Obviousness-type double patenting (ODP) attempts to prevent the term of a “reference patent” claiming an obvious variant of a parent patent to exceed the term of the parent. This fulfills the mandate of the patent statute of “one patent per invention.”
When issuance dates were compared pre URAA (1994), the need to file for terminal disclaimer (TD) in the later-issued patent was simple to resolve. But then came patent term adjustment (PTA) – time tacked onto an expiration date for PTO delay—and URAA (1994)’s twenty years from filing or priority date term –arrived to complicate determination of if and when ODP is an issue.” A common priority date does not always guarantee a common expiration date.” (The quotes are all from Allegan).
The problem is that commonly owned patents that would otherwise expire on the same day due to a shared priority date may have different expiration dates due to award of PTA in one but not the other; or there may be a scattering of expiration dates due to differing PTA’s. “The patent subject to the TD cannot expire on any date later then the parent over which that TD was filed, even if it received [PTA]”. The TD specified expiration date rules.
In re Cellect, 81 F.4th 1216 (Fed. Cir. 2023), the Fed. Cir. established a “rule that, when it comes to evaluating ODP for a patent that has received PTA, the relevant expiration date is the expiration date including PTA. “(Owner had a number of interlocked patents with same priority date and a scattering of varying expiration dates due to different grants of PTA.)
In Allergan v MSN Labs. [and Sun], 111 F. 4th 1368 (Fed. Cir. 2024) the panel spent about 20 pages trying (and succeeding) to arrive at a just conclusion for what initially appeared to be a simple set of facts. In a para IV situation, Allegan sued MSN (“Sun “) for infringement of three patents related to an anti-pain drug. The three comprised the original ‘356 patent, claiming the drug per se, and two continuations—the ‘011 patent and the ‘709 patent. Apart from the key fact that the ‘356 patent had received 467 days of PTA, all three of the patents would have expired on the same date. So did the ‘356 patent improperly grab a much longer expiration date than the other two?
The district court said “yes” to Sun’s argument of improper extension of the term of the ‘356 patent, but Fed. Cir. reversed. The panel found that a finding of improper extension based solely on expiration dates was itself improper. The Court framed the question as “Can a first-filed, first issued, later-expiring claim be invalidated by a later-filed, later issued, earlier-expiring reference claim having a common priority date? We hold that it cannot.”
To rule otherwise would permit a first-issued patent to be treated like a later issued patent that can be invalidated by ODP. “The claims of the ‘356 patent do not “extend or prolong the monopoly [on the drug] beyond the period allowed by law, and therefore are not subject to ODP over the ‘011 and ‘709 patents… Put otherwise, the fact that the ‘356 patent expires later is of no consequence here because it is not a second later expiring patent for the same invention.” Because the ‘356 patent was the first patent in its family to be filed and to issue it does not extend any period of exclusivity on the claimed subject matter.”
The opinion further distinguishes precedent such as Gilead and Abbvie and uses the facts of Breckenridge to illustrate the injustice of a contrary holding. “A holding [that a first-filed, first-issued] parent patent having received PTA can be invalidated by a later-filed, later issued child parent with less if any PTA] would require patent owners …to file a TD disclaiming any term of the parent [patent] that extends beyond that of the child, which, given that the [parent and child] patents share a priority date, would amount to the disclaimer of only PTA. The parent patent, then would not receive the benefit of its congressionally guaranteed patent term. See 35 USC s.154(b) and would instead be limited to the presumably shorter term of its own child. Such a result would be untenable.”
