The EPO Enlarged Board of Appeal (EBA) has issued its much-anticipated decision in G1/24, confirming a foundational principle of European patent law: the claims must always be interpreted in light of the description and drawings. The decision definitively sets aside a divergent line of case law which held that the description should only be consulted when the claims are ambiguous.
While G1/24 provides welcome clarity on the correct approach, it opens up a practical question for patent attorneys and their clients: who stands to benefit more from this harmonised standard? Is this a win for patentees, for opponents, or a balanced shift in the equilibrium?
Though it is early days, the referring decision, T 0439/22, provides a blueprint for how the principles affirmed in G1/24 may be applied. The Board in T 0439/22, after a comprehensive review of over 40 years of Board of Appeal case law, national court decisions, and the recent UPC decision in Nanostring, developed a set of principles to reconcile the case law. If these principles are adopted by Opposition Divisions and Boards of Appeal, the post-G1/24 landscape may be significantly more favourable to opponents.
Claim interpretation score card: the principles in T 0439/22
The reasoning in T 0439/22 suggests a clear tilt in favour of third parties by placing a heavy burden of clarity on the patentee. Let's examine the key principles.
1. Broad Principle & Legal Certainty (Opponents 1-0)
The Board stressed that for reasons of legal certainty, the primary source for understanding the claimed invention is the claim itself. In reason 6.2.1, the Board stated:
"[I]t is in the interest of legal certainty that the alternative meaning of [a] term be made apparent in the context of the claim itself. [...] If patent proprietors are not willing to embed that alternative meaning directly in the wording of the claim although they could, they should not profit from alternative understandings based only on information in the description or the drawings."
This principle discourages patentees from relying on the description to retroactively assign a non-standard meaning to a claim term, demanding that such intentions be clear from the outset in the claims.
2. Narrowing Information in the Description (Opponents 2-0)
When the description provides a narrower, alternative meaning to a term used in a claim, the Board favoured a broad construction for patentability purposes. According to reason 6.2.3:
"[C]onstrue the patent when in doubt in a way that the term used in the claim is understood in a broad sense, such as to include both potential meanings [(with and without reference to the description)]. Thus, where the information giving the terms in the claims the meaning as intended in the patent is not included in the claims even though it could have been by amendment of the claims, the share of prior art examined that is potentially novelty-destroying or could render an invention obvious is increased during examination and opposition proceedings."
This approach expands the scope of the claim for the assessment of patentability, thereby increasing the universe of potentially relevant prior art an opponent can cite.
3. Broadening Information in the Description (Opponents 3-0)
The Board also considered the inverse scenario. While it noted that narrowing definitions in the description may not be enough to override a term's plain meaning, it gave more weight to broadening definitions. From reason 6.3.1:
"Definitions or similar information narrowing the meaning of a term will, when only contained in the description, often not suffice to totally override the ordinary meaning of the term used in the claim. On the other hand, broadening definitions and the like in the description may be a clear signal that the term used in the claim may not only be understood in the conventional way but also in the broader sense set out in the description."
This again points towards a default preference for a broader claim construction, which typically benefits the party challenging the patent's validity.
4. Any technically reasonable understanding (Opponents 4-0)
Finally, the Board placed the onus squarely on the patentee to ensure consistency and clarity between the claims and the description. As per reason 6.3.2:
"[I]t would be up to the patent proprietor to correlate the wording of the claims and the content of the description to make it clear what invention is actually claimed. Where this is not done[...] any understanding of the claim wording which is technically reasonable should not normally be excluded by the claim"
A failure to harmonise the claims and description therefore opens the door for any technically reasonable interpretation to be used against the patentee.
A Crucial Lifeline for Patentees
While the principles above point to a 4-0 lead for opponents, the core holding of G1/24 provides a critical point for patentees. The mandatory requirement to always consult the description acts as a potential safeguard against revocation due to minor, inadvertent drafting errors in the claims.
Cases where patents were revoked over grammatical oversights or similar errors, highlight the dangers of a purely literal interpretation of the claims in isolation. By requiring a holistic reading of the patent document, G1/24 should make such outcomes less likely. Where the description and drawings make the patentee’s true intention clear, a simple slip of the pen in a claim should not be fatal. This should ensure the focus remains on the substance of the invention, not on "gotcha" linguistics.
Final Score & The Path Forward
The final scorecard appears to be Opponents 4 - 1 Patentees. If the principles outlined in T 0439/22 become the standard for applying G1/24, we can expect a future where the bar for clarity and precision in patent drafting is set even higher, creating a more challenging environment for patentees during opposition. However, the decision also injects a degree of fairness into the system, reducing the likelihood that valuable patent rights are lost over trivial mistakes.
It remains to be seen how this will play out in practice. For now, the message is clear: draft with precision and ensure the entire specification tells a single, coherent story. We expect more disputes to turn on this issue, so further guidance from the Boards of Appeal will surely come forth soon.
If you would like to discuss how this could impact your cases or how to adapt your strategies, do reach out to Alexander Korenberg or your usual contact at Kilburn & Strode.