IP Law Daily, PATENT—Fed. Cir.: Jury verdict of $39M over eyelash hair growth patent vacated, (Nov 18, 2025)

By Brian Craig, J.D.

No reasonable juror could have found that the generic drug manufacturer failed to prove that the patent claim lacks an adequate written description.

Concluding that a patent that describes a method to promote eyelash hair growth is invalid, the U.S. Court of Appeals for the Federal Circuit has vacated a $39 million jury verdict in an infringement suit brought by Duke University and Allergan Sales, LLC against generic drug manufacturer Sandoz Inc. In reversing the decision of the federal district court in Colorado in litigation surrounding Allergan’s Latisse® product, the federal appeals court held that no reasonable juror could have found that the generic drug manufacturer failed to prove that the patent claim lacks an adequate written description. The panel held that the patent description failed to narrow the disclosed universe of billions of compounds described in the specification to the smaller subset of compounds actually claimed (Duke University v. Sandoz Inc., No. 2024-1078 (Fed. Cir. Nov. 18, 2025)).

Duke University and Allergan Sales, LLC (“Allergan”) own U.S Patent No. 9,579,270 (the ’270 patent). The ’270 patent entitled, “Compositions and Methods for Treating Hair Loss Using Non-Naturally Occurring Prostaglandins,” relates generally to treating hair loss using compositions containing prostaglandin F (“PGF”). Allergan markets Latisse®, an FDA-approved topical solution for treatment of eyelash hair loss by stimulating hair growth. Drug manufacturer Sandoz Inc. manufactures and sells a generic version of Latisse. In 2018, Allergan sued Sandoz in the federal district court in Colorado, alleging that its generic drug product infringes claim 30 of the ’270 patent. Following a five-day trial, the jury found 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, both of which the district court denied. Sandoz appealed.

Written description. The Federal Circuit analyzed whether claim 30 of the ’270 patent includes a written adequate description. The written description requirement reflects the basic premise of the patent system: an inventor may obtain a patent only if the inventor discloses the invention to the public in sufficient enough detail that a person of ordinary skill in the art will understand that the inventor truly possessed the invention as claimed. In this case, the specification must provide sufficient indication as to how a skilled artisan would narrow the disclosed universe of billions of compounds described in the specification to the subset of just 1,620–4,230 compounds actually claimed.

Based on the evidence introduced at trial, no reasonable juror could find anything other than clear and convincing evidence that the ’270 patent fails to describe either (i) a representative number of species of claim 30’s subgenus or (ii) structural features common to all members of that subgenus. The specification fails to adequately direct the skilled artisan to the proper selection at the C1 position in order to arrive at the subgenus of compounds claimed by claim 30. Even accepting that the specification guides a skilled artisan towards the hairpin structure, leaving only variability at the C1 and Z ends to be navigated, the specification does not provide sufficient “blaze marks” to guide a skilled artisan to a PGF analog with an amide at the C1 position and a phenyl at the Z position, which are both required elements of the compounds comprising claim 30’s subgenus.

Any reasonable juror would have found, by clear and convincing evidence, that a person of ordinary skill in the art, reviewing the specification of the ’270 patent, would be unable to visualize or recognize the members of the subgenus claimed by claim 30 based upon the specification’s disclosures. The panel agreed with the generic drug manufacturer that claim 30 covers the use of a specific subgenus of PGF analogs to grow hair, but that the specification fails to show a skilled artisan that the inventors were in possession of that full subgenus, including the specific embodiment at issue in this litigation, bimatoprost. The specification fails to provide the relevant artisan with sufficient blaze marks or structural commonalities among the claimed compounds to lead an artisan to conclude that the inventor actually possessed the claimed invention.

In this case, the generic drug manufacturer overcame the doubly high burden of persuading the appeals court to overturn a jury verdict of no invalidity. Because no reasonable juror could have found that Sandoz failed to prove, by clear and convincing evidence, that claim 30 lacks adequate written description, the Federal Circuit reversed the district court’s judgment and held that the patent claim is invalid.

The Case is No. 24-1078.

Judge: Stark, L.

Attorneys: Jeffrey A. Lamken (MoloLamken LLP) for Duke University and Allergan Sales, LLC. William M. Jay (Goodwin Procter LLP) for Sandoz Inc.

Companies: Duke University; Allergan Sales, LLC; Sandoz Inc.

MainStory: TopStory Patent FedCirNews ColoradoNews