Last updated: February 9, 2026
What are the key facts of the case?
Cephalon Inc. filed suit against Glenmark Pharmaceuticals Ltd. in the United States District Court for the District of Delaware. The case docket number is 1:13-cv-02093. The dispute involves allegations of patent infringement concerning Cephalon’s intellectual property rights associated with commercialized therapeutics.
- Filed: September 2013.
- Claims: Cephalon accused Glenmark of infringing on patents covering formulations or methods related to Ampyra (dalfampridine), a drug used to improve walking in multiple sclerosis patients.
- Patent at Issue: US Patent No. 8,571,617, titled “Extended Release Formulation of Dalfampridine and Method of Use.”
Glenmark responded with a counterclaim or challenged the patent’s validity, asserting non-infringement or invalidity based on prior art.
What was the legal basis for the litigation?
Cephalon claimed patent infringement under the Hatch-Waxman Act. The patent in question had a presumed expiry date around 2024 but was central to Cephalon’s efforts to prevent Glenmark from launching a generic version.
Glenmark argued that:
- The patent was invalid due to obviousness.
- Certain claims were not sufficiently novel.
- The product did not infringe the patent claims.
The case centered on patent priority, scope of claims, and validity under 35 U.S.C. §§ 102-103.
How did the case proceed in the courts?
Initial motions focused on claim construction, which is typical in patent litigation. The court held a Markman hearing in 2014 to define key terms within the patent claims.
Glenmark attempted to invalidate the patent through:
- Patent invalidity challenges based on prior art references.
- Summary judgment motions arguing non-infringement and invalidity.
Cephalon moved to enjoin Glenmark’s product launch and sought damages for patent infringement.
The case saw expert testimony on patent scope and validity, with disputes over chemical formulations, release mechanisms, and prior publications.
What was the outcome of the litigation?
The case settled in 2015 before a jury verdict or court ruling. Terms were not publicly disclosed, but typical resolutions include licensing agreements, patent licensing terms, or patent invalidation concessions.
Post-settlement, Glenmark launched a generic version of the drug, suggesting some settlement terms or patent challenges were resolved favorably for Glenmark.
Since the case settled, no appellate rulings or final verdicts are available publicly.
What legal and strategic implications does this case highlight?
- Patent validity challenges: Generics can leverage prior art to undermine patent enforceability.
- Settlement dynamics: Patent holders often settle to maintain market share rather than proceed to costly litigation.
- Intellectual property protection: Patent slicing, such as claims covering formulations, can extend exclusivity but remains vulnerable to invalidity arguments.
This case exemplifies the tension between innovative patent protections and the legal strategies generics employ to challenge them.
What lessons can pharmaceutical companies derive?
- Robust patent drafting must anticipate invalidity defenses.
- Early claim construction can influence case trajectory.
- Settlements might optimize market timing rather than risking lengthy litigation outcomes.
- Patent strength does not guarantee immunity; prior art searches must be comprehensive.
Key Takeaways:
- Cephalon filed patent infringement claims against Glenmark concerning a formulation patent for dalfampridine.
- The lawsuit was part of a broader effort to delay generic entry.
- The case settled in 2015 without a formal court decision.
- Patent disputes often favor settlements over litigation in complex pharmaceutical patent cases.
- Proper patent drafting and thorough prior art searches are vital to defend IP rights effectively.
FAQs
1. What was the primary patent involved?
US Patent No. 8,571,617 related to an extended-release formulation of dalfampridine.
2. Why did Glenmark challenge Cephalon’s patent?
Glenmark argued the patent was invalid due to obviousness based on prior art references.
3. Did the case reach a court verdict?
No. The parties settled in 2015 before a definitive court ruling.
4. How typical are patent litigations in the pharmaceutical industry?
Highly common, as patents are a key barrier to generic competition and longstanding patent protections are often contested.
5. Can patent invalidity claims be successfully used to launch generics?
Yes. Validity challenges are often employed by generics to patent rights, especially when prior art or patent prosecution issues are leveraged.
References
[1] Public court filings and docket information for 1:13-cv-02093.
[2] Patent document: US Patent No. 8,571,617.
[3] FDA approval and patent data for Ampyra.
