Federal Circuit: Claim Construction Missteps Can Be Fatal for Preliminary Injunctions

In a decision that should make every patent litigator pause before filing for preliminary relief, the Federal Circuit has vacated a preliminary injunction in FMC Corp. v. Sharda USA, LLC, No. 2024-2335 after finding that the district court’s claim construction was legally flawed and improperly influenced its invalidity analysis.

The assertions involving claim construction at the preliminary injunction stage can be perilous, and plaintiffs must be prepared to defend their patents under multiple possible interpretations. It can also be expensive—the Federal Circuit ordered FMC, who originally obtained the injunction, to pay Sharda’s costs to appeal because none of FMC’s arguments held merit.

This is a cautionary tale to movants who should be mindful that they cannot rely on district courts’ rulings in their favor to immunize them from potential sanctions. They should review their positions critically and not just for how they may be received by a court, especially a court not experienced with the substance of the law at issue in the matter.

Why This Matters

Preliminary injunctions are powerful tools—but they come with a high burden. Plaintiffs must show a likelihood of success on the merits, and defendants need only raise a “substantial question” of invalidity to defeat the motion. In FMC v. Sharda, the district court’s narrow construction of the term “composition” (limited to “stable compositions”) was based on disclosures in a provisional application and a related patent—not the asserted patents themselves. The Federal Circuit found this approach improper, emphasizing that: “The ’979 provisional application … cannot limit ‘composition’ in the asserted patents to only stable compositions.”

This error had cascading effects. The district court’s anticipation and obviousness analyses were both tainted by the flawed construction, leading to an abuse of discretion in granting the injunction. 

Key Lesson for Litigants Seeking Preliminary Injunctions

Invalidity defenses need only raise doubt. Defendants do not need to prove invalidity outright. A credible anticipation or obviousness argument—especially when claim construction is open to interpretation—can defeat injunctive relief.

Bottom Line

This decision reinforces that preliminary injunctions in patent cases are not granted lightly. Plaintiffs must ensure their claim construction is defensible and aligned with the actual patent language. Defendants, meanwhile, should focus on raising substantial invalidity questions early—especially if the plaintiff’s interpretation relies on extrinsic or deleted material.

This document is intended to provide you with general information regarding FMC Corp. v. Sharda USA, LLC. The contents of this document are not intended to provide specific legal advice. If you have any questions about the contents of this document or if you need legal advice as to an issue, please contact the attorneys listed or your regular Brownstein Hyatt Farber Schreck, LLP attorney. This communication may be considered advertising in some jurisdictions. The information in this article is accurate as of the publication date. Because the law in this area is changing rapidly, and insights are not automatically updated, continued accuracy cannot be guaranteed.