Authored by: Jeremy J. Gustrowsky
In a major decision for pharmaceutical patents, the Federal Circuit reversed a $39 million jury verdict in favor of Duke University and Allergan Sales, LLC, finding that claim 30 of U.S. Patent No. 9,579,270—covering methods for treating hair loss with certain prostaglandin F analogs—was invalid for lack of adequate written description. The patent covered a narrow group of chemical compounds, but the court found that the patent’s written description was so broad and generic that it failed to sufficiently describe the specific compounds actually claimed.
The court explained that while the patent’s specification described billions of possible compounds, claim 30 only covered about 1,600 to 4,200 of them. Crucially, the patent did not provide even a single example of a compound within the claimed group, nor did it offer enough detail or “blaze marks” to guide a skilled scientist to the specific compounds covered by the claim. Instead, the patent simply listed many possible chemical options for each part of the molecule, leaving too many choices and not enough direction.
The Federal Circuit emphasized that for a patent claiming a group (or “genus”) of chemical compounds, the law requires either a representative number of examples or a clear description of the common features that would allow someone skilled in the field to recognize which compounds are covered. Because the patent here did neither, and even pointed away from the claimed compounds in its “preferred embodiments,” the court found that no reasonable jury could have concluded the patent met the legal requirements.
This decision highlights the importance of providing clear, specific disclosures in patent applications, especially for inventions involving large groups of chemical compounds. Simply describing a broad “forest” of possibilities is not enough—you have to show the path to the “trees” you want to claim.