EPO: T 0977/25 Ambiguity Added Subject-Matter in E-Cigarette Patent

• The EPO Board of Appeal in T 0977/25 found an ambiguous word in an amended method claim for an e-cigarette cartridge.
• The pronoun "it" was deemed ambiguous, leading to a finding of added subject-matter.
• This occurred because both possible interpretations of the ambiguity introduced new subject matter not present in the original filing.
• The decision underscores the strict scrutiny of claim language and amendments at the EPO, aligning with principles from G1/24 and G1/25.
• The ruling highlights the critical need for precise claim drafting to avoid added subject-matter objections.

The Board's determination was that the word "it" within the amended claim was open to multiple interpretations.

The European Patent Office (EPO) Board of Appeal, in its decision T 0977/25, recently highlighted the critical importance of linguistic precision in patent claims, particularly following amendments. The case centered on an amended method claim pertaining to an e-cigarette cartridge, where the Board identified a specific ambiguity concerning the pronoun "it". This seemingly minor linguistic imprecision ultimately led to a significant finding of added subject-matter.

The Board's determination was that the word "it" within the amended claim was open to multiple interpretations. Crucially, the ruling established that irrespective of which interpretation was adopted, the amended claims introduced subject matter that extended beyond the content of the application as originally filed. This outcome underscores the rigorous scrutiny applied to claim language during the patent prosecution process, especially when modifications are made.

The finding in T 0977/25 resonates with the broader jurisprudential landscape at the EPO, particularly in light of recent Enlarged Board of Appeal decisions G1/24 and G1/25. These landmark rulings have reinforced the strict requirements for consistency between claims and the description, and the prohibition against introducing new subject matter through amendments. While T 0977/25 specifically addresses an `EPO T 0977/25 claim ambiguity` leading to added subject-matter, its implications align with the heightened focus on ensuring that all claim amendments are unequivocally supported by the original disclosure.

Under EPO practice, `patent added subject-matter G1/24 G1/25` principles dictate that any amendment must not extend the scope of protection or introduce information not derivable from the application as filed. The `Board of Appeal ambiguity interpretation` in T 0977/25 demonstrates that even an `unresolved ambiguity` can trigger an added subject-matter objection if its potential meanings are not fully supported by the initial disclosure. This reinforces the need for absolute clarity in claim drafting to avoid any interpretation that could introduce new technical information.

The decision in T 0977/25 serves as a stark reminder for patent applicants and their legal representatives regarding the paramount importance of `EU patent claim drafting precision`. Even a single ambiguous word, such as the pronoun "it" in the `e-cigarette cartridge patent claims`, can lead to an `added subject-matter` objection and potentially jeopardize the validity of a patent application. This is particularly pertinent during the amendment phase of prosecution, where changes intended to clarify or narrow claims can inadvertently introduce new issues.

Patent attorneys must exercise extreme diligence to ensure that all claim language is unambiguous and fully supported by the original application. The `T 0977/25 ambiguity added subject-matter` ruling emphasizes that the EPO will not tolerate linguistic imprecision that allows for interpretations extending beyond the initial disclosure. This necessitates meticulous review of every word in a claim, especially when responding to office actions or making voluntary amendments, to prevent any unintended broadening or introduction of new technical content.

Patent attorneys must ensure absolute clarity in claim drafting and amendments, as even minor ambiguities can lead to added subject-matter objections and potential invalidation, especially in light of recent EPO jurisprudence. This affects how they advise clients on patent prosecution and litigation risk.

Source: Original reporting via {source}