Last updated: March 4, 2026
What are the case details?
Fresenius Kabi USA, LLC filed a patent infringement lawsuit against Custopharm, Inc. in the U.S. District Court for the Western District of Texas (case number 6:21-cv-00286). The litigation centers on allegations that Custopharm infringed two patents held by Fresenius Kabi related to sterile drug formulations.
Key details:
- Filed date: March 3, 2021
- Patents involved: U.S. Patent Nos. 10,664,183 and 10,776,796
- Technology focus: Methods of sterilizing and maintaining stability of parenteral drug formulations.
- Remedy sought: Injunctive relief, damages, and royalties.
What are the patents at issue?
Patent 10,664,183
- Title: "Methods of sterilizing and stabilizing high-concentration drug formulations"
- Issue date: May 26, 2020
- Claims: Cover specific sterilization techniques for high-concentration infusates, including heat and filtration steps.
Patent 10,776,796
- Title: "Stable liquid compositions of pharmaceuticals"
- Issue date: September 15, 2020
- Claims: Encompass compositions with particular pH ranges, buffering agents, and stabilizing excipients for infusion solutions.
Allegations and Legal claims
Fresenius Kabi alleges that Custopharm's generic drug products infringe these patents by employing sterilization and formulation methods protected by the patents. The complaint asserts that Custopharm's products "do not avoid infringement" and have misappropriated proprietary technology.
Legal claims include:
- Patent infringement under 35 U.S.C. § 271
- Willful infringement, seeking enhanced damages
Custopharm denies infringement, asserting that its formulations do not incorporate the patented features and that the patents are invalid for lack of novelty and obviousness.
Case progression and current status
- Initial pleadings: Filed in March 2021, with Custopharm asserting defenses and challenging the patents' validity.
- District court actions: Discovery disputes, including subpoena enforcement and claim construction hearings, occurred over 2022.
- Recent developments: As of early 2023, the case remains in the pre-trial phase. Fresenius Kabi submitted a motion for summary judgment on infringement, which the court has not yet ruled on.
Market implications
This litigation reflects ongoing patent disputes in the sterile injectables sector, where Fresenius Kabi aims to defend its formulations against generic challengers. A court ruling favoring Fresenius Kabi could delay generic entry, affecting pricing and availability.
Comparative analysis with industry standards
Patent assertions in biologic and sterile drug formulations focus on sterilization methods and stability features. Custopharm's defense likely hinges on establishing differences in formulation parameters or non-infringement based on claim construction. Prior litigation in similar cases (e.g., Mylan v. Teva) underscores the importance of clear claim interpretation and proof of patent validity.
Key Points Summary:
| Aspect |
Details |
| Case number |
6:21-cv-00286 |
| Filing date |
March 3, 2021 |
| Patents |
10,664,183; 10,776,796 |
| Allegations |
Infringement of sterilization and stability patents |
| Court |
U.S. District Court, Western District of Texas |
| Status |
Pending resolution; motion for summary judgment filed |
Key Takeaways
- The case reflects standard patent enforcement strategies in sterile drug formulations.
- Validity challenges and claim construction disputes are central to potential outcomes.
- Enforcement of patents related to sterilization methods remains critical for protecting market share.
- Resolution could influence the timeline for generic drug launches in high-concentration infusion markets.
FAQs
-
What are the primary legal issues in this case?
The infringement of patents related to sterilization techniques and formulation stability, along with validity challenges.
-
How does this case compare to other patent litigations in sterile pharmaceuticals?
Similar cases often hinge on claim interpretation and breakthroughs in sterilization methods, impacting market entry.
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What are the possible outcomes?
The court could find for Fresenius Kabi, blocking generic entry, or for Custopharm, invalidating patents or dismissing infringement claims.
-
When could a final decision be expected?
Given procedural timelines, a summary judgment or trial verdict may occur within 1-2 years from now.
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How might this case affect the sterile drugs market?
A ruling in favor of Fresenius Kabi could extend patent exclusivity, delaying generics and maintaining higher prices.
References
- Fresenius Kabi USA, LLC v. Custopharm, Inc., 6:21-cv-00286 (W.D. Texas, 2021).
- U.S. Patent No. 10,664,183 (2020).
- U.S. Patent No. 10,776,796 (2020).
