EPO Enlarged Board of Appeal confirms use of post-published data to support inventive step

On 23 March 2023, the EPO’s Enlarged Board of Appeal published its long-awaited decision concerning the evaluation of post-published data and the notion of plausibility (G 2/21).

The decision is significant because the EPO’s deciding bodies regularly employ the so-called ‘problem and solution approach’ to determine whether claimed subject matter involves an inventive step. One step of this approach requires the formulation of the objective technical problem underlying the claimed subject matter based on the technical effect achieved by the distinguishing features over the prior art.

To demonstrate such a technical effect, applicants often have to rely on post-published data, particularly in the fields of pharma and biotech. The development of new drugs and technologies in these fields is a lengthy and complex process. It typically involves multiple stages of testing, including preclinical studies and clinical trials, both of which can take years to complete. Applicants in these sectors regularly have to find a compromise between filing the patent application as early as possible and gathering data for demonstrating – or at least identifying – the advantageous effects.

For assessing whether post-published data can be taken into account for formulating the objective technical problem, EPO bodies frequently require that it must be ‘plausible’ from the application as filed – in combination with common general knowledge – that the purported technical effect was indeed achieved. However, the concept of plausibility has no statutory basis in the European Patent Convention (EPC) and was only introduced via case law of the Boards of Appeal. It has been a topic of controversy ever since.

Background of plausibility

The Technical Board of Appeal identified three divergent lines of case law (the concepts of ‘ab initio plausibility and implausibility’ and ‘no plausibility’) and thus referred the following questions to the Enlarged Board of Appeal.

If for acknowledgement of inventive step, the patent proprietor relies on a technical effect and has submitted evidence, such as experimental data, to prove such an effect, this evidence not having been public before the filing date of the patent in suit and having been filed after that date (post-published evidence):

1.         Should an exception to the principle of free evaluation of evidence (see e.g. G 3/97, Reasons 5, and G 1/12, Reasons 31) be accepted in that post-published evidence must be disregarded on the ground that the proof of the effect rests exclusively on the post-published evidence?

2.         If the answer is yes (the post-published evidence must be disregarded if the proof of the effect rests exclusively on this evidence), can the post-published evidence be taken into consideration if, based on the information in the patent application in suit or the common general knowledge, the skilled person at the filing date of the patent application in suit would have considered the effect plausible (ab initio plausibility)?

3.         If the answer to the first question is yes (the post-published evidence must be disregarded if the proof of the effect rests exclusively on this evidence), can the post-published evidence be taken into consideration if, based on the information in the patent application in suit or the common general knowledge, the skilled person at the filing date of the patent application in suit would have seen no reason to consider the effect implausible (ab initio implausibility)?

The board’s response

In the G 2/21 decision, the Enlarged Board of Appeal answered these questions.

1.         Evidence submitted by a patent applicant or proprietor to prove a technical effect relied upon for acknowledgement 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.

2.         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.

Further, the Enlarged Board of Appeal did not consider plausibility to be a distinctive legal concept or specific patent law requirement under the EPC. It deemed it to be a generic catchword only, seized in the jurisprudence of the Boards of Appeal by some national courts and users of the European patent system.

What G 2/21 means for applicants and practitioners

Overall, the decision appears to be good news for applicants that wish to (or must) rely on submitting experimental evidence generated or published after the application’s filing date (eg, scientific articles typically published after filing or comparative data generated in view of the prior art). As expected, the Enlarged Board of Appeal emphasised free evaluation of evidence as a universally applicable principle in assessing evidence under the EPC and decided that post-published data cannot be ignored.

While the Enlarged Board of Appeal avoids using the term ‘plausibility’, the G 2/21 decision is confirmation of the EPO’s current approach – it must be plausible from the filed application and common knowledge that the purported technical effect was achieved. Put simply, if an application does not mention or at least hint at a specific effect (eg, improved bioavailability of a compound or improved selectivity), such an effect cannot be invoked after filing. However, if an effect is mentioned or is plausible, then (further) data based on this effect may be submitted post-filing and will be evaluated by the deciding body.

Applicants are thus advised to include all available experimental data in their patent application and clearly specify the technical effects and advantages found. Following this decision, it will likely be problematic to merely include generic statements in which a technical effect is broadly claimed without specifying or quantifying it. In particular, omitting available data in a patent application for strategic reasons or filing it too early may still backfire and deprive the applicant from filing and relying on such data later on in the proceedings.