Federal Circuit Clarifies Proper Double-Patenting Reference

In Allergan USA v. MSN Labs, the US Court of Appeals for the Federal Circuit held that later-filed, later-issued claims cannot serve as proper reference for invalidating earlier-filed, earlier-issued claims having the same priority date under obviousness-type double patenting (ODP), clarifying its decision in In re Cellect by explaining which reference claims can be considered proper for ODP analysis.

ODP is a judicially created doctrine with a policy objective of preventing an unjustified timewise extension of exclusivity beyond the life of a patent. In certain situations, claims in a continuation application are rejected over claims in a parent application if they are considered obvious (and thus, patentably indistinct) in light of the claims in the parent.

In In re Cellect LLC, 81 F. 4th 1216 (Fed. Cir. 2023), the Federal Circuit rejected the argument that ODP cannot cut off patent term adjustment (PTA) and that the determination of whether claims are unpatentable under ODP should be based on the expiration date that does not include the addition of any duly granted PTA. The court instead held that “when it comes to evaluating ODP on a patent that has received PTA, the relevant expiration date is the expiration date including PTA—not the original expiration date measured twenty years from the priority date.” Allergan USA v. MSN Labs, 24-1061 (Fed. Cir. August 13, 2024), slip op at 14. Notably, all patents at issue in Cellect had expired.

The decision was of interest because the analysis did not consider when the patents were granted, and thus, did not consider whether the patentee indeed intended to unjustifiably extend the patent term. The ruling put patents that were filed earlier and had a later expiration date due to PTA at risk of invalidation under ODP over later-filed, earlier expiring patents (because the later-filed patents had no or shorter PTA).

In Allergan, the court (which happens to be the same three-judge bench that issued the Cellect ruling) provided some clarity by ruling that claims of a later-filed, later-issued patent and having the same priority date as an earlier-filed patent cannot properly be used as a reference for invalidating claims of the earlier-filed, earlier-issued patent that expires later than the later-issued patent (by virtue of having a longer PTA). Specifically, the court clarified that while Cellect answered the question of whether, for the purposes of ODP analysis, the expiration date of patent should or should not include PTA, it did not address the question of “under what circumstances can a claim properly serve as an ODP reference.” Id. at 15.

The court reasoned that the purpose of the ODP doctrine is to prevent patentees from obtaining a second patent on a patentably indistinct invention to effectively extend the life of a first patent to that subject matter. Consequently, claims of an earlier-issued patent cannot be considered to extend or prolong the patent exclusivity beyond the period allowed by law because it is not a second, later expiring patent for the same invention.

The ruling comes as relief to many patentees who were concerned about the risk to earlier issued parent patent(s) that had a substantial amount of patent term adjustment from later-issued or later-filed and still-pending continuation applications. While the decision does not mitigate the possible risk to patents from the proposed rulemaking of the US Patent and Trademark Office that would render invalid a patent on one end of a terminal disclaimer where a patent on the other end of the terminal disclaimer was invalidated, the rule provided in this decision clarifies that a later-filed, later-issued claim sharing a same priority date is not a proper reference for ODP.

In summary, earlier-filed, earlier issued patents with long PTAs seem to be safe from later-filed, later-issued claims with same priority date being used as ODP references—for now.