Reliance on a silent technical effect: Application of G 2/21 to semiconductors (T 2465/19)

The Enlarged Board of Appeal (EBA) decision in G 2/21 arose from a case seeking guidance on the evidence requirement for a purported technical effect relied on for inventive step (IPKat). However, in its final order, G 2/21 focussed less on the amount of evidence needed to support an invention, and more on the disclosure requirement for a technical effect relied on for inventive step. Therefore, while the interpretation of G 2/21 has so far predominantly been in Board of Appeal cases in the biotech field (T 0873/21, T 1394/21, T 0116/18), G 2/21 also has relevance to any case for which a new technical effect, not mentioned in the application as filed, is relied on for inventive step. The Board of Appeal in T 2465/19, for example, cited G 2/21 in a case related to the inventive step of a semiconductor. 

G 2/21 case catch-up: Experimental evidence, the problem solution approach and disclosure of the technical effect

Searching for semiconductors

The referral in G 2/21 related to the evidence requirements for inventive step. The problem solution approach to inventive step employed by the EPO relies on identification of the "closest prior art" with respect to the claimed invention. This often creates a problem for applicants in cases where a purported technical effect requires experimental evidence. In such cases, the embodiment representing the "closest prior art" may be obscure and not known to the inventors at the filing date.  As a consequence, the applicant may fail to include data demonstrating the technical effect of the invention in view of the closest prior art in the application as filed. In such cases, the problem faced by the patentee is a need for experimental evidence that only becomes apparent after the filing date of the application. The problem of post hoc identified prior art was one of the central problem giving rise to the referral in G 2/21:

"it is often necessary, like in this case, to provide post-published evidence (i.e. evidence that was not public before the filing date of the patent in suit and was filed after that date) as proof that the problem has been solved (i.e. that the alleged technical effect is actually achieved). This applies in particular when the objective technical problem has to be reformulated, e.g. with regard to a closest prior-art document previously unknown to the patent proprietor" (T 0116/18, r. 13.2)

Application of G 2/21 outside of biotech

There is currently some debate over the potential relevance of G 2/21 outside the setting of biotech and pharmaceutical inventions. This Kat has previously observed that G 2/21 is likely to be relevant in any field that requires evidence of a technical effect over the closest prior art (IPKat), including software and machine learning invention (T 2465/19).

However, the problem of post-hoc identified prior art may even be relevant to fields for which experimental evidence is not generally required. Even for mechanical inventions, there may be circumstances where the applicant needs to rely on a technical effect for inventive step that was not mentioned in the application as filed. The application as filed may, for example, disclose all the features of the invention, but not describe the advantages of these features. The decision in T 2465/19 demonstrates that G 2/21 is also relevant to these cases.   

T 2465/19: G 2/21 and semiconductors

The case in T 2465/19 related to a patent application (EP2353183, Wolfspeed) for a semiconductor. The issue on appeal was inventive step. The Examining Division (ED) objected that the application as filed was silent about the technical effect of the feature distinguishing the claimed semiconductor from the prior art. For the ED, the distinguishing feature was also merely an arbitrary selection providing no advantage over the closest prior art. In response, the applicant argued that the disclosure of advantages in the description is not a requirement for inventive step, and that the claim should be construed as providing a feature that did provide an advantage. 

On appeal, the Board of Appeal, citing G 2/21, agreed with the applicant that “the technical effect of an invention over the closest prior art need not be explicitly stated in the application, as long as it is derivable from the original application, in particular since the closest prior art may not have been known to the applicant when drafting it” (r. 5.3) This reasoning is in line with other interpretations of G 2/21, including T 0873/21 and T 0116/18. In T 2465/19, the Board of Appeal also construed the claimed feature differently to the ED in view of the application as whole. Following this construction, the Board of Appeal concluded that the feature was not an arbitrary selection, did in fact have an advantageous effect (r. 5.4) and provided an alternative solution on the basis of which inventive step could be acknowledged (r. 5.6).

In this case, it was necessary for the applicant to demonstrate that the feature distinguishing the claimed invention from the prior art had an advantageous technical effect in view of the closest prior art. However, it was not necessary for this technical effect to be recited in the application as filed. The technical field of the invention was also such that experimental evidence of the technical effect need not be provided. As characterised by the Board of Appeal itself, the technical effect could be as straightforward as an alternative solution semiconductor that was “easier to manufacture” (r. 5.5).

Final thoughts

Despite being oft characterised as such, G 2/21 was not really about plausibility (IPKat). By focusing on the disclosure requirement for the technical effect, G 2/21 has become relevant to any patent wishing to rely on an advantage for inventive step that was not disclosed in the application as filed. G 2/21 also arguably did not add much, if anything, to the question of what is the appropriate standard of evidence for inventions in challenging technical fields. Unlike in the UK, the sufficiency requirement remains a low bar for a product claim (IPKat). It also remains necessary to provide some evidence (although less than might commonly be expected) in order to support a claim for a therapeutic use, in view of the higher level of doubt with regards to this type of invention (T 1394/21). Furthermore, providing enough evidence for a purported technical effect for inventive step at the EPO continues to be more challenging in certain technical fields for which there is a lot of potentially relevant prior art such as therapeutic antibodies and machine learning algorithms. G 2/21 did not change the law on any of these issues. 

As interpreted by the Boards of Appeal so far, what G 2/21 did do was to clarify that a technical effect relied on for inventive step does not need to be disclosed in the application as filed (Cf. EPO Guidelines for Examination, H-V, 2.2). This point of law is relevant to any invention. In fact, with regards to disclosure requirements of a technical effect, the case law on this topic may primarily be derived from the software field, where the question is more whether any technical effect of the invention is derivable from the application as filed. We have, by this point, come a long way from "plausibility". 

Further reading

• Plausibility demystified - a review of EPO case law before G 2/21 (Feb 2023)
• G 2/21: Is the technical effect embodied by the invention as originally disclosed? (March 2023)
• UK divergence from the EPO on plausibility (Sandoz v BMS), Part 1: Is the "plausibility" test the same for both sufficiency and inventive step? (July 2023)
• UK divergence from the EPO on plausibility (Sandoz v BMS), Part 2: Interpretation of G 2/21 (July 2023)
• Chocolate teapots and nuclear bombs: Whole range sufficiency of mechanical inventions (T 0149/21) (July 2023)
• The relevance of G 2/21 to machine learning inventions (T 2803/18) (Aug 2023)
• Interpretation of G 2/21: Inventive step may be supported solely by post-published data (T 0116/18) (Sep 2023)