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In , the Federal Circuit soundly disposed of arguments that the patent-in-suit was unenforceable due to laches based on an “unreasonable delay” in patent prosecution. Does the court’s reasoning foreclose the prosecution laches defense for any later-claimed invention disclosed in a published parent application? Is there merit to Judge Alsop’s concerns that unlimited continuation practice can inhibit competition and disrupt the careful balance struck between promoting and protecting innovation? 

The District Court Decision

            Judge Alsup’s Order on prosecution laches did not mince words: 

The essence of this order is that the patents issued after an unreasonable, inexcusable, and prejudicial delay of over thirteen years by the patent holder, Sonos, Inc. Sonos filed the provisional application from which the patents in suit claim priority in 2006, but it did not file the applications for these patents and present the asserted claims for examination until 2019. By the time these patents issued in 2019 and 2020, the industry had already marched on and put the claimed invention into practice.

To the extent the Order accepted that “Sonos diligently prosecuted [the parent] applications,” it still questioned why Sonos had not filed “parallel applications with new claims covering the invention” in the meantime. The Order found that Google was prejudiced by the delay, because “Google began investing in the accused products by at least 2015, when it released its first products that practiced the invention.” As stated in the Order, “There is no question that Google worked on, invested in, and used the claimed technology during the period of Sonos’s delay.” 

            The Order concluded:

It is wrong that our patent system was used in this way. With its constitutional underpinnings, this system is intended to promote and protect innovation. Here, by contrast, it was used to punish an innovator and to enrich a pretender by delay and sleight of hand. It has taken a full trial to learn this sad fact, but, at long last, a measure of justice is done. 

In sum, under, under the doctrine of prosecution laches, the patents in suit are UNENFORCEABLE. …. 

The Federal Court Opinion

The Federal Circuit opinion was authored by Judge Lourie and joined by Judge Prost and Judge Bumb, Chief Judge, United States District Court for the District of New Jersey, sitting by designation. 

The Federal Circuit explained that the doctrine of laches “may render a patent unenforceable when it has issued only after an unreasonable and unexplained delay in prosecution that constitutes an egregious misuse of the statutory patent system under the totality of the circumstances.” The defense of laches requires proof on two points: 

1. that the delay in prosecution was “unreasonable and inexcusable under the totality of circumstances” and 
2. that the defendant “suffered prejudice attributable to that delay.” 

  The opinion focused on the second point, and found it lacking: 

[N]o reasonable factfinder could conclude that the specification—which was published in 2013, before any of Google’s asserted investments—does not reasonably disclose over-lapping zone scenes. Google cannot be prejudiced by incorporating into its products a feature that was publicly disclosed in a patent application prior to its investment. 

In support of its ruling, the Federal Circuit cited cases the district court had attempted to distinguish: 

“[I]t is not improper for an applicant to broaden his claims during prosecution in order to encompass a competitor’s products, as long as the disclosure supports the broadened claims.” Liebel-Flarsheim Co. v. Medrad, Inc., 358 F.3d 898, 909 (Fed. Cir. 2004)

“[A]lthough subject matter disclosed but not claimed is generally dedicated to the public, there is an exception for subject matter “claimed in a continuation or other application.” Eli Lilly & Co. v. Hospira, Inc., 933 F.3d 1320, 1334 (Fed. Cir. 2019)

The Federal Circuit concluded that Google had “present[ed] no evidence that it suffered prejudice attributable to Sonos’s delay in claiming, but not disclosing, overlapping zone scenes,” and, therefore, that the district court’s finding of unenforceability was an abuse of discretion.

Is Prosecution Laches Still A Viable Defense 

Patent stakeholders who found the harsh language of Judge Alsop’s Order chilling may be relieved by the Federal Circuit decision. I found it interesting that the court did not delve into the course of prosecution, but instead rested its decision on lack of prejudice. Given the court’s ruling, could a defendant ever establish prosecution laches? Does the court’s rationale disrupt the balance of the patent system in favor of applicants who can afford to maintain continuation applications pending?