When does an application fail the controversial new EPO plausibility test?

News | 25.10.2023

When does an application fail the controversial new EPO plausibility test

European patent attorneys are still grappling with the meaning of the new standard for relying on post-published data for inventive step laid down in plausibility decision G 2/21. Here our London Partner Adam Lacy and Munich Partner Stephan Disser review T 258/21, which is the first decision to apply the new test to conclude that new data cannot be relied upon.
G 2/21 headnote point II held 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.
The wording of this test left many questions unanswered, as discussed here. T 258/21 helps EPO users understand how the Boards of Appeal might apply the test going forward, by giving an example of when the test is not met. The application and claim at issue related to Clevidipine for use in a method of reducing ischemic stroke damage (ISD), but the application included no evidence that this medical use was in fact achieved (see reason 1.3.1) 
Despite the lack of evidence, the medical use of reducing ISD was not considered insufficiently disclosed due to the teaching in the closest prior art showing that this agent can be used to treat another type of stroke (reason 1.4.3). However, applicant wasn’t allowed to use new data to show that Clevidipine delivers improved activity and reduced side-effects compared to other antihypertensive agents in treating ISD. This effect was, according to the Board, not “derivable”, although “activity” and absence of “side effects” are mentioned in general terms in the application as filed:
...the Board notes that this effect 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 hemorrhagic and ischemic stroke (see e.g. original page 3, second paragraph). 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. Moreover, even if said technical effect would have been derivable from the original application…

Although the Board’s conclusion might be useful when faced with a similar pattern of facts, unfortunately the decision isn’t particularly clear on how exactly the test is applied making it difficult to draw general conclusions. 

What can be said is that the Board interprets “derive” in the G 2/21 test as “contemplate” or “suggest”. Meanwhile, “encompassed by the technical teaching” in the test doesn’t seem to stretch to situations where the effect is a subset of one mentioned, i.e. the treatment of a specific type of stroke where others were discussed at a general level in the application as filed. That said, it is possible that the case fails the “embodied by the same originally disclosed invention” limb of the test instead – unfortunately the decision isn’t particularly clear on this.
In our view, this decision is significant as it is the first to conclude that new data can’t be relied upon. It is limited though in the sense that it doesn’t provide detailed explanations on how the Board actually applied the test. We hope that slowly, through the development of the case law, the meaning of the controversial test in G 2/21 will begin to emerge to improve legal certainty on this important point in Europe. We are keeping our fingers crossed and eyes peeled.