Introduction
Background
Facts
Referral
Comment
The Board of Appeal of the European Patent Office (EPO) has referred questions to the Enlarged Board of Appeal (EBA) on the relevant plausibility standards for European patents in the case T 116/18.
As the EBA is the final arbiter on interpreting the European Patent Convention (EPC), the answer to the questions referred will be important in determining what evidence a patent applicant must include in the patent application as filed, and to what extent evidence published after a patent application has been filed (ie, post-published data) can support claims made about the inventiveness of the process or product covered by the application. As a result of the referral, the EPO has now stayed all examination and opposition proceedings in which the decision depends entirely on the outcome of the referral.
Ultimately, this will be key in helping applicants to determine when to file their patent applications. This is important in all sectors but particularly in respect of life sciences, where filing at the correct time can have a bearing on successfully securing much-needed funding for start-up companies and small and medium-sized enterprises.
The concept of "plausibility" in patent law is not a requirement under the EPC but has emerged from EPO case law and has been followed and developed further by the national courts.
To demonstrate that their inventions are patentable, applicants must, among other things, show that an inventive step has been taken that advances the known art and that is not obvious to a person skilled in that art. At the EPO, this is assessed by reference to the so-called "problem-solution test".
Under that test, an applicant may rely on a particular technical effect attained by the invention to establish inventive step. Such effect must be supported by data.
The EPO has developed the concept of "plausibility" to avoid purely speculative patents being granted. When the applicant relies on a particular technical effect to establish inventive step, that effect must be plausible at the date the patent was filed. A question that arises then is whether the supporting data must be included in the application or whether additional, post-published data can be filed during examination, post-grant opposition or even litigation.
The patent in T 116/18 is in the field of phytosanitary products and relates to an insecticide comprising thiamethoxam and a compound having "formula 1a". The difference between claim 1 and the prior art was identified as the selection of the combination of thiamethoxam and formula 1a. The patentee (Sumitomo) alleged that the technical effect of the selection is said to be synergy between thiamethoxam and compounds falling under definition of formula 1a.
The patent included examples testing the interaction between thiamethoxam and various compounds of formula 1a. During appeal proceedings, Sumitomo provided post-published documents that contained further data showing the claimed synergy between thiamethoxam and compounds of formula 1a. The opponent (Syngenta) argued that the effect of synergy between thiamethoxam and compounds of formula 1a had not been made plausible in the application as filed – in other words, there was no data in the patent specification to support the alleged synergistic effect of the claimed combination across the entire scope of the claim.
Therefore, Syngenta argued that post-published documents could not be taken into account. The Board of Appeal concluded that the admittance or not of the post-published evidence was decisive for inventive step.
Case law
The Board of Appeal considered that different lines of EPO case law in respect of plausibility and the admissibility of post-published evidence have arisen.
According to a first line of case law, post-published evidence is admissible if the technical effect is made plausible based on data in the patent as filed. The effect is deemed plausible if, on the basis of data in the patent specification and its common general knowledge, the skilled person would have had reason to assume the purported technical effect to be achieved. According to this line of case law, it is only if the applicant has succeeded in demonstrating the plausibility of the alleged technical effect that it can rely on further, post-published data. This requirement is referred to by the Board of Appeal as "ab initio plausibility".
However, in some cases, the EPO has adopted a slightly different, more flexible approach to plausibility.
A second line of case law has applied a test that the Board of Appeal referred to as "ab initio implausibility". Under this test, post-published evidence is always admissible unless the skilled person at the filing date would have had legitimate reasons to consider that the purported technical effect was implausible (ie, that it would not have been achieved).
In a third line of case law, post-published evidence has been accepted without a plausibility requirement, on the basis that an applicant cannot be reasonably expected to include all experiments and scientific evidence for all of the technical features of the invention in the patent application.
The Board of Appeal considered that there is a tension between the different lines of case law. It said that the ab initio plausibility (the first line of case law) and no plausibility (the third line of case law) lie at different ends of the spectrum, with the ab initio implausibility standard (the second line of case law) lying somewhere in between the two extremes.
This also highlights the difficulties of adopting either extreme standard: the ab initio plausibility standard would provide a high bar to overcome, with only very narrow patents, which contain data within the application as filed that makes the invention plausible, being granted. In contrast, if the no plausibility standard is applied, it runs the risk of speculative, so-called "armchair" patents, with no supporting data, being granted.
Inventive step or sufficiency?
One possible explanation for the divergence in the EPO case law is the preference of the EPO to consider plausibility in the context of inventive step as opposed to under the ground of sufficiency. For example, the requirement for the technical effect of a claimed invention to be rendered plausible in the application as at the date of filing is incompatible with the problem-solution approach for inventive step.
Currently, in proceedings before the EPO, it is the case that if the technical effect claimed by a patent is not defined in the patent claims, the EPO will consider whether it was nevertheless plausible, based on the information at the disposal of a skilled person at the time of the filing, and enough to satisfy the requirement of inventive step. If the technical effect is defined in the claim, the EPO currently considers plausibility in relation to the sufficiency requirements.
As a consequence of the different lines of case law and the need for uniform application of the law, the need for clarification is clear. The Board of Appeal, in its preliminary opinion, therefore referred a number of questions on plausibility and post-filed evidence to the EBA.
The final questions referred to the EBA are as follows:
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):
- 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?
- 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)?
- 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)?
It seems a little surprising, perhaps, that the Board of Appeal did not refer any questions concerning whether plausibility should be considered in relation to inventive step or sufficiency, and it is therefore likely that this issue may ultimately need to be considered.
In making the referral to the EBA, the Board of Appeal considered the UK Supreme Court's decision in Warner-Lambert v Generics t/a Mylan.(1) In this case, the Supreme Court considered the concept of plausibility in relation to whether the technical effect claimed by a patent had been disclosed sufficiently clearly and completely – under the umbrella of sufficiency as opposed to inventive step. The Supreme Court confirmed that, in the context of sufficiency, post-filed data supporting the technical effect can be considered, but only if it has been made plausible from the information in the application as filed that the technical effect could be expected.
Interestingly, the Board of Appeal considered that, in Warner Lambert, the majority applied the ab initio plausibility standard. The Board of Appeal further commented that the minority applied the ab initio implausibility standard. However, as well as considering plausibility in respect of sufficiency rather than inventive step, the Warner-Lambert case related to second medical use patents, and therefore there is some debate as to whether this applies more widely, and similarly, whether it can be used by the EPO in the present proceedings as an effective comparison.
The referral of T116/18 to the EBA should provide patent applicants with greater clarity in relation to how much data is needed to support a patent application and when the relevant data needs to be available (ie, at the date of filing or as post-published evidence).
This is important because it feeds into the key question of when to file, and how much data is required to support an application. This is particularly important in the life sciences sector with small start-ups needing to demonstrate patent filings to support funding applications.
The importance of the referral is underlined by the fact that the EPO has now suspended all examination and opposition proceedings in which the decision depends entirely on the outcome of the referral – that is, patents and applications in which the assessment of inventive step is exclusively based on post-published evidence.
From a patent practitioner's perspective, it will be interesting to see how or whether the EBA seeks to reconcile the various approaches to the question of plausibility in the EPO case law, or whether the EBA will carve its own path.
The EBA is not expected to rule on this matter for at least a couple of years, meaning that national courts are likely to have to grapple with the issue before then. This has the potential, of course, to lead to diverging case law. However, the fact that the EBA considered the UK Supreme Court decision in Warner Lambert perhaps indicates that there is more of an appetite to clarify and align case law across European jurisdictions.
For further information on this topic please contact Sarah Taylor or Anna Harley at Pinsent Masons by telephone (+44 20 7418 8250) or email ([email protected] or [email protected]). The Pinsent Masons website can be accessed at www.pinsentmasons.com.
Endnotes