G 2/21 does not permit armchair inventing (T 0258/21)

Interpretations of G 2/21 by the EPO Boards of Appeal have so far been reasonably patentee-friendly. Boards of Appeal have interpreted G 2/21 as permitting patentees to rely on technical effects for which the application as filed is completely silent (IPKatIPKat). The recent decision in T 0258/21, by contrast, is the first interpretation of G 2/21 leading to a finding of a lack of inventive step in view of an inadequate disclosure of the purported technical effect. However, T 0258/21 related to subject matter for which the EPO has always required additional evidence. Particularly, the claim in question was directed to a second medical use of a known therapeutic in a subpopulation of patients. The Board of Appeal considered there to be a complete lack of any convincing supporting data for the claimed use, either post-published or in the application as filed. The decision in T 0258/21 is therefore not surprising, and confirms that whilst G 2/21 is broadly favourable to patentees, it does not permit armchair inventing. 

T 0258/21Case background

T 0258/21 related to the EP patent application EP 12716828.4. The application claimed clevidipine for the treatment of ischemic stroke. Clevidipine is a anti-hypertensive drug marketed by Chiesi as Cleviprex. The closest prior art was identified as a journal article mentioning the use of clevidipine for the treatment of haemorrhagic stroke. The difference between the claimed invention and the closest prior art was identified as being that the invention related to ischemic stroke instead of haemorrhagic stroke. Importantly, ischemic and haemorrhagic strokes have very different causes. Ischemic strokes are caused by blood clots blocking the supply of blood to the brain. Haemorrhagic strokes are caused by a ruptured blood vessel in the brain. 

Rather surprisingly for a medical use application, the application itself did not contain any data relating to the therapeutic effect. The original application was no more than 20 pages in length and didn't include any data, examples or figures. In view of this rather sparse disclosure, the Board of Appeal concluded that "[n]o technical effect directly linked to the identified distinguishing feature, namely the reduction of ischemic stroke damage, has thus been demonstrated in the application documents". 

Reliance on a post-hoc identified technical effect of medical use in the absence of any data 

Armchair inventing
On appeal, the applicant argued that the selection of clevidipine for the treatment of ischemic stroke was inventive in view of the unexpected technical effect of clevidipine for the treatment of ischemic stroke. Particularly, the applicant argued that clevidipine was surprisingly safe and efficacious in the treatment of ischemic stroke compared to other anti-hypertensive agents. The applicant submitted post-filed data purporting to support this technical effect. 

However, the Board of Appeal was not convinced that either the application as filed or the post-filed data adequately supported the technical effect proposed by the applicant. First, with regards to whether it was even possible for the applicant to rely on the post-hoc technical effect, the Board of Appeal noted the order from G 2/21 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". 

For the Board of Appeal in the case in question, the technical effect on which the applicant was seeking to rely "was neither contemplated nor even suggested in the original application. Indeed the original application did not mention any comparison to other anti-hypertensive agents and it encompassed the treatment of both haemorrhagic and ischemic stroke [...]. It follows that this technical effect relied upon by the applicant cannot be taken into account for the assessment of inventive step in accordance with G 2/21." The Board of Appeal also noted that even if the purported technical effect could have been derivable from the original application, the additional submissions from the applicant purporting to support the technical effect did not "provide any detailed results nor any details on the protocols used [...] The meaningfulness of the appellant's exploitation of the data provided in these abstracts is therefore prima facie questionable."

The Board of Appeal was thus not convinced that the technical effect on which the applicant wished to rely on for inventive step was convincingly encompassed and embodied by the application as filed. The Board of Appeal went on to conclude that, in the absence of a surprising technical effect derivable from the application as filed (or even the post-filed data), it would be obvious in view of the prior art for a skilled person to select clevidipine for the treatment of ischemic stroke. 

The applicant also found themselves in an inventive step / sufficiency squeeze in their attempt to argue that the prior art did not plausibly demonstrate the use of clevidipine to treat ischemic stroke: 

"the Board underlines that, should the appellant's unpredictability approach have been followed (i.e. the effect of clevidipine in the treatment of ischemic stroke damage in patients with ischemic stroke not be considered plausible on the basis of [the prior art]), an issue of lack of sufficiency of disclosure would have arisen since the original application does not provide any experimental data substantiating the claimed medical use."

The Board of Appeal thus upheld the decision of the Examining Division to refuse the application. 

Final thoughts

The implementation of G 2/21 in this case could be said to contrast with previous decisions, in which G 2/21 has not been interpreted as preventing applicants from relying on a technical effect on which the application as filed is completely silent (IPKat). However, none of the previous decisions interpreting G 2/21 have contemplated the evidence requirement for a technical effect for a biotech invention for which no supporting data or statements could be identified from any of the application as filed, common general knowledge (absent an obviousness squeeze) or post-published submissions.  

It is not a surprise that a second medical use claim may be refused by the EPO in view of the complete absence of any data, either in the original application or submitted post-filing, supporting the medical use. As has been discussed extensively in the context of the plausibility debate (IPKat), second medical use inventions represent a class of invention where there is additional burden on the patentee to provide supporting evidence. In most cases, there will be substantial doubt over whether any particular substance or composition will be safe and efficacious at treating a particular disease, hence the need for long and protracted clinical trials and regulatory processes. It is therefore not surprising that patent offices require some evidence to support a medical use claim. G 2/21 has not changed this requirement. 

Further reading

Image credit: DALLE-3

G 2/21 does not permit armchair inventing (T 0258/21) G 2/21 does not permit armchair inventing (T 0258/21) Reviewed by Rose Hughes on Tuesday, October 31, 2023 Rating: 5


  1. Forgive me for not giving a well-researched comment, but briefly T1385/15 referrred to G 6/88 saying the guiding principle was as follows:

    “A claim directed to the use of a known substance for a particular purpose, which is based on a technical effect described in the patent, is to be interpreted as containing this technical effect as a functional technical feature; such a claim is not open to objection under Article 54 (1) EPC, if this technical characteristic has not been made available to the public before.”

    This is a very important for interpretation of medical use claims. i.e. the achievement of therapy is directly linked to contribution and distinguishing over the prior art. Therefore it is not surprising that G2/21 is going to have a very limited effect in making things more lenient for therapy-related inventions. The demonstration of achievement of therapy is an important aspect of technical effect and sufficiency for a medical use claim, and the system would break down if that was changed.

  2. I have a few questions which I want your excuse if they are very basic questions.

    First, where the technical effect is claimed in the application (eg. second medical use claims) the issue of plausibility of this technical effect should be assessed under the sufficiency of disclosure. But in this case why the technical board considers it under the inventive step?

    And second, if the “objective technical problem” is constructed in light of the technical effect which patent applicant mentions somehow in the application then how can be the technical problem “objective”? Because his invention is already described in the claims, should the meaning of the “invention” and “inventiveness” be an objective one? Sometimes I found some similarities between the “conception” on which US inventor concept based before AIA and the requirement of pointing the technical effect in the patent application.

    1. Perhaps the thought helps, that a contribution to the art is potentially patentable whenever it is "A difference that makes a difference". You have novelty as soon as there is "a difference". But mere novelty isn't enough. You need also an inventive step. And to assess whether that is present, you need to enquire what difference the novelty makes.

      And in any First to File jurisdiction, the difference that the difference makes has to be derivable from the application as filed.

      Second medical use is particularly tricky to adjudicate. Only a few people argue that if the application fails to present the results of clinical trials then it is fatally premature, filed too early to be valid. But if not clinical trial results, what data is enough to substantiate a valid patent application and differentiate it from an armchair invention? Hard to say, isn't it? How about "is it plausible"? What better yardstick is there, out there?

    2. Hi Anonymous of Wednesday, 1 November 2023 at 06:51:00 GMT. Whilst these are interesting questions, what would be your answers to the questions? It would be interesting to see whether your perspective is one more akin to theory and jurisprudence or whether it concerns EPO case law. Thank you

    3. As to the first question, Art.83 would apply to the plausibility of the functional feature that is recited in the claim, i.e. "reducing ischemic stroke damage in a subject with an ischemic stroke" in T 0258/21 (and equally, "effective amount" and "half-life in plasma of less than 30 minutes"). The reasoning of the Board in point 1.3.2 concerns the technical effect asserted by the applicant, namely "an optimal balance of efficacy, precision (titrability) and safety". That technical effect is not recited in the claim and hence is treated under Art. 56 (see G2/03 r.2.5.2). Furthermore, G 2/21, r.74 applies only to the effect that is recited in a second medical use claim, not to other technical effects that are invoked by the applicant/proprietor in favor of inventive step of a second medical use claim.

    4. As to the second question, the term 'objective technical problem' is not in itself a hard rule and the EPO in fact applies a balanced approach. The problem must be objectively solved by the claimed subject matter compared to the closest prior art/starting point document (T20/81). On the other hand, a purely objective approach does not work well in the field of chemistry, where patent applications with only compound claims and only disclosing new compounds and their preparation, without indicating any use, do not serve the technology dissemination purpose of patent publications well (I understand this was an episode from the German national case law). G2/21 confirms that the EPO applies a balanced approach by requiring that the application as filed provides sufficient support for the technical effect in the application as filed (my analysis is that G 2/21 leaves the height of the threshold open to the Technical Boards of Appeal to decide in each case but for saying the threshold can not be zero).

    5. Dear Peter,
      These are really explanatory and informative answers, thank you for your kindness!

    6. Dear Mr. Peter,

      As far as I am aware, although the invention is not in the field of the chemistry still the applicant requires to show the technical effect.
      For example in the 1924/20 decision the Technical Board of Appeal rejected examining the inventive step based on a technical effect (i.e. reducing the possibility of moisture reaching the technical modules of the hearing aid machine) explicitly stated by the patentee in the description of patent. However, the applicant/patentee should rely on a technical effect in the assessment of the inventive step if this effect is encompassed and embodied by the technical teaching of the “application” (G 2/21). However in the 1924/20 decision (https://ipkitten.blogspot.com/2023/04/construing-claims-to-include-technical.html), Board of Appeal did not consider the issue in this respect but rejected this technical effect just because the description cannot be used in construing the claims. As far as I know, there is no necessity that the technical effect be specifically stated in the claims unless the invention is not e.g. second medical use invention. Could it be concluded there are inconsistencies between T 1924/20 and other decisions in this regard. Would the result be different if the description have provided some evidence and precise results about this effect is achieved by the invention (i.e. the technical effect is explicitly "plausible").

    7. As to T 1924/20, I personally find the decision a bit obscure, but my analysis is that the Board considered that the explicit features of the claims did not yield the asserted technical effect and did not accept the argument of the proprietor that the claim was implicitly limited to the embodiments that gave the asserted technical effect.
      G 2/21 in my view does not alter the existing, separate, requirement that a technical effect should also be sufficiently proven to be actually achieved over the whole scope of the claim, T 939/92, see r.26 of G2/21 in particular.

  3. On another blog, dated today, is a report on T1752/19, also a second medical use case.

  4. As to why the Board examined the issue under Art. 56, good question indeed. It is puzzles me.


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