Applying G 2/21: Preliminary opinion from the referring Board of Appeal on post-filed evidence appeal (T 0116/18)

Earlier this year, the Enlarged Board of Appeal (EBA) published its decision G 2/21 on the issue of post-published evidence. The question in G 2/21 was whether post-published evidence can be used to support a purported technical effect relied on for inventive step. In G 2/21, the EBA reiterated existing case law that, for a technical effect relied on for inventive step, what matters is what the skilled person would understand (in view of common general knowledge) from the application as filed. The general principle, said the EBA, was that the technical effect should be both encompassed and embodied by the technical teaching of the application as filed (IPKat). The EBA itself acknowledged that this was a somewhat vague conclusion and left it to the Boards of Appeal to interpret the decision. 

We now have the preliminary thoughts from the referring Board of Appeal on how G 2/21 should be applied. The Board of Appeal suggests two different possible interpretations of the EBA's reasoning for discussion between the parties at oral proceedings: 1) the technical effect of the invention must not be in doubt in view of the application as filed and/or 2) the application as filed must mention the technical effect. 

Oral proceedings are scheduled for 28th July 2023. The hearing will be held in-person following a request by the Opponent for a change from ViCo proceedings.

The issue at hand: Evidence and problem solution

The problem solution approach to inventive step adopted by the EPO relies on identification of the so-called "closest prior art" with respect to the claimed invention. The EPO's reliance on the concept of "the closest prior art" can create two problems for applicants. First, according to the problem solution approach, the claimed invention should solve the problem to be solved in view of the closest prior art. However, the exact document representing the "closest prior art" may not be known to an applicant at the filing date. The closest prior art may not even become known until it is cited by an opponent post-grant. If the patentee was unaware of obscure prior art at the filing date, they will not have had the opportunity to ensure the application contained sufficient data demonstrating the superiority of the invention over this prior art (e.g. direct comparison data). The question thus becomes whether the patentee should be allowed to file additional data after the filing date once the legal concept of "the closest prior art" has been found and decided upon by the patent office.

Another challenge faced by applicants for patents at the EPO, occurs when a purported technical effect relied on for inventive step is impugned by negative data filed after the filing date by a third party. A patentee may purport that an invention has a broad technical effect, justifying a broad claim scope. To challenge such a claim, an opponent may provide data of an embodiment within the claim scope for which the technical effect does not hold. Is the patentee then permitted to rely on a different narrower or alternative technical effect, and submit new data in support of this effect? What if there were no substantiated doubts against the broader technical effect at the filing date? These are some of the key questions that still need answering in the referring case for G 2/21

The referring case in G 2/21 (T 0116/18)

Back to moths
The patent at issue in the referring case of G 2/21 claimed a combination of known insecticides (EP 2484209). The application as filed provided data demonstrating the synergistic effect of the insecticide combo against two species of moth, in support of a technical effect of synergy of the insecticide combo against moths in general. However, at opposition, the Opponent filed new data showing that the insecticide combo did not in fact have the purported effect against one of the exemplified moth species at certain weight ratios. The Opponent argued that the purported technical effect could thus not be supported. In response, the Patentee filed their own new data showing the technical effect of the insecticide combo against a third species of moth. The Patentee argued that the technical effect of the invention was the narrower effect of the insecticide combo against this third species.

The Patentee in T 0116/18 thus wished to rely on a post-hoc inventive step argument based on new data in response to new negative data presented by a third party after the filing date (IPKat). The Board of Appeal reached the interlocutory decision that inventive step could only be acknowledged if the Patentee's post-filed data could be taken into account.

Preliminary opinion of the Board of Appeal in T 0116/18

The EBA in G 2/21 did not provide much in the way of guidance to the referring Board on how to implement the decision. The Board of Appeal in the referring case (3.3.02) was therefore left with the unenviable task of applying the abstract principles provided by G 2/21. The Board of Appeal's preliminary opinion gives us a first indication of how the Board of Appeal will approach this task.

In G 2/21, EBA the decided that:

"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" (Headnote II)

In its preliminary opinion, the Board of Appeal outlines two possible interpretations of this reasoning.

First interpretation of G 2/21: ab initio lack of substantiated doubt

According to the first interpretation, the EBA in G 2/21 endorsed the position that a technical effect relied on for inventive step must not be implausible in view of the application as filed, in view of CGK (lack of "ab initio implausibility"). In other words, if there substantiated doubt, supported by verifiable facts, that the invention had the purported technical effect in view of the application as filed and CGK, the technical effect can not be relied on. [Are you still confused about "plausibility"? If so, see IPKat: Plausibility demystified]

Even if we follow this first interpretation, however, we are still left with the question of what to do with contradictory data about a purported technical effect which only becomes available after the filing date (e.g. is obtained by an Opponent). In particular, what consequence does such data have on the question of whether the technical effect was plausible or not in the application as filed (IPKat)? In other words, was the effect plausible at the filing date if the doubts over the technical effect of the invention were only substantiated with verifiable facts after the filing date?

Interestingly, following the G 2/21 decision, the Opponent has now submitted additional new evidence purporting to show that the claimed insecticide combo is also "mostly not synergistic" against the third species of moth which is subject of the Patentee's revised inventive step argument.

Second interpretation of G 2/21: The effect must be derivable in the application as filed

The second interpretation of G 2/21 put forward by the Board of Appeal in T 0116/18 is that the important question is merely whether a purported technical effect relied on for inventive step is derivable or mentioned in the application as filed. In the case in question, the effect of the insecticide combo on the third moth species in particular (as opposed to all moths, or the first and second moth species) was not mentioned in the application as filed. Was the purported technical effect therefore derivable from the application as filed? This question is of course separate to whether or not the technical effect would have been plausible had it been derivable. If this interpretation is followed, we will then have the further question of whether an explicit or implicit disclosure is required for a "derivable" technical effect. For example, is a disclosure of synergy against all moth species, an implicit disclosure of synergy against a specific moth species? To this Kat, the EBA's use of the phrase "derivable" implies that an explicit mention of the technical effect is not required (see G 2/21 r.65). 

Final thoughts

The Board of Appeal T 0116/18 is currently unsure whether to be "a derivable" technical effect "encompassed and embodied by the technical teach of the application as filed": 1) the technical effect must not be in doubt from the perspective of the skilled person in view of the application as filed and CGK, and/or 2) the technical effect must be (implicitly or explicitly) mentioned in the application as filed. Importantly, we also still lack clarity over one of the key questions at issue in the referring case: the impact of contradictory post-filed data on the question of whether there are "substantiated doubts" about an invention or its technical effect at the filing date in view of CGK. The oral proceedings and the Board of Appeal decision will hopefully provide further guidance on these questions. 
Applying G 2/21: Preliminary opinion from the referring Board of Appeal on post-filed evidence appeal (T 0116/18) Applying G 2/21: Preliminary opinion from the referring Board of Appeal on post-filed evidence appeal (T 0116/18) Reviewed by Rose Hughes on Monday, June 19, 2023 Rating: 5


  1. First, the requirement of nonobviousness of art 56 can be reassessed anytime (e.g., in opposition), but must always be judged as of the date of fíling of the patent application. And second, absolute proof of the technical effect relied upon through experimental data is not required. If we don’t get back to these two well-established principles of the EPO case law, and don’t stick to them strictly, we run into insurmountable trouble. The referring board insists and would have wished a catalogue of detailed instructions, but the EBA has already made clear in G2/21 that from the case law only general principles of general application are to be derived, not a casuistry.

  2. So now we have the board in T 116/18 saying that G2/21 might mean that *both* ab initio plausibility *and* ab initio implausibility might apply - or possibly neither - or possibly another interpretation yet to be determined; and Arnold LJ in the U.K. “apixaban” (Sandoz & Teva v BMS) case saying that he considers G 2/21 to be closer in substance to ab initio plausibility, and doubting that the ab initio plausibility/implausibility approaches can be reconciled in that they could still lead to divergent outcomes on the same facts, despite the EBA’s attempt to sidestep this issue.

    Nice job, Enlarged Board!


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