Federal Circuit Clarifies Scope of Obviousness-Type Double Patenting After Curveball Thrown by In re Cellect

In its 2023 decision in In re Cellect, the U.S. Court of Appeals for the Federal Circuit appeared to expand the risk that patent portfolio holders would lose obviousness-type double patenting (ODP) challenges because of different, colliding expiration dates between a parent and child patent as a result of Patent Term Adjustment (PTA). 

In Cellect, a series of patents sharing a common priority date were invalidated under obviousness-type double patenting over the claims of other members of that same portfolio. The ODP challenge was raised during ex parte reexamination, but not raised by the examiner during prosecution. By the time the case reached the Federal Circuit, there was no opportunity to remedy the situation by filing a terminal disclaimer, and multiple patents were left invalidated. The case caused great consternation for patent holders, as they faced the possibility that similar time bombs could be lurking in existing patent portfolios, as well as the prospect of having to self-police the filing of voluntary terminal disclaimers.

The Federal Circuit recently clarified the scope of its ruling in Cellect, holding in Allergan USA v. MSN Labsthat “a first-filed, first-issued, later-expiring claim cannot be invalidated by a later-filed, later-issued, earlier-expiring reference claim having a common priority date.” 

This decision provides increased protection for first-filed patents that receive significant PTA by shielding them from ODP challenges based on their own continuations that share the same priority date.

The fundamental purpose of the ODP doctrine is to prevent improper and unjustified attempts to extend patent exclusivity beyond the initial term by obtaining subsequent patents with sequentially later expiration dates. In Cellect, a later-expired claim was challenged as ODP based upon an earlier-expired but later-filed and issued patent. The court held in that case that “ODP for a patent that has received PTA, regardless [of] whether or not a terminal disclaimer is required or has been filed, must be based on the expiration date of the patent after PTA has been added.”

A similar fact pattern was at issue in Allergan. The district court invalidated the subject patent because it read Cellect as binding it to consider expiration dates alone in the ODP analysis, stating that “[w]hen analyzing ODP, a court compares patent expiration dates, rather than filing or issuance dates.

Cellect Addressed a Different Question 

On appeal, the Federal Circuit disagreed with the district court’s analysis, finding “that Cellect did “not address, let alone resolve, any variation of the question presented here—namely, under what circumstances can a claim properly serve as an ODP reference.” Instead, the court noted that its holding in In re Cellect “is only controlling in this case to the extent that it requires us to consider, in our ODP analysis,” the challenged patent’s expiration date after the addition of PTA, not the expiration date that it would have shared with the reference patents in the absence of a PTA award.” 

The Federal Circuit clarified that “the fact that the [parent] patent expires later is of no consequence here because it is not a ‘second, later expiring patent for the same invention” and that “[a]s the first-filed, first-issued patent in its family, [the parent patent] is the patent that sets the maximum period of exclusivity for the claimed subject matter and any patentably indistinct variants.”

The court accordingly concluded that a holding that “a first-filed, first-issued parent patent having duly received PTA can be invalidated by a later-filed, later-issued child patent with less, if any, PTA—would not only run afoul of the fundamental purposes of ODP, but effectively abrogate the benefit Congress intended to bestow on patentees when codifying PTA.” 

Specifically, the court continued, “Such a holding would require patent owners, in order to preserve the validity of the parent patent, to file a terminal disclaimer disclaiming any term of the parent that extends beyond that of the child, which, given that the patents share a priority date, would amount to the disclaimer of only PTA. That parent patent, then, would not receive the benefit of its congressionally guaranteed patent term… and would instead be limited to the presumably shorter term of its own child. Such a result would be untenable.”

Open Questions Remain

There are a number of questions Allergan does not address. Specifically, later-filed continuations remain at risk over other pending continuations in the same patent family (the situation in Cellect).

In reality, much gnarlier fact patterns exist than the one in Cellect. For example, in this day and age of accelerated examination – combined with the inherent variability with which the USPTO examines different applications – it is not uncommon to end up with a first-filed, later-issued claim being rejected due to a later-filed, earlier-issued reference claim. Given, as the Allergan court states, that its ruling is “the only conclusion consistent with the purpose of the ODP doctrine, which is to prevent patentees from obtaining a second patent on a patentably indistinct invention to effectively extend the life of the first patent to that subject matter,” the same conclusion, it seems, should apply but is not explicitly addressed here. 

One can take it even a step further, given that a single overlapping inventor or applicant can be grounds for raising an ODP rejection. It is also possible that an earlier-filed, later-issued claim can be rejected by a later-filed, earlier-issued reference claim that does not share a common priority date and is filed by different inventive entities and applicants. Given that inventors will move around and study at or work for various entities – and, oddly enough, may continue to innovate in areas of existing expertise – this is not a zero-probability occurrence. It is also not a situation current ODP jurisprudence is equipped to handle (the remedy of a terminal disclaimer does not apply in such a fact pattern due to diversity of ownership) nor, given the stated purpose of the ODP doctrine above, one in which it was ever likely intended to apply. 

If you have questions about the Allergan decision or would like to discuss its impact on your patent portfolio, please contact Brent Nix at JMIN.