Sufficiency has long been an accepted requirement for any patent application made within member nations of the World Trade Organisation (WTO). Whether one meets this standard, as well as that of the less rigidly defined concept of plausibility, will depend on the type of invention. Here, we provide an overview of the concepts of sufficiency and plausibility and discuss how two key judgments could affect future patent applications.
What is sufficiency of invention?
To fulfil the practical application of an invention, a patent application is legally required to disclose enough detail to ensure that a person skilled in the art will be able to make and use the invention.
Enshrined under Article 83 (‘Sufficiency of disclosure’) of the European Patent Convention (EPC), this requirement is part of the legal exchange inherent in a successful patent application. That is: you are granted a temporary monopoly on an invention, in return for fully disclosing how it works.
According to the European Patent Office’s (EPO) general guidelines, an invention’s description must disclose “any feature essential for carrying out the invention in sufficient detail to make it apparent to the skilled person how to put the invention into practice”, without “undue burden” or “needing inventive skill”.
An example of the invention as it is described in the application will usually suffice. The amount of detail required, however, can vary depending on the type of invention and whether there is a higher level of doubt concerning its functionality and effectiveness.
In such cases, the EPO will apply the concept of ‘plausibility’ to address the greater degree of uncertainty.
What is plausibility?
Certain inventions require more substantial evidence to adequately address the higher degree of doubt over whether an invention can achieve its purported technical effect and, therefore, meet the ‘inventive step’ requirement for patentability under Article 56 of the EPC.
This is often the case for therapeutic or diagnostic applications, which often come with greater scepticism over whether a randomly chosen compound or method can achieve the desired technical effect, for example.
Plausibility is not a distinct legal standard under the EPC, but it has been established by case law. It is essentially a criterion for assessing whether a purported technical effect can be relied upon to support an argument for inventive step. This will often involve reviewing any accompanying evidence or technical data to establish if it adequately supports the application’s claims.
Can I submit additional data to improve my application’s plausibility?
This is a complex area of patent law and one for which advice should always be sought.
As a general rule, a patent application will be reviewed as filed, with supplemental data and information ignored and discarded. This prevents the submission of ‘speculative’ patents.
That is not to say that there will always be a point-blank refusal of ‘post-filed data’, however.
The Enlarged Board of Appeal’s judgment in G2/21, for example, states that post-published evidence can, in certain circumstances, be submitted to support plausible effects. Having said that, the judgment also reiterated that the concept of plausibility is primarily used to evaluate the credibility of the claimed technical effect on the application as filed.
T 0589/22 expands on this stance, with the Board of Appeal ruling that post-published data could not rescue a patent that was refused on grounds of insufficiency. See the box-out below for a more detailed analysis of this key judgment.