Enlarged Board of Appeal Decision G 1/24 (18 June 2025): EPO’s new ruling on claim interpretation
The long-awaited Enlarged Board of Appeal (EBoA) decision G1/24 provides significant endorsement of the EPO’s principles on claim construction, especially with regard to the assessment of patentability. This landmark decision calls for harmonization of claim interpretation principles between the EPO, the national courts as well as the UPC. This case, upon referral from T 439/22, essentially concerned the question whether the description can be relied upon for interpretation to apply a broader scope of claims, even when the claim language is unambiguous and, without further context, has a narrower meaning.
“The claims are the starting point and the basis for assessing the patentability of an invention under Articles 52 to 57 EPC. The description and drawings shall always be consulted to interpret the claims when assessing the patentability of an invention under Articles 52 to 57 EPC, and not only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation.” (emphasis added)
To sum up, G1/24 provides a holistic interpretation approach (“patent as a whole”) starting from the claims based on Article 69 EPC and Article 1 of the Protocol on the Interpretation of Article 69 EPC. In its decision, the EBoA clearly emphasizes the relevance of the patent description as a constant interpretative tool, the examples helping in understanding the features in the claim.
UPC Court of Appeal 26 February 2024, 10x Genomics v. NanoString, UPC_CoA_335/2023
10x Genomics applied for a preliminary injunction against Nanostring based on EP 4 108 782, a patent claiming a multiplex method for detecting analytes in cell or tissue samples. The UPC Court of First Instance (LD Munich) had previously granted that injunction. That decision was overturned by the UPC Court of Appeal (Luxembourg) on 26 February 2024: it denied 10x Genomics' PI on appeal.
The CoA set out ground rules for claim interpretation. Referring to Article 69 EPC, the CoA set out that patent claims must be interpreted from the skilled person's point of view. The patent's claims are "not only the starting point, but the decisive basis for determining the protective scope of a European patent". The patent's description and the drawings must always be used as explanatory aids. That does not mean the patent claims merely serve as a guideline. These principles apply to both validity and infringement.
UPC Court of Appeal 30 April 2025, Insulet v. EOFlow, UPC_CoA_768/2024
Insulet applied for preliminary measures against EOFlow based on EP 4 201 327, a patent claiming a fluid delivery device for delivering therapeutic liquids to a patient, and more particularly, to an infusion pump for delivering therapeutic liquids to a patient. The UPC Court of First Instance (CD Milan) refused Insulet’s request. On 30 April 2025, however, the UPC Court of Appeal (Luxembourg) overturned that decision and granted the requested preliminary measures. While the Court of First Instance had considered it more likely than not that the patent lacked novelty, the Court of Appeal reached the opposite conclusion on the basis of a different claim construction.
Taking the opportunity to clarify general principles, the CoA emphasized that the technical meaning of the features of the claims must be interpreted from the point of view of the person skilled in the art. This is a notional entity that cannot be equated with any real person in the technical field of the invention, including a party expert.
In addition, the CoA clarifies the role of party experts in claim construction. Interpretation of patent claims is a matter of law. The CoA cannot leave the judicial task of interpreting the patent claim to an expert but has to construe the claim independently. Expert opinions will be considered in circumstances concerning facts that can be proven, but only with respect to those facts.
As a consequence, the skilled person cannot simply be equated with a party expert, nor can the CoA adopt an expert’s construction without scrutiny.
In the present case, the CoA expressly distanced itself from the construction of EOFlow’s expert, which had been followed by the Court of First Instance. By independently construing the claims, the CoA arrived at a different interpretation, which in turn altered the novelty assessment and ultimately led to the grant of preliminary measures.
Court of Appeal, 25 November 2025, Meril v Edwards, UPC_CoA_21/2025
In Meril v Edwards, the CoA further developed the approach to claim construction first outlined in 10x Genomics v NanoString, focusing on the relationship between claim language and disclosed embodiments.
The patent in suit, EP 3 646 825, concerned a prosthetic heart valve with a frame made entirely of hexagonal cells. Meril’s product used irregularly shaped side struts forming elliptical openings between neighboring hexagonal cells. This “honeycomb” structure improves the transport of the valve through the vein while maintaining the stability of the structure.
The CoA confirmed that claim interpretation must not be reduced to a specific embodiment. As the patent in suit did not prescribe a specific strut shape, infringement was found.
Additionally, EP 3 646 825 disclosed embodiments of the invention that clearly did not comprise parallel side struts. Accordingly, the frame in the disclosed embodiment did not form hexagonal cells but rather “rhomboid” cells which were known in the prior art.
The CoA confirmed that, as a general rule, embodiments presented as part of the invention should fall within the scope of the claims.
However, this does not apply if the patent as a whole clearly teaches the person skilled in the art that the disclosed embodiment is not claimed, e.g. the technical specification is not addressed by the teachings of the patent claim.
In this case, the patent explicitly differentiated between “hexagonal” and “rhomboid” cells. Claim 1 addressed only hexagonal structures. The rhomboid embodiment was therefore not covered by the claim. The CoA then found that the teaching of claim 1 does not encompass “rhomboid” structures.
Court of Appeal, 20 Dec 2024, Alexion v Amgen, UPC_CoA_405/2024
Alexion v Amgen shows the interplay between claim construction and patent validity (specifically, sufficiency), with a strict CoA on whether errors in claims can be corrected via interpretation.
Alexion sought a preliminary injunction based on EP 3 167 888, claiming i.a.“[a] pharmaceutical composition comprising [an antibody that binds C5 comprising a heavy chain consisting of SEQ ID NO:2 and a light chain consisting of SEQ ID NO:4]” (claim 2). The target was Amgen’s eculizumab biosimilar.
The patent description discloses the light chain sequence as including 22 additional amino acids that are not present in eculizumab. The skilled person would arguably recognize these as a signal peptide, cleaved off during production.
The question was whether the claimed antibody should be interpreted as covering the light chain sequence without this signal peptide.
In grant proceedings (T 1515/20), the Technical Board of Appeal of the EPO (“TBA”) rejected the amendment to expressly exclude the signal peptide from the claim, reasoning that the error was not obvious enough to be corrected under Rule 139 EPC.
The Hamburg Local Division nevertheless interpreted the claims as covering a light chain sequence without signal peptide, as the skilled person would recognize the signal peptide and its necessary removal for a functional antibody. The CoA disagreed with this claim interpretation, stating that an error in a claim “can only be corrected by way of interpretation of the patent claim if the existence of an error and the precise way to correct it are sufficiently certain to the average skilled person on the basis of the patent claim, taking into account the description and the drawings and using common general knowledge.”(§35, emphasis added). The Court recognized this as a strict standard, for legal certainty.
The Court found in casu that:
the error (implied inclusion of the signal peptide) was not sufficiently certain;
nothing in the patent specification pointed to the signal peptide’s exclusion;
a signal peptide could be considered an (unusual) part of the antibody; and
the skilled person would not rule out that the antibody could be functional with signal peptide, particularly as this was Alexion’s own assertion, that was endorsed by the TBA, during grant proceedings (indicative of how the skilled person would have viewed the claims).
The CoA concluded that the claims must be interpreted as covering a light chain sequence with signal peptide. As such an antibody would not be functional (which Alexion had meanwhile admitted), the CoA found it more likely than not that the subject matter of claim 2 is insufficiently disclosed, dismissing the PI.
UPC sets out a new harmonized legal standard for claim construction for the assessment of validity and infringement
In summary, the above discussed UPC case law shows that the CoA applies the ruling set out in the hallmark decision 10x Genomics v. NanoString, which may be considered the UPC’s gold standard for claim interpretation. Claim construction is based on Art. 69 EPC and its protocol and in view of the person skilled in the art. The key message is that a patent claim shall not merely serve as a guideline, rather 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 unclarities or ambiguities in the patent claim. Interestingly, EboA Decision G1/24 explicitly referred to the UPC case law 10x Genomics v. NanoString and adopted the legal principles on claim construction therein emphasizing the need for consistent interpretation of Article 69 EPC and harmonization across jurisdictions.
Article by Tung-Gia Du, Dirk Henderickx, Ine Letten, Alexander Crames and Anna Cooreman