Federal Circuit Invalidates $39 Million Hair Loss Drug Patent in Sandoz Victory
核心洞察
The Federal Circuit reversed a $39 million jury verdict against Sandoz, finding Duke University (搜索) and Allergan's patent for eyelash hair loss (搜索) treatment invalid for lack of adequate written description.
The court determined that the patent's specification was too broad, encompassing billions of compounds while claiming only 1,620, failing to provide sufficient guidance to skilled artisans.
Sandoz successfully challenged the validity of claim 30 of U.S. Patent No. 9,579,270, which covers prostaglandin (搜索) formulations for treating hair loss (搜索) including Allergan's FDA-approved Latisse.
The US Court of Appeals for the Federal Circuit has reversed a $39 million patent infringement verdict against Sandoz Inc., ruling that Duke University (搜索) and Allergan Sales LLC's patent for topical eyelash hair loss (搜索) treatment is invalid for lack of adequate written description. The precedential decision, authored by Judge Leonard P. Stark and issued on November 18, 2025, represents a significant victory for the generic drug manufacturer in its challenge to U.S. Patent No. 9,579,270.
Patent Dispute Over Hair Loss Treatment
The disputed patent describes a method for growing hair by topically applying prostaglandin (搜索) chemical compounds. Allergan markets Latisse, an FDA-approved topical solution for treating eyelash hair loss (搜索), while Sandoz manufactures and sells a generic version of the product. In 2018, Allergan sued Sandoz alleging that its generic drug product infringed claim 30 of the patent.
During the litigation, Sandoz stipulated to infringement but challenged the validity of the patent 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, awarding Allergan $39 million in infringement damages.
Written Description Deficiency
The Federal Circuit's reversal centered on the fundamental mismatch between the patent's broad specification and its narrow claims. Sandoz argued that the patent specification encompasses a "universe of billions of compounds," while claim 30 is limited to roughly 1,620 of those potential compounds. The court agreed that this vast discrepancy demonstrated that the patent inventors did not actually possess the invention claimed in claim 30.
According to the court's analysis, the patent specification failed to provide sufficient "blaze marks" to direct a skilled artisan to the claimed subgenus of compounds. The court explained that a specification must "provide adequate direction which reasonably would lead persons skilled in the art to compounds actually claimed in claim 30."
Court's Reasoning and Precedent
The Federal Circuit concluded that no reasonable juror could find anything other than clear and convincing evidence that the patent fails to describe either a representative number of species of claim 30's subgenus or structural features common to all members of that subgenus. The court characterized the patent disclosure as "at best a menu of available atoms, moieties, and functional groups" from which a skilled artisan could populate certain structures.
Using vivid analogies, the court compared the patent disclosure to a maze, stating 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." The court further noted that "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.'"
Legal Standards and Review
The Federal Circuit applied Tenth Circuit law in reviewing the district court's denial of Sandoz's motion for judgment as a matter of law (JMOL). Under this standard, the court could reverse only if the evidence was such that, without weighing witness credibility, the only reasonable conclusion favored Sandoz. The court determined that the written description requirement presents a question of fact regarding whether the patent specification discloses sufficient information for a person of ordinary skill in the art to conclude the inventor possessed the full scope of the invention.
Impact on Patent Validity Standards
The decision reinforces strict requirements for written description in chemical compound patents, particularly those with broad specifications claiming narrow subsets of compounds. The court's ruling that 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" establishes important precedent for evaluating whether patent specifications provide adequate guidance to skilled artisans.
This reversal eliminates the $39 million damages award and validates Sandoz's generic version of the eyelash hair loss (搜索) treatment, potentially affecting the competitive landscape for prostaglandin (搜索)-based hair growth products.