G 1/24: A New Era for Claim Interpretation at the EPO

The European Patent Office’s (EPO) top court (Enlarged Board of Appeal) has ruled that when deciding if a patent is valid, you must always look at the patent’s full description and drawings to interpret the claims, not just the claims on their own. This means patent drafters need to be even more careful to make sure everything in the patent application is consistent.

The EPO Enlarged Board of Appeal (EBA) has finally issued its highly anticipated decision in G 1/24 ("Heated aerosol") on 18 June 2025. This landmark ruling on claim interpretation is set to reshape patent prosecution and litigation across Europe, aiming for greater alignment between the EPO and national courts, including the burgeoning Unified Patent Court (UPC). As European patent attorneys, we've long navigated a complex landscape of claim interpretation, and this decision provides much-needed clarity, albeit with new considerations for our drafting and prosecution strategies.

Key Facts and Background to G 1/24

The Enlarged Board of Appeal (EBA) decision G 1/24 stems from a referral by a Technical Board of Appeal (TBA) in case T 439/22. The underlying patent in question is European Patent 3076804, held by Philip Morris Products S.A. This patent relates to "heated aerosol-generating articles," commonly known as "heat-not-burn" tobacco products.

The core dispute in T 439/22, which led to the referral to the EBA, centred on the interpretation of a specific term in Claim 1 of the patent: "gathered sheet."

The patent, EP 3076804, describes a heated aerosol-generating article (e.g., a "heat-not-burn" tobacco stick) for use with an electrically-operated aerosol generating device. A critical feature of Claim 1 was that the aerosol-forming substrate comprised a "gathered sheet" of aerosol-forming material (e.g., a sheet of tobacco) circumscribed by a wrapper.

The patent was opposed by Yunnan Tobacco International Co., Ltd. (YTI). The opponent argued that the patent lacked novelty due to prior art. Specifically, a prior art document (D1) disclosed a cartridge comprising a "spirally wound" sheet of aerosol-forming material.

Regarding the interpretation of the term “gathered sheet”, Philip Morris (the patent proprietor) argued for a narrow interpretation. They contended that if the term was assigned its usual, generally accepted meaning in the tobacco industry (implying specific configurations like folds or creases, which distinguish it from a simple "spirally wound" sheet), then their claimed subject-matter would be novel over the prior art. This aligns with what the Opposition Division initially found, which rejected the opposition.

YTI (the opponent), on the other hand, argued for a broader interpretation of "gathered sheet." They pointed to a specific definition provided within the patent's own description (e.g., paragraph [0035] of EP 3076804). This explicit definition, they contended, could encompass a sheet of tobacco that was merely rolled up into a cylinder – i.e., a "spirally wound" sheet as disclosed in the prior art. If this broader interpretation, derived from the description, was applied, then Claim 1 would indeed lack novelty.

This brought to light a long-standing and acknowledged divergence in EPO Technical Board of Appeal case law regarding claim interpretation, particularly when assessing patentability (novelty and inventive step).

One line of case law, often termed the "classical approach," held that if a claim term appeared to have a clear meaning when read in isolation, there was no need to consult the description or drawings for interpretation. The Opposition Division in T 439/22 adopted this view, concluding that "gathered sheet" had a clear meaning in the art and thus did not require consulting the broader definition in the patent's description.

Another line of case law (and increasingly, the approach of national courts and the UPC) favoured always consulting the description and drawings to interpret claims, regardless of perceived clarity in isolation. The referring Board in T 439/22 recognised this divergence and the fundamental importance of clarifying which approach should prevail.

Recognising this fundamental point of law and the need for uniform application, the Technical Board of Appeal (T 439/22) referred several questions to the EBA. The most pertinent questions, which G 1/24 specifically addressed, were:

• "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?"
• "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?" (The EBA ultimately considered this question subsumed by the answer to the previous one).

The EBA accepted the referral, acknowledging the need for clarity and, significantly, the desire to harmonise EPO practice with the burgeoning UPC. The EBA explicitly referred to UPC case law (such as NanoString Technologies -v- 10x Genomics) which consistently applies a holistic approach to claim interpretation.

Key Takeaways from G 1/24

The EBA's decision can be distilled into two crucial points:

1. Claims remain the starting point: The EBA reaffirmed that the claims continue to be the primary basis for assessing the patentability of an invention under Articles 52 to 57 EPC. This upholds the fundamental principle that the claims define the scope of protection sought.
2. Description and drawings always consulted: Crucially, the EBA ruled that the description and drawings shall always be consulted to interpret the claims when assessing patentability. This is a significant departure from previous, sometimes divergent, EPO practice where the description and drawings were only consulted if the claims, when read in isolation, were considered unclear or ambiguous. This "classical approach" is now explicitly rejected.

In essence, G 1/24 arose from a very practical dispute about the scope of a claim term, which exposed a deep-seated ambiguity in EPO practice and highlighted the disconnect with national court approaches. The EBA's decision provides the much-needed authoritative guidance, steering EPO practice towards a more integrated and consistent framework for claim interpretation across Europe.

Five Practical Tips for Drafting and Prosecuting Patent Applications in Europe

The G 1/24 decision necessitates a careful review of patent drafting and prosecution practices. Here are five practical tips for applicants and their patent attorneys:

1. Ensure Consistent Terminology: More than ever, ensure that the terminology used in the claims is consistent with, and clearly defined by, the description. Avoid using terms in the claims that have a different meaning in the description, or broad terms in the claims that are only described narrowly in the examples. Any specific definitions or interpretations of terms should be clearly and explicitly stated in the description, linking them directly to the claim language.
2. Scrutinise "Broadening" Descriptions: Be particularly mindful of overly broad statements or definitions in the description that could inadvertently expand the interpretation of a claim beyond what was intended, especially if that broader interpretation could lead to novelty or inventive step issues. While it's still beneficial to provide a broad context for the invention, consider whether certain statements could be misconstrued to cover prior art if "read into" the claims.
3. Align Examples with Claims: While always good practice, it's now even more vital that the examples and embodiments presented in the description clearly support and illustrate the claimed invention. If a claim feature is described in a very specific way in all examples throughout the full description, it might be interpreted narrowly, even if the claim language itself is broader.
4. Proactive Description Amendments: Expect EPO examiners to pay even closer attention to the consistency between claims and description. Be prepared to proactively amend the description during prosecution to ensure it aligns perfectly with the allowed claims. This may involve removing or disclaiming subject matter that falls outside the scope of the claims, even if not strictly required by clarity objections. The EPO's emphasis on coherence between claims and description is now heightened. Be mindful, however, that amendment of the description might lead to an added matter problem if the amended description would change the meaning of terms in the claims.
5. Consider Fallback Positions: Continue to provide several fallback positions, considering not just the words of the claims, but the definitions too. Where tempted to use a term having a specific meaning in a given field, consider introducing a further term intended to have that specific same meaning, and provide the definition for that further term.

G 1/24: Good for Applicants?

There are several reasons why this decision can be considered beneficial for patent applicants:

• Increased Legal Certainty and Consistency: The most significant advantage is the alignment of EPO examination practice with national court and UPC interpretation. This should lead to greater legal certainty for patentees, as the scope of their granted patents is less likely to be interpreted differently in pre-grant and post-grant proceedings. This consistency reduces the risk of "ambush" scenarios where a patent's scope is narrowed post-grant due to an interpretation not applied during examination.
• More Realistic Claim Interpretation: By mandating that the description and drawings always be consulted, the EPO is moving towards a more holistic and realistic interpretation of claims. It acknowledges that the skilled person would naturally refer to the entire patent specification to understand the invention, rather than relying solely on the claim language in isolation. This can help prevent overly literal interpretations that might miss the true essence of the invention.

G 1/24: Bad for Applicants?

The decision also presents some potential challenges for applicants:

• Heightened Scrutiny of Description: The other side to the "always consulted" rule is that any inconsistencies or overly broad statements in the description that were previously overlooked (under the "claims are clear in isolation" principle) could now lead to more objections during examination or become grounds for invalidity in opposition or revocation proceedings. This requires meticulous drafting of the entire application, and also meticulous prosecution in Europe to avoid added matter.
• Increased Workload for Drafting and Prosecution: Ensuring perfect alignment and avoiding unintended interpretations across the claims, description, and drawings will likely demand more time and effort during the drafting phase. Similarly, prosecution at the EPO may become more involved, with more back-and-forth regarding the relationship between the claims and the rest of the application. Accordingly, it may be that this increases costs for some applicants where claim scopes need to be amended during prosecution.
• Potential for Narrower Interpretation (in some cases): While the aim is consistency, for applications that relied heavily on a deliberately broad claim wording with minimal detailed support in the description, examiners might now be more inclined to read features from the description into the claims, potentially narrowing their scope if the broader interpretation is not sufficiently supported by the overall disclosure. This reinforces the need for robust disclosure that fully supports the claimed invention.

In conclusion, G 1/24 marks a significant step forward in European patent law, promoting greater coherence and predictability. For European patent attorneys, it's a clear signal to refine our drafting and prosecution strategies, ensuring that the entire patent specification presents a unified and robust picture of the invention we seek to protect.

This article was prepared by Director, Chris Cottingham. Please contact us if you want to discuss how any of the issues raised might affect your own European patent applications.