In a highly anticipated decision in Allergan v. MSN Labs., the Federal Circuit held yesterday that claims in a first-filed, first-issued, later-expiring patent cannot be invalidated for double patenting by claims in a later-filed, later-issued, earlier-expiring patent having a common priority date. Or, as stated more simply by the court, the first patent that issues on an invention “sets the maximum period of exclusivity of the claimed subject matter.”

In Allergan, the same three-judge panel that decided In re Cellect, explained that Cellect did not address the question at issue in Allergan, which was: “[U]nder what circumstances can a claim properly serve as an ODP reference?”

The answer: Claims of a second, later issuing patent cannot be applied against a first-filed, first-issued patent claim that shares a common priority date.

What does this mean? 

For now, it appears that patentees will not need to file terminal disclaimers in first-filed, first-issued patents to avoid invalidity for ODP based on any later-filed, later-issued patents in the same family, or face OTDP arguments in litigation of such patent families.

More to come? 

The court did not directly address whether a first-filed, later-issued patent would be immune against a later-filed, but first-issued patent or whether a later-filed, first-issued patent would be immune against an earlier-filed, later-issued patent. The court also did not directly address whether anything changes if the first and second patents were filed on the same day. However, the court strongly suggested that the first issuing patent “sets the maximum period of exclusivity.”