Living with Cellect – Three Best Practices

Article co-written by Yuri Levin-Schwartz, Ph.D., a law clerk at MBHB.

On Friday, January 19, 2024, the Court of Appeals for the Federal Circuit issued an Order refusing to rehear In re Cellect, LLC en banc. This likely means that the holding in In re Cellect will represent the law regarding patent term adjustment (PTA) as it applies to obviousness-type double patenting (ODP) for the foreseeable future. Thus, I present here three actionable practices that could be undertaken moving forward to attempt to avoid the unfortunate result rendered upon Cellect.

Brief Summary of the Case

As a very brief recap, the main issue in In re Cellect was whether accrued PTA for an issued patent should be applied before comparing expiration dates with another patent for possible ODP or after comparing expiration dates. The Federal Circuit decided that PTA should be applied before comparing expiration dates (which is particularly notable since this is the inverse of the decision the Federal Circuit rendered regarding patent term extension (PTE) in Novartis AG v. Ezra Ventures LLC, 909 F.3d 1367 (Fed. Cir. 2018)). Importantly, when PTA is applied before comparing expiration dates, it means that even patents that have the same effective filing date (and, therefore, would ordinarily have the same expiration date) can have different expiration dates (since accrued PTA can be, and usually is, different across different assets, even within the same patent family). This means that patents with the same effective filing date can be used for ODP rejections against one another and, in the case of Cellect, can be used to invalidate issued patents. In Cellect’s particular case, this meant that a later-filed, later-issued patent was used to invalidate an earlier-filed, earlier-issued patent based on ODP. Ordinarily, a terminal disclaimer (TD) can be used to obviate ODP between co-owned assets. However, in Cellect’s case, the patents had already expired at the time of litigation, so Cellect could not retroactively cure ODP for the patents in question using TDs. [1]

Practice Tips:

As a patentee or applicant, there are obviously multiple ways to attempt to inoculate yourself against potential ODP as a result of PTA, each with varying degrees of associated cost (both in attorney time and in patent term) and effectiveness. The three practices presented below attempt to strike a reasonable balance between these two factors.

Tip 1 – Review Your Patent Portfolio for Potential TD Filings at the Time of Issuance of Each New Patent

Filing TDs is a relatively easy way to obviate ODP issues between assets. That is, assuming a patentee is okay with the assets remaining co-owned and giving up the extra pendency in one of the assets. In its strongest form, this strategy would involve reviewing an entire patent portfolio for any asset that covers arguably related technical content and then filing a TD in that asset over the newly issued patent (and potentially filing a TD in the newly issued patent over the asset, as well). For large portfolios, though, this could be an incredibly onerous task for each newly issued patent. Hence, a more reasonable variant of this strategy would be to review only the immediate patent family (e.g., the parent application, grandparent application, sister application, etc. based on priority claims), and potentially any patent families flagged as related, for potential TDs (e.g., based on the expiration dates including any accrued PTA). This variation is likely to catch the majority of possible ODP issues already, since the immediate family is the most likely to include claims that are obvious variants of the newly issued claims.

Tip 2 – Consider Developing a Bespoke TD for Filing in Each Patent Application that Only Triggers Based on Certain PTA Conditions of Other Members of the Patent Family Being Met

Such a bespoke TD could state something to the effect of, “should a later-issued patent in this patent family have less PTA, and therefore an earlier expiration date, than a patent that issues from the present application, I hereby disclaim any term in the patent that issues from the present application that would extend beyond the expiration date of that later-issued patent.” Then, should a patent issue in the family (e.g., off of a continuation application) with an earlier expiration date, it would clearly not be usable for ODP purposes. While this practice would not inoculate the patent in question against all potential ODP issues (e.g., ODP issues arising from patents that issue from other families), it would represent a rather straightforward / boilerplate way to prospectively protect a portfolio.

Historically, most applicants/patentees chose to either file electronic TDs or to use one of the USPTO Forms (e.g., PTO/AIA/25, PTO/AIA/26, PTO/SB/25a, or PTO/SB/26a) when submitting a TD. Unfortunately, while these techniques are streamlined, they are also relatively limited in the ways you can provide information to the USPTO. For example, you cannot provide conditions under which a TD would trigger (instead, they are presumed to trigger immediately upon submission/acceptance of the TD). Thus, if a patentee wished to submit a conditional TD as described above, a bespoke TD would likely need to be adopted.

According to 37 C.F.R. § 1.321(a)(2), for a disclaimer to be recorded by the USPTO, it needs to “[i]dentify the patent and complete claim or claims, or term being disclaimed. A disclaimer which is not a disclaimer of a complete claim or claims, or term will be refused recordation.” Hence, it is perhaps arguable whether the USPTO would accept a bespoke TD. Still, as long as the conditions under which the TD would trigger and the assets that are being disclaimed are clearly laid out in the bespoke TD, it should be sufficient under the federal regulations. Further, given the result in In re Cellect, it would not be overly surprising if the USPTO develops a better system to analyze/ingest bespoke TDs in the coming months/years.

Tip 3 – Cite All Prior Patent Applications (Even Within the Same Family) in an Information Disclosure Statement (IDS) in Every Application to Ensure that the Examiner is at Least Ostensibly Considering PTA in Other Applications During Prosecution

One other aspect of In re Cellect that is worth discussing is that the Cellect patents were called back into the Patent Office as part of an ex parte reexamination proceeding. In order to initiate such a proceeding, a “substantial new question of patentability” must be present. 35 U.S.C. § 304. The USPTO, and subsequently the Federal Circuit, found that the ODP issue does constitute a “substantial new question of patentability.” Hence, one additional consideration going forward is how a patentee might avoid ODP being used as a “substantial new question of patentability.”

One way to attempt to avoid this is to have a patent examiner consider the applicant’s other patents/patent applications (e.g., within a patent family or across an entire portfolio) during patent examination. This is traditionally done by disclosing such patents/patent applications to the patent examiner using an IDS. Once an IDS has been filed, the patent examiner will consider the patents/patent applications and the associated patent numbers/patent application numbers will be printed on the face of any patent that ultimately issues (thereby indicating the patent examiner has considered them). This would make it more difficult for a third party to argue to the USPTO that a “substantial new question of patentability” is present based on ODP over one of those patents/patent applications (since the patent examiner has ostensibly considered them already and did not issue a rejection based on them). It is perhaps dubious to assume that a patent examiner would review/track the PTA associated with each patent/patent application and compare it to the PTA in the present application since doing so is somewhat intractable (as it would require the examiner to constantly review/reevaluate the ever-shifting accrued PTA throughout the life of not only the present application but also any co-pending applications). Still, by an examiner asserting that they have considered an IDS that cites the patents/patent applications in question, it is assumed that a patent examiner has properly done so. Hence, this practice technique is a reasonable way to reduce the likelihood that the USPTO later finds a “substantial new question of patentability” based on ODP that arises from differing amounts of PTA.


I hope the above has provided some guidance regarding protecting patent assets in this new post-In re Cellect regime. It turns out addressing “obviousness-type double patenting” is no longer so obvious. [2]


[1] For a more thorough discussion of the facts of the case, please see Kevin Noonan’s discussion on Patent Docs.   

[2] For some other potential considerations when addressing the consequences of In re Cellect, I recommend consulting Kevin Noonan’s write-up on Patent Docs.