EPO Ruling On Claim Interpretation Will Have Broad Impact

1. Use of Descriptions and Drawings in Claim Interpretation: The Enlarged Board of Appeal decided that the description and drawings accompanying a European patent or patent application should always be consulted to interpret the claims when assessing patentability of the claims. This represents a change from the prior practice of typically referring to the description only when the claims are unclear.
   
   
2. Consistency Across Jurisdictions for Claim Interpretation: Guided by the harmonization philosophy behind the European Patent Convention, the decision aligns the European Patent Office's approach to claim interpretation with those of most national courts and the Unified Patent Court.
   
   
3. Implications for Patent Examination, Opposition, and Drafting: Patent practitioners should now take extra care to ensure alignment of the description and drawings with the intended scope of the claims, since changes to the former may directly impact how the claims are interpreted. However, care should always be taken to avoid accidentally adding subject-matter or inadvertently changing the scope of the claims.

On June 18, the Enlarged Board of Appeal of the European Patent Office issued an extremely concise decision in referral G 1/24, in a case involving Yunnan Tobacco International Co. Ltd. and Philip Morris Products SA.¹

In the decision, the Enlarged Board held that the description and any drawings included in a European patent or patent application shall always be consulted to interpret the claims when patentability of a claimed invention is examined at the EPO, and not only if the claims are found to be unclear in isolation.

Although decisions from the Enlarged Board are always of high importance, this particular decision is arguably one of the most significant in recent years.

Claim interpretation plays an important role in the assessment of validity and infringement of patents post-grant. However, the EPO has typically been reluctant to engage in matters of claim interpretation, with examining divisions in particular tending to take the broadest technically sensible definition of claim terms regardless of any relevant teaching found in the description.

G 1/24 brings EPO practice more into line with downstream forums, such as national courts and the Unified Patent Court, and will fundamentally change how the EPO interprets patent claims in both examination and opposition proceedings.

Background

As set out in Article 69 of the European Patent Convention, the extent of protection conferred by a European patent or a European patent application is determined by the claims. Article 69 goes on to state that the description and drawings shall nevertheless be used to interpret the claims.

On first inspection, it would be reasonable to question why a referral to the Enlarged Board was needed at all, given the apparently explicit instruction in Article 69 to use the description when interpreting the claims. However, Article 69 refers to "the extent of protection" and therefore arguably only applies to interpretation of the claims for the purposes of infringement, and not during patent prosecution.

A further reference to the relationship between the claims and description may be found in Article 84 of the EPC, which states that in addition to being clear and concise, the claims should be "supported by the description." Although this language implies some sort of relationship between the two, the extent of this relationship has long been debated.

Consequently, there has been a divergence in the case law of the EPO Boards of Appeal when it comes to claim interpretation. Some boards have held that the description should always be used to interpret the claims, whereas in others, the boards have seen fit to refer to the description only when the claims are found to be unclear in isolation — for example, to determine the definition of an unclear term or phrase during opposition proceedings.

These issues came to a head in the referring case, T 439/22 — an appeal by Yunnan Tobacco against the EPO Opposition Division's decision to reject Yunnan's opposition to Philip Morris' patent EP3076804.

In the referring decision, the Board of Appeal found that the novelty of the claims depended on how the term "gathered sheet" was interpreted. If the term were given its usual meaning in the art, the claims would arguably be novel. However, the description provided an alternative, broader definition for this term, which, if used when interpreting the claims, would arguably result in a lack of novelty.

Since the term "gathered sheet" was not considered to be unclear, the referring board concluded that the issue of novelty turned on whether the description should always be used to interpret the claims, or only in cases of unclarity.

The Board of Appeal in T 439/22 therefore referred three questions to the Enlarged Board:

1. Is the second sentence of Article 69(1) and Article 1 of the Protocol on the Interpretation of Article 69 to be applied on the interpretation of patent claims when assessing the patentability of an invention under Articles 52 to 57 of the EPC?
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?
3. May a definition or similar information on a term used in the claims and explicitly given in the description be disregarded when interpreting the claims to assess patentability and, if so, under what conditions?

The Decision

The Enlarged Board considered the first two questions to be admissible, first due to divergence in case law, and also due to both questions concerning a point of law of fundamental importance. Question 3 was found to be encompassed by the second question and was therefore found to be inadmissible.

Next, the Enlarged Board considered whether Article 69 and/or Article 84 provides legal basis for a particular approach to claim interpretation. In this regard, the Enlarged Board found that Article 69 and its protocol are arguably only concerned with infringement actions before national courts and the UPC, and that Article 84 addresses the content of the patent application and is formal in nature, providing no guidance on how to interpret claims.

The Enlarged Board therefore concluded that neither article provides an entirely satisfactory basis for claim interpretation when assessing patentability, and that the strictly formal answer to Question 1 would be no.

However, the Enlarged Board went on to note that, despite the lack of explicit basis in the EPC, this has not stopped some previous Boards of Appeal from extracting two general principles of claim interpretation, which may be applied more broadly:

1. The claims are the starting point and the basis for assessing the patentability of an invention under Articles 52 to 57.
2. The description and any drawings are always referred to when interpreting the claims, and not just in the case of unclarity or ambiguity.

The Enlarged Board agreed with these principles and therefore rejected the diverging case law of boards that saw no need to refer to the descriptions or drawings when interpreting claims unless the claims were unclear.

To justify its decision, the Enlarged Board noted that said diverging case law was contrary to the practice of the national courts of the EPC states, and to the practice of the UPC, which has been in operation since June 1, 2023. On this point, the Enlarged Board commented that it is "a most unattractive proposition that the EPO deliberately adopt a contrary practice to that of the tribunals that are downstream of its patents."²

That the UPC is adopting such an approach is evidenced by the March 11, 2024, UPC Court of Appeal decision in NanoString Technologies v. 10x Genomics,³ as well as the July 4, 2024, decision of the Paris Local Division in DexCom Inc. v. Abbott.⁴ In the latter decision, the court found that "the description and the drawings must always be used as explanatory aids for the interpretation of the patent claim and not only to resolve any ambiguities in the patent claim."

Before wrapping up, the Enlarged Board briefly discussed the effect of its decision on the assessment of a claim's clarity. The Enlarged Board headed off any suggestion that an unclear claim might be rendered clear by an appropriate reference to the description by firmly stating in the decision that the "correct response to any unclarity in a claim is amendment."⁵

Impact on Patent Practice

Claim interpretation is fundamental to the assessment of patentability, validity and infringement, and the decision in G 1/24 will therefore have many implications for practice. Some of the more notable implications that we foresee are as follows.

Examination Proceedings

Detailed discussions on claim interpretation are now likely to feature much more regularly in proceedings before the EPO, both during examination and opposition proceedings. Patent examiners in particular have tended to take the broadest technically sensible definition of claim terms, regardless of any relevant teaching found in the description.

It is clear from G 1/24 that this approach will no longer be acceptable, and applicants and patentees will have far more scope for arguing for a particular claim interpretation on the basis of the description when arguing patentability in both examination and opposition proceedings before the EPO. However, the Enlarged Board is clear in G 1/24 that if a lack of clarity is perceived, then amendment of the claims will still be required. Therefore, examiners may use this rationale to insist that the claims be amended to recite a particular definition where one exists in the description.

Practitioners should be mindful, though, that statements made on file regarding claim interpretation could have implications for related applications in other jurisdictions, particularly in the U.S. Practitioners thus need to exercise care when making such arguments.

Another aspect of examination proceedings that may be affected is the EPO practice of requiring amendment of the description prior to grant to align with the allowed claims. It seems probable that the decision in G 1/24 will serve to reinforce the EPO's approach here given the now increased importance of the description. Thus, any practitioners hoping for a relaxation of the EPO's approach to description amendments, of which there are many, are likely to be disappointed.

In addition, the importance of carefully considering whether amendments to the description may change the meaning of a claim, and therefore potentially add subject matter, will only increase. For example, deleting portions of a description or drawings that impart a particular interpretation to a claim term could leave the patent in an inescapable added-matter trap if reintroduction of the deleted portions post-grant, such as during opposition proceedings, would lead to a shift or broadening in the claim scope.

Opposition Proceedings

In inter partes proceedings, depending on the circumstances, there may be scope for both proprietors and opponents to rely on G 1/24 to support a particular claim interpretation.

Although the referring decision turned on the use of the description by an opponent to argue for a broader interpretation of the claims, it is inevitable that proprietors will rely on G 1/24 to argue for narrower interpretations of their claims based on the description when it is advantageous to do so, for example, when attempting to argue novelty.

Thus, as in examination proceedings, arguments regarding claim interpretation are likely to feature more frequently and have a greater influence on the outcome of opposition proceedings.

Patent Drafting

At the drafting stage, practitioners should now take extra care to ensure that the description and drawings are consistent with the intended claim scope. In particular, if the description and drawings imply a particular interpretation of a claim term, either explicitly or by suggestion, this may now prevail during proceedings before the EPO, and it may prove difficult to argue otherwise if circumstances change.

On the other hand, the drafter now has a greater freedom to impart a particular interpretation to a term used in the claims by including definitions and examples in the description.

However, the Enlarged Board has made it clear that claims will still need to be clear in of themselves, and there are likely to be limits to how far a claim term can be defined by reference to the description and drawings. Therefore, where possible, claims should still be drafted so that the intended meaning is clear from the claims in isolation, as well as consistent throughout the claims.

Conclusion

The Enlarged Board's decision in G 1/24 brings the EPO's approach to claim interpretation more in line with that used by downstream national courts and the UPC. This should lead to more consistency between decisions on patentability and validity taken by the EPO and downstream courts, providing greater certainty for both patentees and third parties alike.

However, practitioners need to be mindful of the wide-ranging implications of G 1/24 on everyday practice and should adapt their approach accordingly to take advantage of the opportunities that G 1/24 opens up while being alert to the potential pitfalls.

Footnotes

1 See G 1/24. https://link.epo.org/web/case-law-appeals/Communications/G_1_24_Decision_of_the_Enlarged_Board_of_Appeal_of_18_June_2025.pdf.

2 Reasons, point 16.

3 UPC_CoA_335/2023. https://www.unifiedpatentcourt.org/sites/default/files/upc_documents/576355-2023%20AnordnungEN.final_rectified.pdf.

4 UPC_CFI_230/2023. https://www.unified-patent-court.org/sites/default/files/files/api_order/8B08C53E1E2722DE9690B9C0BDAE0AEC_en.pdf.

5 Reasons, point 20.

Originally published by Law360

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