In In re Cellect, the Court of Appeals for the Federal Circuit held that an award of patent term adjustment (PTA), extending the term of a patent by delaying its expiration to compensate a patentee for U.S. Patent and Trademark Office delays during examination, can render the patent invalid for obviousness-type double patenting (ODP), even over another patent issued in the same patent family and having the same priority date.
In Allergan, the Federal Circuit subsequently clarified that the holding in Cellect does not apply in all circumstances. Specifically, the Allergan court held that a first patent to issue in a family, even if it receives PTA (i.e., first-filed, first-issued patent), cannot be invalid for ODP over a later-issued patent in that family.
Earlier this month (on July 8, 2025), the U.S. District Court of Delaware issued a holding in Arkose Labs Holdings, Inc. et al. v. Datadome & Datadome Solutions, Inc., that would expand Allergan to hold that an earlier-filed, earlier-issued patent in a family, even if it received PTA, cannot be invalid for ODP over a later issuing patent in that family. This expands Allergan, because here the earlier-filed, earlier issued patent was not the first-filed, first-issued patent in the family, yet could still not be invalidated over a later-filed, later-issuing patent in that family.
Interestingly, of the patents held invalid in Cellect, one was invalidated under facts essentially identical to those at issue here. The Akrose court notes that an earlier-filed, earlier-issued patent in Cellect was invalidated over a later-filed, later-issued patent in the same family, but that the Allergan court later “clarified” Cellect, requiring the holding here.
The order is in the context of a motion to dismiss the plaintiff’s complaint, meaning it is very early in litigation. But if it ever proceeds to an appeal, it would present the Federal Circuit with an opportunity to directly confront the seeming-if-not-technical tension between its holdings in Cellect and Allergan.