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T 1863/21 – Statistical significance of experimental data and assessment of sufficiency

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EP 2 575 508 B1 relates to an enteral composition containing a non-digestible oligosaccharide and a partial protein hydrolysate, which can induce oral immunological tolerance to the native proteins in the diet, in particular to milk proteins.

Brief outline of the case

The opposition was rejected and the opponent appealed.

The board held that the claims as granted lacked sufficiency, as did some ARs, but maintained the patent according to AR6.  

We will concentrate on the lack of sufficiency of the claims as granted.

The opponent’s point of view

Claims 1 and 2 had to be interpreted as being directed to compositions comprising a mixture of a partial protein hydrolysate and non-digestible oligosaccharides, the mixture exhibiting enhanced induction of oral tolerance.

There was no evidence that allowed the conclusion to be drawn that non-digestible oligosaccharide enhanced the partial protein hydrolysate’s ability to induce oral tolerance over the entire scope. A statistical analysis of the data furnished by the proprietor in D15 showed that a blend of galacto-oligosaccharides and fructo-oligosaccharides did not enhance partial protein hydrolysate-induced oral tolerance.

The proprietor’s point of view

Claims 1 and 2 had to be construed as being restricted to the oligosaccharides for use in enhancement of partial protein hydrolysate-induced oral tolerance against dietary proteins.

Examples 1, 3 and 4 of the patent and data in D15 demonstrated that the effect described in the patent and called for in claims 1 and 2 was achieved. Therefore, the invention was sufficiently disclosed.

The board’s decision

The OD and the proprietor interpret claims 1 and 2 as granted in a different way. Their interpretation does not focus on the aspect that a mixture is used but rather on the role of the non-digestible oligosaccharide. The role consists in enhancing the oral tolerance induced by the specified partial protein hydrolysates.

The patent’s examples are particularly relevant, starting with example 1, which relates to several sets of experiments carried out on mice.

The test set-up chosen in example 1 is suitable for demonstrating the enhancing role of non-digestible oligosaccharides.

Analogous results are shown also in examples 3 and 4 of the patent. These confirm the findings in example 1. A visual inspection of the figure in D15 also confirms the results of example 1 of the patent.

The opponent disputed that such an effect was achieved when only one or two non-digestible oligosaccharides were used. For the opponent, the result was not achieved over the entire scope of claims 1 and 2.

The opponent’s line of argument was based on a statistical analysis of the results shown in the figure of D15.

For the board, statistical significance is not and should not be the sole criterion for considering experimental results, let alone for excluding them from consideration.

 In T 884/06, Reasons 17, the entrusted board concluded that the effect under scrutiny was demonstrated “even though the actual statistical significance might be arguable“. The present board, in a different composition, decided in T 299/18, Reasons 3.6.7, that the data in the contested patent underlying that decision did not necessarily have to “show a statistically significant difference that stands up to strict, mathematical scrutiny of the data”. After all, a patent need not fulfil the standards that a peer-reviewed scientific publication might have to comply with.

Indeed, the present board subscribes to the view expressed in the Catchword of T 2036/21, by this board in a different composition, that the principle of the free evaluation of evidence applies universally in proceedings before the EPO when assessing any means of evidence.

The deciding body decides in the light of its own conviction, taking into account the evidence available in the proceedings and on the footing that one set of facts is more likely to be true than the other.

In proceedings before the EPO, it is thus not a prerequisite to perform a statistical analysis of the results and to determine a specific confidence interval in order to consider a certain piece of evidence convincing, as it is most often required in biomedical research and by health authorities granting marketing authorisations for medicinal products.

Statistical significance quantifies the probability that an observed difference in data is not a random occurrence. Hence, the allegation of lack of statistical significance does not in itself prove the null hypothesis, i.e. the hypothesis that there is no difference between groups, or no effect of a treatment. This is explained in detail in a document that discusses the relevance of statistical significance when reporting on crucial effects in scientific publications.

Therefore, lack of statistical significance does not automatically render a demonstrated effect implausible for the purposes of a legal assessment. Similarly, classifying a data point as an outlier is simply a statement on the probability that the data point is not a true member of the data set. In the current case, this in itself is not sufficient to set aside and disregard the remaining results.

The opponent would have had to raise serious doubts that the invention is not sufficiently disclosed over the entire scope. Under the circumstances of the present case, and in view of the patent’s examples, the opponent’s finding on the statistical relevance of the data in D15 is not sufficient to raise doubt that can be qualified as serious.

The experiments in the patent show that the at least one non-digestible oligosaccharide provides enhancement of the oral tolerance obtained by the specific partial protein hydrolysate.

The claim referred to oral tolerance against dietary proteins but the protein fragments defined in the claim could only generate oral tolerance against milk proteins.

For the board, it is clear that the partial protein hydrolysates to which claim 1 is restricted are not suitable for inducing oral tolerance against any dietary protein. The partial milk protein hydrolysates of claims 1 and 2 provide oral tolerance only to the corresponding intact protein, i.e. milk protein.

In this respect it is manifest that claim 1 is not sufficiently disclosed over the entire scope that it covers and for which protection is sought. Therefore, in view of this specific objection and only this specific objection, the board concludes that the invention is not sufficiently disclosed.


The present decision reminds us that in order to show lack of sufficiency serious doubts that the invention is not sufficiently disclosed over the entire scope of the claim have to be raised. The onus of proof lies with the opponent.

A mere statistical analysis of test results as it is most often required in biomedical research and by health authorities granting marketing authorisations for medicinal products is not necessary in order to show sufficiency in procedures before the EPO.

In the present case, the lack of sufficiency was due to the fact that claim 1 addressed hydrolysate-induced oral tolerance against any dietary proteins.

Claim 1 of AR 6 being restricted to oral tolerance against milk proteins as shown in the examples of the patent overcame the lack of sufficiency. It was also was novel and inventive over the available prior art.

It is further interesting to note that the board used the wording “not implausible”  for the purposes of a assessing a legal requirement. I would have thought that “plausible” and “not-implausible” were taboo since G 2/21.

Free evaluation of evidence is nevertheless a constant for deciding bodies at the EPO.  

The reference to milk proteins in the first sentence of the patent as well as the examples in the patent, showed that the effect of enhanced oral tolerance was only achieved for milk proteins and not for any dietary proteins. Those reasons were present from day 1 of the examination and later opposition procedure.

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