Han-Ting Chang, Dominique Charmot, Ramakrishnan Chidambaram, Eric Connor, Sherin Halfon, I-Zu Huang, Mingjun Liu, Jonathan Mills, and Werner Strüver. It was granted on December 25, 2012, and is set to expire on May 29, 2030[2][4].
Scope of the Patent
Composition Overview
The patent describes compositions that combine a linear polyol with a salt of a crosslinked cation exchange polymer, specifically a polyfluoroacrylate. These compositions are designed to stabilize the polymer, enhancing its performance and shelf life. The linear polyol acts as a stabilizer, preventing degradation and ensuring the polymer remains effective over time[1].
Pharmaceutical Applications
The primary application of these compositions is in the treatment of hyperkalemia, a condition characterized by elevated potassium levels in the blood. The polymer, when stabilized by the linear polyol, can effectively bind potassium ions, helping to reduce their levels in the body. This is particularly relevant for drugs like patiromer sorbitex calcium, which is used to treat hyperkalemia and is bioequivalent to VELTASSA®[2][4].
Claims of the Patent
Key Claims
The patent includes several key claims that define the scope of the invention:
- Claim 1: A composition comprising a linear polyol and a salt of a crosslinked cation exchange polymer, where the polymer includes a fluoro group.
- Claim 2: The composition of claim 1, where the linear polyol is selected from the group consisting of sugar alcohols.
- Claim 3: The composition of claim 1, where the crosslinked cation exchange polymer is a polyfluoroacrylate[1].
Claim Construction and Scope
The claims are constructed to ensure broad coverage while maintaining specificity. The use of terms like "linear polyol" and "crosslinked cation exchange polymer" provides a clear definition of the components involved. The inclusion of specific examples, such as sugar alcohols, further narrows the scope to ensure clarity and prevent overly broad interpretations[3].
Patent Landscape
Related Patents
The patent landscape surrounding US 8,337,824 includes several related patents, also assigned to Vifor, that cover various aspects of potassium-binding agents and their applications:
- US 9,492,476: This patent, titled "Potassium-Binding Agents for Treating Hypertension and Hyperkalemia," expands on the therapeutic uses of these agents.
- US 8147873: Another patent that covers different aspects of the composition and its stabilization[2][4].
Litigation and Generic Challenges
The patent has been subject to litigation, particularly from generic drug manufacturers seeking to market bioequivalent products before the patent's expiration. Companies like Alkem and Ascent have filed ANDAs (Abbreviated New Drug Applications) with the FDA, challenging the validity and infringement of the patent claims. These challenges highlight the ongoing legal battles in the pharmaceutical industry regarding patent protection and generic entry[2].
Impact on Innovation and Patent Quality
Patent Scope and Quality
The debate on patent quality and scope is relevant here. The patent's claims, while specific, have been subject to scrutiny regarding their breadth and clarity. Metrics such as independent claim length and count can be used to assess the patent's scope, with narrower claims generally associated with higher grant probabilities and shorter examination processes[3].
Economic and Regulatory Implications
The patent's expiration in 2030 will have significant economic and regulatory implications. Generic versions of the drug could enter the market, potentially reducing costs and increasing accessibility. However, the ongoing litigation and challenges to the patent's validity may delay or complicate this process[2][4].
Industry Expert Insights
Industry experts emphasize the importance of clear and specific patent claims to avoid litigation and ensure innovation. For example, Robert Kimble, a patent expert, notes that "narrower claims at publication are associated with a higher probability of grant and a shorter examination process than broader claims"[3].
Statistics and Market Impact
- Market Size: The market for hyperkalemia treatments is significant, with an estimated global value projected to grow substantially by 2025.
- Generic Entry: The entry of generic versions could reduce the market share of branded drugs like VELTASSA®, potentially saving millions in healthcare costs annually[4].
Key Takeaways
- Composition and Stabilization: The patent covers compositions of linear polyols and crosslinked cation exchange polymers, specifically polyfluoroacrylates, for treating hyperkalemia.
- Pharmaceutical Applications: The primary application is in binding potassium ions to treat hyperkalemia.
- Litigation and Challenges: The patent faces challenges from generic manufacturers, highlighting ongoing legal battles in the pharmaceutical industry.
- Impact on Innovation: The patent's scope and quality are crucial for innovation, with narrower claims generally preferred for clarity and grant probabilities.
- Economic Implications: The patent's expiration will have significant economic and regulatory implications, potentially leading to increased accessibility and reduced costs.
FAQs
What is the primary application of the compositions described in US 8,337,824?
The primary application is in the treatment of hyperkalemia, a condition characterized by elevated potassium levels in the blood.
Who are the inventors of US 8,337,824?
The inventors include Detlef Albrecht, Michael Burdick, Han-Ting Chang, Dominique Charmot, Ramakrishnan Chidambaram, Eric Connor, Sherin Halfon, I-Zu Huang, Mingjun Liu, Jonathan Mills, and Werner Strüver.
What is the role of the linear polyol in the composition?
The linear polyol acts as a stabilizer, preventing the degradation of the crosslinked cation exchange polymer and ensuring its effectiveness over time.
What are the key claims of the patent?
The key claims include the composition comprising a linear polyol and a salt of a crosslinked cation exchange polymer, with specific examples such as sugar alcohols.
When is the patent set to expire?
The patent is set to expire on May 29, 2030.
Sources
- US8337824B2 - Linear polyol stabilized polyfluoroacrylate compositions - Google Patents
- in the united states district court - RPX Insight
- Patent Claims and Patent Scope - Hoover Institution
- Patiromer: Uses, Interactions, Mechanism of Action - DrugBank Online
