Gumming up a patent

Based on a number of judgments issued in France over the last couple of years, it seems that there has been a new trend towards the invalidation of patents due to extension of subject-matter. I have a feeling that, not so long ago, this used to be a ground of revocation that no one really took seriously outside of the EPO. And especially so in France, where there has been a long standing tradition of judges looking more closely at the description of a patent than at its claims, and coming up with their own definition of what the invention really is about, notwithstanding the exact wording used in the claims.

But as a famous singer once said, the times they are a-changin’, which brings us to the invalidation proceedings initiated by Normandy-based company Nexira against the British and Japanese owners of European patent EP 1611159. The patent relates to a modified gum arabic from Acacia senegal (that’s the scientific name of the tree from which the gum is collected). This gum can notably be used as an emulsifier in food products.

The main claim of the patent reads as follows:

A water-soluble modified gum arabic from Acacia senegal, having a weight average molecular weight of not less than 0.9 million Da or an arabinogalactan protein content of not less than 17 weight %, and an RMS-radius of gyration of 42.3 to 138 nm, obtainable by heating unmodified gum arabic at 110°C for not less than 15 hours, wherein the weight average molecular weight, arabinogalactan protein content, and RMS-radius of gyration are obtained by processing the data obtained by subjecting the modified gum arabic to a GPC-MALLS using software ASTRA version 4.5 and wherein said data for the whole peaks in the chromatogram obtained using an RI detector are processed as two peaks, the two peaks being divided into the eluted fraction of high molecular weight components containing the arabinogalactan protein of the gum arabic which eluted first and the eluted fraction of low molecular weight components which eluted at a later time, wherein the arabinogalactan protein content corresponds to the obtained recovery ratio of the peak of the eluted fraction of high molecular weight components which eluted first.

The crux of the discussion was the feature of the radius of gyration. The range of 42.3 to 138 nm was not disclosed per se in the application as filed; but the end values of the range were disclosed in the context of two respective examples.

The judgment does not explicitly refer to the case law of the Boards of appeal of the EPO. But there can be little doubt that the court relied on it, since they called this situation a case of “intermediate generalization”, which is typical EPO parlance. What is more, the standard put forward by the court for determining whether the intermediate generalization is admissible or not closely matches the test routinely applied in Munich. Said the court:

It is possible to generalize a range of values from an example, but such intermediate generalization is only admissible under Art. 123(2) EPC if the skilled person can deduce without any doubt from the application as filed that these features are not closely linked to other features of the embodiment, but that they directly and unambiguously apply to the more general context.

In order for this intermediate generalization to be admissible, it must result from the non-ambiguous information that the skilled person would derive by reading the example and the content of the application as filed.

Taking into account the whole content of the application, determining whether features isolated from the examples are closely tied to other features or not, and using direct and unambiguous derivability as a threshold: all European patent attorneys are familiar with these principles, as they are cornerstones of the assessment of extension of subject-matter by the Boards of appeal.

In the Nexira case, the outcome of the Court’s appraisal was negative:

In the present case, the skilled person could not deduce, without any doubt, when reading the international application, that these features, taken from two embodiment examples based on gum arabic having particular dimensions and composition, are not closely linked to other features of these embodiment examples, and directly and unambiguously apply to the more general context.

As a result, the addition of this range of radius of gyration RMS in claim 1 of the EP’159 patent whereas it was not in claim 1 of the international application, shows an extension of its subject-matter beyond the initial application.

How do you write "gum" in Arabic?
How do you write “gum” in Arabic?

Strictly speaking, it would have been interesting to get more detailed explanations in the decision as to why the radius of gyration in the examples should be viewed as being specific to the samples in question. One can also wonder about the relationship between the range of the radius of gyration and the other parameters recited in the main claim, such as the molecular weight, the protein content and the product-by-process features.

The question of who primarily has the burden of proof in this respect (the plaintiff or the defendant-patent proprietor) is also an interesting one which is not clearly addressed in the judgment –  as there was probably no reason for addressing it.

Anyway, the outcome of the case should not come as a real surprise: it is a risky gamble indeed to take values from an example section of a patent application and insert them into a claim. If the patent at stake had been subjected to opposition proceedings, chances are it would probably have faced a hard Art. 100(c) EPC challenge. The patent proprietors were lucky enough not to be faced with an opposition; but not lucky enough to get their patent tried by a court insensitive to EPO traditional case law.

This situation stands in sharp contrast with other French cases previously discussed here and here, where major deviations from EPO case law were observed, in connection with the issue of patent eligibility.


CASE REFERENCE: Tribunal de Grande Instance de Paris, 3ème chambre, 4ème section, Nexira v. San-Ei Gen FFI Inc. et al., May 28, 2015, RG No. 12/11963.

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