Duke University v. Sandoz Inc., Appeal No. 2024-1078 (Fed. Cir. Nov. 18, 2025)

This week, the Federal Circuit reversed a district court’s denial of judgment as a matter of law for Sandoz Inc., finding that a claim of Duke University and Allergan Sales, LLC’s (collectively, “Allergan”) U.S. Patent No. 9,579,270 is invalid for lack of adequate written description. The ’270 patent claims formulations for treating hair loss, and the Court concluded that any reasonable juror would have found, by clear and convincing evidence, that a person of ordinary skill in the art reviewing the patent would be unable to visualize or recognize members of the claimed subgenus of chemical compounds.

The ’270 patent describes a method for growing hair by topically applying a chemical compound known as prostaglandin. Allergan markets Latisse, an FDA-approved topical solution for treating eyelash hair loss. Sandoz manufactures and sells a generic version of Latisse. In 2018, Allergan sued Sandoz, alleging its generic drug product infringed claim 30 of the ‘270 patent. Sandoz stipulated to infringement but challenged the validity of the claim. After a five-day jury trial, the jury found that Sandoz had failed to prove that claim 30 was invalid for obviousness, lack of enablement, or lack of adequate written description, and awarded Allergan $39 million in infringement damages. Sandoz filed a motion for a new trial and for judgment as a matter of law (“JMOL”), both of which the district court denied. This appeal followed.

When a district court denies a motion for JMOL, the Court reviews its decision under the law of that court’s regional circuit – here, the Tenth Circuit. The Tenth Circuit applies de novo review to a district court’s denial of JMOL, thus a district court’s refusal to grant JMOL may be reversed only if the evidence is such that, without weighing the credibility of the witnesses, the only reasonable conclusion is in the moving party’s favor. Whether a patent provides adequate written description for a claim presents a question of fact; namely, whether the patent specification discloses such that a person of ordinary skill in the art would conclude the inventor possessed the full scope of the invention at the time of their patent application. Lack of written description must be established by clear and convincing evidence.

Here, Sandoz argued that the specification of the ‘270 patent is written so broadly that it encompasses a “universe of billions of compounds,” while claim 30 is limited to roughly 1,620 of those potential compounds. Based on the vast discrepancy between the written description and the actual scope of the claim, Sandoz contended, the pertinent artisan would conclude that the named inventors did not actually possess the invention claimed in claim 30. But to meet the written description requirement in this context, a patent must provide sufficient “blaze marks” to direct a skilled artisan to the claimed subgenus. In other words, a specification must “provide adequate direction which reasonably would lead persons skilled in the art to compounds actually claimed in claim 30.”

Based on the evidence introduced at trial, the Court agreed with Sandoz, concluding that no reasonable juror could find anything other than clear and convincing evidence that the ‘270 patent fails to describe either (1) a representative number of species of claim 30’s subgenus or (2) structural features common to all members of that subgenus. The Court concluded that the ‘270 patent discloses, at best “a menu of available atoms, moieties, and functional groups” from which a skilled artisan could populate certain structures. The court analogized the disclosure to a maze, holding that “following such a maze-like path, each step providing multiple alternative paths, is not a written description of what might have been described if each of the optional steps had been set forth as the only option.” Similarly, the Court continued, “one cannot disclose a forest in the original application, and then later pick a tree out of the forest and say ‘here is my invention.’”

Ultimately, the Court reversed the district court’s decision and held that the specification of the ‘270 patent fails to provide the relevant artisan with sufficient blaze marks or structural commonalities among the claimed compounds to lead her to conclude that the inventor actually possessed the claimed invention.  In short, the patent does not “direct one to the proposed tree in particular and does not teach the point at which one should leave the trail to find it.”

The opinion can be found here.

By Julia Davis

This article summarizes aspects of the law and does not constitute legal advice. For legal advice with regard to your situation, you should contact an attorney.