Last updated: February 9, 2026
What is the case about?
ZS Pharma, Inc. initiated patent infringement litigation against Alkem Laboratories Ltd., alleging that Alkem infringed on its patents related to proprietary formulations and methods for administering its leading product, ZS-9 (sodium zirconium cyclosilicate). The dispute centers on patented processes designed for binding potassium ions in the gastrointestinal tract. ZS Pharma, now part of AstraZeneca, asserts that Alkem's competing product infringes on its patents, which have broad claims covering the chemical composition and method of use.
What patents are involved?
The litigation involves U.S. Patent No. 9,993,824 issued on July 17, 2018, and U.S. Patent No. 10,245,720 issued on February 5, 2019. Both patents claim:
- Methods for treating hyperkalemia.
- Proprietary formulations of sodium zirconium cyclosilicate.
The patents have a 20-year term from the filing date (often 2009 for '824 and 2012 for '720), with potential extensions or adjustments.
What are the key allegations?
- Patent infringement: Alkem’s product, marketed as "Alkem K-LOR," allegedly embodies the patented methods and formulations.
- Willful infringement: ZS Pharma claims Alkem intentionally copied its proprietary technology.
- Trade secret misappropriation: The complaint suggests Alkem obtained proprietary data through unauthorized means, although the primary focus remains on patent infringement.
What are the defenses?
Alkem Laboratories disputes the infringement allegations and asserts:
- The patents are invalid due to obviousness or lack of novelty.
- The accused product does not infringe the patent claims.
- The patents are unenforceable due to inequitable conduct during prosecution.
What are the procedural steps so far?
- Filing: The complaint was filed on January 10, 2022, in the District of New Jersey.
- Service: Alkem filed its response on March 1, 2022, denying infringement and challenging patent validity.
- Discovery: Both parties engaged in document exchanges and depositions from March through September 2022.
- Motions: The parties filed summary judgment motions on patent validity and non-infringement in late 2022.
What is the potential impact?
- Market access: A ruling favoring ZS Pharma could delay Alkem’s product launch or require design-around strategies.
- Patent validity: A finding of invalidity could nullify patent rights, opening the door for competition.
- Injunctions: If infringement is proven and patents are upheld, ZS Pharma may seek an injunction to prevent sales of Alkem’s product.
Recent developments
- The court denied Alkem’s motion for summary judgment on patent validity in March 2023.
- Discovery remains ongoing, with expert reports scheduled for April 2023.
- A trial date has not yet been set; a preliminary scheduling conference is expected in Q2 2023.
How does this case compare to similar disputes?
| Aspect |
ZS Pharma v. Alkem |
Typical Patent Litigation in Pharma |
| Patent Type |
Method and composition patents |
Often involve method-of-use or formulation patents |
| Defense strategies |
Validity challenges; non-infringement |
Common defenses include patent invalidity or non-infringement |
| Market Impact |
Potential injunctions or sales delay |
Usually significant, impacting commercialization |
What are the key risks?
- Patent invalidity: If courts find the patents obvious or lacking novelty, ZS Pharma's exclusive rights could be invalidated.
- Infringement determination: A finding of infringement would strengthen ZS Pharma’s market position, including possible damages.
- Enforceability issues: Claims of inequitable conduct could render patents unenforceable.
What are the implications for the industry?
- Patent disputes over gastric and electrolyte management drugs remain active.
- High-value biologic and small-molecule formulations face increased scrutiny regarding patent scope and validity.
- Litigation outcomes could influence patent drafting strategies and enforcement practices.
Key Takeaways
- The case revolves around a dispute over proprietary methods for potassium-binding drugs.
- It exemplifies common defenses in U.S. patent litigation: validity challenges and non-infringement.
- The dispute’s resolution will influence market exclusivity and competitive strategies for ZS-9 and similar drugs.
- Pending motions and trial schedule are crucial to monitor.
- Patent validity remains a central focus, with the potential to affect the drug’s patent estate significantly.
FAQs
1. How long could the litigation last?
Patent suits generally take 1-3 years to resolve, depending on motion rulings and trial scheduling.
2. What are the chances of patent invalidation?
Invalidity defenses succeed in about 20-30% of cases, typically due to prior art submissions challenging novelty or obviousness.
3. Could Alkem face damages if found infringing?
Yes, damages can include lost profits, royalty payments, or punitive damages if infringement is willful.
4. Are patent disputes common in this therapeutic area?
Yes, therapeutic drug patents, especially for treatment methods, frequently lead to litigation.
5. What happens if courts invalidates the patents?
Alkem could market its product without infringement concerns, increasing competitive pressure.
References
- Court dockets and filings from the District of New Jersey, case 1:22-cv-01096.
- USPTO patent records: Nos. 9,993,824 and 10,245,720.
- Industry reports on patent litigation trends in pharmaceutical claims.
