European Union: Patent Plausibility Uncertainty Persists, EPO Petition Shows

Patent applicants may face a plausibility challenge at the European Patent Office, or EPO, even though the concept of plausibility is nowhere to be found in the European Patent Convention. This concept generally concerns the idea that a purported effect of the claimed invention, e.g., a treatment of a particular disease, must have been credible to the skilled person at the time of filing of the application based on the disclosure in the application as filed.

The March 23, 2023, decision in the Enlarged Board of Appeal referral, known as G2/21, was expected to provide guidance on the application of the plausibility concept. However, a petition for review filed by the appellant/opponent on Jan. 17, 2024, in the appeal proceedings¹ that led to G2/21 referral shows that the uncertainty remains.

In the G2/21 referral, the Enlarged Board of Appeal was asked to provide guidance on the degree to which a technical effect relied upon for patentability must be rendered "plausible" from the application as filed. This issue can be of critical importance, especially in the life sciences field where patent applications are often filed before full clinical trials commence, meaning that the evidence available at the filing date to render the technical effects of the invention plausible is typically limited.

The case law of the Boards of Appeal was inconsistent on the standard to which plausibility was to be assessed, resulting in much uncertainty for applicants.

It was hoped that the Enlarged Board of Appeal would provide clear guidance on this point in G2/21. However, the Enlarged Board of Appeal rejected the notion of plausibility as a distinct concept, and set out a new framework for assessing whether a technical effect may be relied upon. By doing so, rather than clarifying the situation, the Enlarged Board of Appeal added to the uncertainty due to the need to interpret the new framework.

The recent petition for review shines a light on the uncertainty that still surrounds the issue of plausibility at the EPO, and the outcome could provide useful guidance on how the Enlarged Board of Appeal's orders in G2/21 should be interpreted.

What is plausibility?

Plausibility is not a formal requirement for patentability at the EPO. Instead, it is a concept that the Boards of Appeal have developed through case law for the assessment of both sufficiency of disclosure and the inventive step.

In relation to sufficiency of disclosure — where a technical effect or purpose is claimed, e.g., a therapeutic application — for an invention to be accepted as being sufficiently disclosed, the application, in combination with the common general knowledge, has to render it technically plausible that the invention does indeed provide the claimed technical effect or is suitable for the claimed purpose.²

In relation to the inventive step, plausibility is applied to consider whether it is plausible that an alleged technical effect relied on to establish inventive step is achieved by the invention.

In both cases, plausibility deals with the question of whether the application as filed, together with common general knowledge, renders it sufficiently plausible that a technical effect associated with the claimed invention is actually achieved.

Crucially, post-published data supporting a technical effect is typically only considered once the plausibility threshold has been met by the application as filed. In many cases, whether post-published data is considered can be a determining factor in their outcome, particularly in the life sciences field.

The referral to the Enlarged Board of Appeal that led to decision G2/21 resulted from different Boards of Appeal applying different standards to assess plausibility. Some Boards of Appeal applied a standard termed "ab initio plausibility." The referring board in G2/21 characterized this standard as requiring an effect to be rendered plausible from the application as filed or the common general knowledge before post-published evidence can be considered.

By contrast, other Boards of Appeal applied an "ab initio implausibility" standard in which post-published evidence should be taken into consideration unless the skilled person would have had reason to consider the effect implausible.

The referring board in G2/21 therefore asked the Enlarged Board of Appeal to provide guidance on whether any plausibility threshold should be applied before post-published data is considered, and, if so, whether the "ab initio plausibility" or "ab initio implausibility" standard should be applied.

However, instead of indicating what standard of plausibility should be applied, the Enlarged Board of Appeal rejected the notion of plausibility as a distinct concept. In place of indicating what standard of plausibility should be applied, the Enlarged Board of Appeal handed down the following two orders:

• "Evidence submitted by a patent applicant or proprietor to prove a technical effect relied upon for acknowledgment of inventive step of the claimed subject matter may not be disregarded solely on the ground that such evidence, on which the effect rests, had not been public before the filing date of the patent-in-suit and was filed after that date."
• "A patent applicant or proprietor may rely upon a technical effect for inventive step if the skilled person, having the common general knowledge in mind, and based on the application as originally filed, would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention."

Although the Enlarged Board of Appeal rejected the notion of plausibility, its decision seems to nonetheless retain the concept in some form.

In particular, Order 2 specifies that the proprietor may rely on a technical effect and supply post-published data in support of said effect if the skilled person "would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention."

The Enlarged Board of Appeal therefore retained some requirement for the technical effect to be derivable from the application as filed, but failed to provide the clarity that had been hoped for based on the referred questions.

The decision in G2/21 was therefore seen by many to leave open more questions than it answered. In particular, it remained unclear how the Enlarged Board of Appeal's Order 2 was to be applied in practice.

What is a petition for review?

A petition for review provides a way to challenge the otherwise final decision of a Board of Appeal and, if successful, the decision under review is set aside, the appeal procedure is reopened, and the fee for petition for review is reimbursed.

However, petitions for review are generally filed only under exceptional circumstances, and past petitions show that the process is challenging. Fewer than 5% of petitions for review filed since 2009 have been found to be admissible and allowable, amounting to a total of only 10 successful petitions for review in the last 15 years.³

What is the petition for review in question?

The petitioner argues that a fundamental violation of its right to be heard occurred in relation to the interpretation of Order 2 of G2/21 by the Board of Appeal in T 116/18 dated July 28, 2023. It asserts that the Board of Appeal reformulated Order 2 into a new test, which the petitioner did not have the opportunity to comment on during the appeal proceedings, thus violating the petitioner's right to be heard.

Specifically, the Board of Appeal noted that Order 2 requires that the skilled person would derive the effect as being (1) encompassed by the technical teaching, and (2) embodied by the same originally disclosed invention, reformulating the second requirement as:

The petitioner alleges that this is a new test that is different from Order 2 of G2/21 and makes several points in support of this position.

First, the petitioner argues that the new test implies that the "would" in Order 2 need not be taken into consideration. The petitioner seems to be arguing that where Order 2 refers to whether the skilled person "would derive said effect," the new test uses the less strict approach of "would the skilled person ... have legitimate reason to doubt."

Second, the petitioner argues that the board has defined the term "technical teaching" as corresponding to "the purported technical effect together with the claimed subject-matter."

Third, the petitioner argues that the board has defined "the originally disclosed invention" as corresponding to "the broadest technical teaching of the application as filed."

Finally, the petitioner argues that the reformulation stipulates that any purported technical effect may give rise to a patent, provided that it can be considered to be an embodiment of "the broadest technical teaching of the application as filed."

The implication is that the petitioner considers that the board construed the term "the same originally disclosed invention" recited in Order 2 too broadly to encompass "the broadest technical teaching of the application as filed", and that this is inconsistent with Order 2 of G2/21.

The petitioner asserts that the alleged nonobservance of the right to be heard on this issue led to the adverse decision because application of the new test by the board when considering Order 2 of G2/21 resulted in the technical effect in question being relied upon for inventive step, which ultimately led to the maintenance of the opposed patent.

In further support of the petition for review, the petitioner alleges that it did not make certain arguments it is alleged to have made according to the written decision of the Board of Appeal. The petitioner argues that these misrepresentations amount to a fundamental violation of the right to be heard because it was not given an opportunity to present comments on these misunderstandings, which also relate to the conditions of Order 2.

What is the significance of the petition for review?

As previously mentioned, the success rate for petitions for review at the EPO is very low. Thus, the petitioner may not be successful in this instance. However, even if the Enlarged Board of Appeal does not agree with the petitioner, this petition may still provide useful guidance on how the orders of G2/21 should be interpreted.

The petitioner is objecting that the Board of Appeal's misapplication of Order 2 of G2/21 resulted in a lower standard being set for whether the skilled person would derive a technical effect as being "embodied by the same originally disclosed invention," and that it did not have an opportunity to comment on this new test.

Relating the petition to the questions originally referred to the Enlarged Board of Appeal in G2/21, it might be argued that the Board of Appeal in T 116/18 has effectively interpreted Order 2 of G2/21 as endorsing the "ab initio implausibility" standard by using the phrase "would the skilled person ... have legitimate reason to doubt" in its question. In other words, the plausibility threshold is met unless the skilled person would have had reason to consider the effect implausible.

Thus, if the Enlarged Board of Appeal agrees with the petitioner that the Board of Appeal has applied a new test, it will perhaps signal that the Enlarged Board of Appeal did not intend for Order 2 to be interpreted in this way. Indeed, it could be argued that the wording of Order 2 is more in line with the "ab initio plausibility" standard as it requires a consideration of whether the skilled person "would derive said effect."

It will therefore be interesting to see whether the outcome of the petition for review provides guidance on this point as it relates closely to the original questions referred to the Enlarged Board of Appeal in G2/21, which many stakeholders would appreciate clarification on.

The outcome of the petition may also shed some light on how broadly "embodied by the same originally disclosed invention" in Order 2 is to be interpreted. The Board of Appeal has interpreted that phrase to encompass "the broadest technical teaching of the application as filed," and the outcome of the petition may indicate whether the Enlarged Board of Appeal considers this to be in line with Order 2.

Even if the Enlarged Board of Appeal does not admit the petition for review, or avoids engaging with these points, the mere existence of the petition is revealing in and of itself. Many stakeholders were disappointed by the rather vague orders handed down by the Enlarged Board of Appeal in G2/21, which seemed to do little to answer the questions that had been referred.

Indeed, the fact that the first attempt at application of the Enlarged Board of Appeal's orders by the referring board has resulted in a petition for review highlights the uncertainty that still surrounds this important issue, and that the original questions referred to the Board of Appeal still remain very open and relevant, despite the Enlarged Board of Appeal's attempt to move away from the concept of plausibility.

Footnotes

1. EPO decision T 116/18.

2. EPO decisions T 1599/06 and T 609/02.

3. Based on published petition for review decisions at the

Originally published by Law360

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