Following the 2017 landmark Supreme Court decision in Actavis UK v Eli Lilly,(1) which introduced the doctrine of equivalents (ie, the principle that a patent may be infringed by dealing in a product or process considered equivalent to that protected by the granted patent) to UK patent law, the UK courts have handled a growing number of disputes where patentees have successfully relied on infringement by equivalence.
The doctrine of equivalents is now well-established in UK patent proceedings across many sectors, such as telecoms (for further details please see "Doctrine of equivalents – 'new normal' approach to patent infringement?").
The increasing prevalence of the doctrine of equivalents in UK patent proceedings has led to questions concerning whether any defences to infringement by equivalence are available and whether the doctrine applies to validity. While these issues have not yet been fully tested by the courts, judges are increasingly offering their views on them. Specifically, in two cases in 2019, the High Court commented on the so-called "Formstein defence", which derived from German case law and provides that if a patent is infringed under the doctrine of equivalents, the scope of the patent will be limited to a normal interpretation if the consequence of the interpretation under the doctrine is that the patent would be invalid. However, as the court did not have to directly confront the issue in either case, the availability of the Formstein defence in UK law was left uncertain.
A recent High Court judgment on a telecoms patent dispute handed down in May 2021, Facebook Ireland Ltd v Voxer IP LLC,(2) has shed some light on the availability of the Formstein defence to infringement by equivalents in the United Kingdom. Again, the court did not have to directly confront the issue, but obiter comments from Lord Justice Birss provided much welcomed clarity that if the alleged infringer's defence to infringement by equivalents had been at issue, the Formstein defence would have been the right approach.
The Facebook case related to a patent owned by Voxer that was concerned with messaging over telecoms devices.
The invention in Facebook enabled users to engage in, and transition seamlessly between, two modes of voice and video recordings. The two modes were live and time-shifted communication. The time-shifted mode delayed transmission, enabling the recipient to play or pause a message whenever they wished. Users could participate in multiple conversations at the same time and archive messages for later retrieval. The resulting conversation consisted of a series of recorded messages stored in a number of places such as the sender's device, servers ("hops") across the network and the receiver's device.
Facebook brought a revocation action against Voxer's patent on the basis of novelty and/or obviousness in light of two pieces of prior art. Facebook also alleged that the claims were insufficient and that Voxer's proposed amendments added matter.
Voxer counterclaimed, alleging that the patent was infringed by Facebook's live broadcast feature, which was available through the Facebook website and via the Facebook and Instagram iOS Apps. Infringement was alleged on normal construction of the claims and under the doctrine of equivalents.
An important practice point for patent lawyers arose from Birss LJ's findings at the Facebook pre-trial review in March 2021.(3) There, Birss LJ held that if a party intended to rely on infringement under the doctrine of equivalents, this must be expressly pleaded. As a minimum, the particulars of infringement should contain "a statement, by reference to each relevant claim feature (and claim), that equivalence is relied on". This approach was approved and expanded upon by Mr Justice Meade in the recent case Optis v Apple,(4) who suggested that the Actavis questions should be answered by reference to each claim feature to which the pleading of equivalents is directed.
Birss LJ held that Voxer's patent was invalid for obviousness over one of the pieces of prior art and that it was not infringed by Facebook's live broadcast feature.
In relation to infringement of the patent by Facebook's live broadcast feature, Birss LJ considered two questions. The first question was whether the live broadcast feature had the capability to provide users with both a live communication mode and a time-shifted communication mode of voice and video recordings. The second question related to the storage of recorded messages in Facebook's live broadcast feature.
The finding of non-infringement under normal construction was based on the technical features of Facebook's live broadcast and the inherent 10-second transmission delay. This delay was held to be "sufficiently large that the methods alleged to infringe do not support a live communication mode as required by claim 1".
The storage of messages in Facebook's live broadcast feature was also considered, both under normal construction and the doctrine of equivalents. Birss LJ held that there was no infringement under normal construction, based on the fact that the messages were stored in the content delivery network, thereby not infringing Voxer's patent, which taught storing recorded messages at each "hop" along the network. However, in considering infringement by equivalence, Birss LJ found all three Actavis questions in Voxer's favour, but also found that certain features were not satisfied or argued under equivalents, so there was no infringement by way of equivalents.
Facebook raised the Formstein defence in relation to its alleged infringement under the doctrine of equivalents. The Formstein defence originated from a 1986 German Federal Supreme Court judgment and extends the so-called "Gillette defence" to cover infringement under the doctrine of equivalents. The Gillette defence (named after Gillette Safety Razor v Anglo-American Trading)(5) is based on the fact that the patentee cannot validly claim something which was not new or that was obvious at the priority date of the patent. Therefore, if the defendant can show that the alleged infringement is obvious over the prior art that existed at the priority date, either the claims are invalid or they do not cover the alleged infringement as a matter of construction. In the Facebook judgment, Birss LJ summarised the consequence as "either way the alleged infringer must win and the patentee must lose".
The Formstein defence provides that a finding of infringement under the doctrine of equivalents cannot extend to cover something which was not new or that was obvious at the priority date. In other words, if a patent is not infringed under a normal interpretation but would be under the doctrine of equivalents, the scope of the patent will nevertheless be limited to a normal interpretation if the consequence of the broad interpretation under the doctrine of equivalents is that the patent would be invalid. Therefore, if the Formstein defence is successful, the scope of the patent must be confined to its normal construction.
Since the introduction of the revised test for infringement under the doctrine of equivalents in Actavis, the Formstein defence has been considered in principle by the UK courts. In Technetix BV v Teleste Ltd,(6) His Honour Judge Hacon suggested that the introduction of the Formstein defence into English law should be considered by the Supreme Court or Court of Appeal. In E Mishan & Sons, Inc v Hozelock Ltd,(7) Mr Justice Nugee held that the defence had no application in the case.
In the present case, as the patent was held to be invalid and not infringed, the Formstein defence was not in issue. However, Birss LJ went one step further than in Technetix and Hozelock by clarifying, in obiter comments, that the Formstein defence is the right approach when dealing with infringement under the doctrine of equivalents. He acknowledged that:
if [he] did have to decide the matter, [he] would hold that the right approach is the Formstein approach so that the conclusion if the equivalent device lacks novelty or is obvious is that the claim scope must be confined to its normal construction in that respect.
Birss LJ justified this finding on the basis that it would seem "harsh" to invalidate the patent on an equivalent basis when it was valid on normal construction. He reasoned that this approach provides certainty as "what else could the patentee do but write their claim in a way which, normally construed, did not cover the prior art". Birss LJ also acknowledged that this finding would align with the approach taken by other European Patent Convention countries that already apply the Formstein defence.
Infringement under the doctrine of equivalents is now well-established in UK patent proceedings but case law in this area is still developing. Although his comments in Facebook were obiter, Birss LJ appears have opened the door for the UK courts to directly consider the Formstein defence in respect of infringement by equivalence in the future.
The guidance on pleading the doctrine of equivalents provided by Birss LJ in Facebook, and subsequently by Meade J in Apple, will be welcomed by practitioners. Such guidance will be familiar and parallels can be drawn with Floyd J's (as he then was) comments in Ratiopharm GmbH v Napp Pharmaceuticals Holdings Ltd(8) regarding the particularisation of the common general knowledge (CGK) in respect of validity attacks based on obviousness over the CGK alone:
I consider that the time has come when the matter which is said to be common general knowledge ought to receive some more formal exposition in advance of the expert evidence stage.
Keeping their cards close to their chest for as long as possible is a clear tactic used by all parties in patent litigation. However, the consequences of the requirement to set out further detail at an earlier stage in UK proceedings goes beyond this, and requires both patentees and alleged infringers to consider their position in respect of both infringement and validity, and the precise scope of the patent and its core inventive concept prior to bringing or defending an infringement claim. This calls for more in-depth pre-action analysis and is likely to require the involvement of experts at an earlier stage.
The applicability of the doctrine of equivalents to validity merits further consideration. Meade J commented in Apple that this "is an extremely important point for UK patent law. It seems certain to need the consideration of the Court of Appeal and very probably the Supreme Court." Given the increasing prevalence of arguments relating to infringement by equivalents, the interplay between the doctrine and validity is likely to come before higher courts sooner rather than later.
For further information on this topic please contact Mark Marfé, Sarah Taylor, Alice Pringle or Beth Pendock at Pinsent Masons by telephone (+44 20 7418 8250) or email ([email protected], [email protected], [email protected] or [email protected]). The Pinsent Masons website can be accessed at www.pinsentmasons.com.