By: Caldwell

Everyone has advice to offer new lawyers about how to succeed. For those who started our career at a big law firm with hundreds of partners and an art collection, new associate “classes” congregate—or, at least, did in pre-COVID times—at the firm’s head office to learn how to start off on the right foot. The managing partner of the firm where I began my career said something during my new associate class congregation that I will never forget:


Why? Because “interesting” problems make for engaging law school hypotheticals and appellate topics. But “interesting” also means unclear. “Interesting” means expensive.

This advice has stuck with me throughout my career as an important reminder to put myself in my client’s shoes and to explain the potential risks, rewards, and unknowns of a given problem or opportunity in a way that cares for the sensitivities of the moment. Lawyers can and should have bedside manner and communicate with care, even facing uncertainty. But that doesn’t mean we can’t accept the challenge of the occasional “interesting” problem.

One such issue presented itself in a recent case. The question presented seems simple enough: when does a patent expire?

Most would say 20 years from its effective filing date, unless the USPTO calculated a patent term adjustment. Calculating this date often proves easy: the face of the patent typically shows its earliest effective filing date and the expiration date falls on the 20th anniversary of that filing date. But sometimes it takes a rare fact pattern to make us realize the answer to such a seemingly simple question may not be so simple.

To illustrate, what if a patentee asserted its patent on the 20th anniversary of its effective filing date? Better yet, what if a patentee asserted its patent on the sixth anniversary of the 20th anniversary of its effective filing date?[1] When specifically does the patent expire, and did the patentee file its complaint within the statutory period to seek damages?

At first, most everyone would likely agree that patent terms do not include both the full effective filing date and the full expiration date. We do not calculate time in this way in really any context. For example, a year runs from the beginning of January 1 through the stroke of midnight at the end of December 31, not January 1 through the next January 1. If we included the full day on both ends, a patent would have 20 years plus one day of life.

With that in mind, do we exclude the effective filing date or the 20-year anniversary date from the term?

When does a patent expire

Most litigators habitually count the way the Federal Rules of Civil Procedure tell us to count. We “exclude the day of the event that triggers the period” and “include the last day of the period, but if the last day is a Saturday, Sunday, or legal holiday, the period continues to run until the end of the next day that is not a Saturday, Sunday, or legal holiday.”[2] This seems straightforward, but a few aspects of this approach raise eyebrows. For instance, patent terms can expire on holidays or weekends without spilling over to the next weekday. And if a patent term does not begin until the day after the effective filing date, printed publications on the effective filing date could qualify as prior art.

Fortunately, the Federal Rules also tell us that they only “apply in computing any time period specified in these rules, in any local rule or court order, or in any statute that does not specify a method of computing time.”[3] The Federal Rules themselves do not set the term of a patent; U.S patent law does. Under 35 U.S.C. § 154, patents take effect “on the date on which the patent issues and ending 20 years from the date on which the application for the patent was filed in the United States” or whatever qualifies as the earliest effective filing date.[4]

Does 35 U.S.C. § 154 “specify a method for computing time,” so that the counting method in the Federal Rules of Civil Procedure does not apply and, in the alternative, patent terms begin at the beginning of the earliest filing date and end at midnight on the beginning of their 20th anniversary? To be sure, the strange practical effects of applying the Federal Rules method—automatic term extensions on weekends or holidays, prior art published on the filing date—appear to run counter to most practitioners’ working understanding of how patent terms work. But the law has countless idiosyncrasies that do not conform to a commonsense reading, so the inquiry does not end there.

In favor of discarding the Federal Rules’ method, 35 U.S.C. § 154(b) sets forth an entire process for deciding adjustments to—typically extensions of—a patent term. It directs the USPTO to issue regulations that create, for example, “procedures for the application for and determination of patent term adjustments under this subsection” and appeals of those decisions.[5] U.S. patent law thus sets the bounds of a patent term and delegated authority to the USPTO to decide when to deviate from those bounds. Does this leave room for the Federal Rules to play a role? If courts extend patent terms to award more damages if a patent would otherwise expire on a weekend or holiday, wouldn’t this also count as a term adjustment? If we think of patent term calculations by analogy to preemption issues in constitutional law, you might say U.S. patent law occupies the field of calculating and adjusting the term of a patent.

What do courts say? Not much, it seems. Only an exceedingly rare procedural posture would entice parties to litigate this issue: a patentee who sues on the sixth anniversary of the 20th anniversary of the effective filing date of a patent. We thus have little modern precedent to guide us.

History does tell us something, however. Before the 1995 Uruguay Round Agreements, patent terms ran “17 years from grant.”[6] Under this framework, pharmaceutical companies could sue for infringement on the same day their patent issued.[7] If the Federal Rules method applied, then, these suits could not have gone ahead until the day after the patent issued.

The parties have resolved the matter in which this issue arose, so we have more time to wait before a court supplies firm guidance on this question. But for those of us who savor the peculiarities of law that make us think about unsettled issues, these kinds of “interesting” problems keep us thinking well after our work for our clients has finished. When problems like this help us “break a mental sweat,”[8] we stay ready to solve whatever challenges our clients face. And we might even have fun along the way.

[1] U.S. patent law time bars certain claims: “no recovery shall be had for any infringement committed more than six years prior to the filing of the complaint or counterclaim for infringement in the action.” 35 U.S.C. § 286. A patentee that files on the sixth anniversary of the 20th anniversary of the patent’s filing date seeks damages for infringement occurring only on the 20th anniversary of the filing date itself. Anything earlier falls beyond the statute of limitations in § 286, while anything later occurred after the patent expired.

[2] Fed. R. Civ. P. 6(a)(1).

[3] Fed. R. Civ. P. 6(a).

[4] 35 U.S.C. § 354(a)(2).

[5] 35 U.S.C. § 354(b)(1)-(4).

[6] See, e.g., 35 U.S.C. § 154(c)(1).

[7] See, e.g., Helene Curtis Indus. v. Sales Affiliates, 105 F. Supp. 886, 891 (S.D.N.Y. 1952) (noting plaintiff sued “fifty-nine minutes after the patent issued at noon of December 4, 1915”).

[8] A classic line from the villainous Ben Stiller in 2004’s Dodgeball: A True Underdog Story.