Is the description of a European patent worth the paper it is written on?

Enlarged Board of Appeal referral G1/24 has arisen due a divergence in case law concerning the role of the description in interpreting the claims of a European patent. This article explores the effect that the Enlarged Board’s ruling may have on the question of whether the description of a European patent should be amended for conformity with the claims.

The European Patent Office (EPO) has wasted a lot of ink in recent years considering the role of the description of European patents without getting any closer to clarity on this issue. On the one hand the EPO Examiners are fixated on arriving at a description that is in full conformity with the claims, whereas on the other hand some EPO decisions ignore the contents of the description when interpreting the claims. In accepting a referral of questions concerning the role of the description in interpreting the claims, the Enlarged Board of Appeal, the EPO’s highest body that considers interpretation of points of law, has recognised the need for clarity on this matter. Their ruling has the potential not only to shape how the description is used to determine the scope of the claims, for example for the purpose of considering novelty; but also to affect the extent to which the description need be revised for consistency with the claims.

Background of the referring case

In case G1/24, questions about the role played by the description in interpreting the claims have been put to the Enlarged Board by Board of Appeal 3.2.01 to assist them in reaching a final decision in appeal case T439/22. That case concerns the validity of Philip Morris’ European Patent EP 3 076 804 concerning a device that generates a nicotine-containing aerosol rather than producing smoke through the combustion of tobacco as in a conventional cigarette. A key issue is whether the “gathered sheet” referred to in claim 1 is also present in the cited prior art documents.

The first instance Opposition Division considered that the term “gathered sheet” has a clear and agreed meaning widely understood in the tobacco industry to require sheets that are both "folded and convoluted". As the sheets in the prior art are convoluted but not folded, the claim is novel. In reaching that conclusion the Opposition Division ignored the definition of “gathered sheet” provided in the description of EP 3 076 804, to which the Opponent drew attention and which allowed for the sheet to be “convoluted, folded, or otherwise compressed or constricted" [emphasis added]. Under that broader interpretation the claim would have encompassed the non-folded configuration of a prior art device, and so lack novelty.

The relevant law

Article 69 of the European Patent Convention (EPC) states that “the extent of the protection conferred by a European patent … shall be determined by the claims. Nevertheless, the description … shall be used to interpret the claims.”. Many Boards of Appeal, and the Unified Patent Court in its decision 335/2023, consider that Article 69 EPC dictates that the description must be taken into account when construing the claims for the purpose of considering patentability. Under that approach, the term “gathered sheet” would need to be interpreted broadly and would thereby encompass the non-folded sheet in the prior art. However, another line of EPO case law says that as the claims take primacy, the description may only be referred to in exceptional circumstances where there is a need to clarify the wording of the claims. Following that approach the definition provided in the description must be ignored and the claims exclude the prior art.

The Questions Referred in G1/24

Board of Appeal 3.2.01 considers the case law of the Boards to be divergent on the following questions, which are all decisive for the case at hand:

1) What is the legal basis for construing patent claims for the purpose of patentability?

In particular, is Article 69 EPC be applied to the interpretation of patent claims when assessing the patentability of an invention or just for assessing infringement?

2) May the description and figures be consulted when interpreting the claims to assess patentability and, if so, may this be done generally or only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation?

and

3) May a definition or similar information on a term used in the claims which is explicitly given in the description be disregarded when interpreting the claims to assess patentability and, if so, under what conditions?

As pointed out by the referring Board, there is scope for undesirable consequences if a claim is given a different scope when assessing its validity compared to when assessing whether it is infringed. If the description is ignored when assessing the scope of the claims for validity purposes and hence the term is given its normal narrow meaning yet, when considering infringement, Article 69 EPC allows for the scope to be broadened in line with a definition in the description, a patent could be held valid over subject matter disclosed in the prior art and yet infringed by that same subject matter.

How is this Relevant to Description Amendments?

Clarity over the role of the description in interpreting the claims may also have wider implications for how the EPO treats the description during examination.

The G1/24 referral does not consider the question of description amendments directly. However, if the granted claims are to be interpreted as requiring the sheets to be both "folded and convoluted" despite a passage in the description that states they may be both "folded or convoluted", the decision may have a bearing on the practice of description amendments.

Need for conformity between the description and the claims

At present, the EPO’s Guidelines for Examination mandate that the description must be brought into conformity with the claims for the sake of the clarity of the claims. EPO Opposition Divisions likewise require descriptions to be adapted for conformity with claim amendments made post-grant. Some Boards of Appeal have questioned whether this is necessary - if the claims take primacy and the description cannot have any bearing on a claim that is clear per se what does it matter if the description is inconsistent with the claims? Put another way, if contradictory statements in description have no bearing on the scope of an already clear claim, then what is the legal basis for requiring the description to be brought into line with the claims?

On the other hand, if Article 69 EPC does have a bearing on the construction of a claim for the purpose of validity, then the contents of the description are of importance when assessing the scope of the claim and, as highlighted by the “gathered sheet” case discussed above, it is important that the description and the claims are in alignment.

A further referral on description amendments

In case T56/21 Board of Appeal 3.03.04 has indicated its intention to refer questions to the Enlarged Board as to whether the description need be amended to bring it into line with the claims. In its reasons for doing so, the Board has explored the need for greater clarity on the role of the description in interpreting the claims. For example, do discrepancies between the description and the claims mean that the scope of the claims is uncertain due to the operation of Article 69 EPC?

Interplay between these two issues

In the author’s view there is a clear link between these two issues.

If the claims are to be interpreted in light of the description, there is a logic in requiring consistency between the claims and the description. However, if the description has no bearing on how the claims are construed, the description has no effect on the scope or clarity of the claims and amendment of the description is entirely unnecessary.

Conclusions

Using words to define the scope of technical inventions is not an easy task. As recognised by UK judge Lord Hoffmann in Kirin Amgen Inc v Hoechst Marion Roussel [2004] UKHL 46 (point 34), the patentee is trying to describe something that is new and on occasion will need to depart from the conventional use of language. Defining a term in the description is a tool those drafting patents often use to resolve ambiguity or to clarify what they mean by the wording of the claims.

The answers to the questions referred in G1/24 could have a bearing both on how patents are drafted in the future and on the extent to which the description needs to be amended during examination and post-grant proceedings in Europe.

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