Legal Evaluation of Each Statement
Opposition proceedings are pending against all claims of EP-B. The only ground invoked by the opponent is Art. 100(c) EPC (added subject-matter). On 29 September 2025, the EPO receives third-party observations alleging:
- lack of novelty of claim 1 over D1; and
- insufficient disclosure.
Third-party observations are governed by Article 115 EPC and Rule 114 EPC. The person making them does not become a party to the opposition.
Legal Evaluation of Each Statement
a) “Since third party observations can only be filed concerning issues arising under Articles 52 to 57 EPC, the opposition division will not consider the reasoning concerning lack of sufficiency of disclosure.” — False
This statement is wrong on its premise: third-party observations are not confined to Arts. 52–57 EPC.
The EPO Guidelines explain that Art. 115 observations, while often about novelty/inventive step, may also be directed to sufficiency of disclosure (Art. 83) and even to unallowable amendments and other substantive issues.
Therefore, the opposition division may take note of and consider the third party’s Art. 83 reasoning (subject to procedural discretion on relevance and timing, but not excluded merely because it is Art. 83).
b) “The submissions of the third party will be forwarded by the EPO to the patent proprietor.” — True
Rule 114(2) EPC explicitly requires that third-party observations shall be communicated to the applicant or proprietor, who may comment on them.
So the EPO will forward/communicate them to the proprietor (and typically also make them available in the file).
c) “The submissions of the third party will be accessible to the public through file inspection.” —True
Under Article 128 EPC, the files of a European patent application/patent are generally open to inspection after publication, subject to limited exceptions.
The Guidelines confirm specifically that Art. 115 observations are an integral part of the file and thus open to inspection in accordance with Art. 128.
Hence, the submissions will be publicly accessible via file inspection.
d) “The opposition division is allowed to introduce into the proceedings lack of novelty with respect to claim 1 as a fresh ground for opposition.” - True
Even though the opponent relied only on Art. 100(c) EPC, the opposition division has the power under Article 114(1) EPC to examine the facts of its own motion and may, in first-instance opposition proceedings, raise a new ground for opposition (e.g. Art. 100(a) EPC: lack of novelty) if it appears prima facie relevant to the maintenance of the patent.
The case law framework (discussed in the EPO Case Law book) recognises the department’s ability to raise fresh grounds ex officio in opposition and stresses parties must have an opportunity to comment.
Be careful not to confuse this with the appeal stage: on appeal, a fresh ground may generally be considered only with the proprietor’s consent (G 9/91 / G 10/91 line).
But in opposition at first instance, introducing novelty as a fresh ground is allowed under Art. 114(1) EPC (with due process).
Exam Tip:
- Art. 115 / Rule 114 EPC: third-party observations can address more than Arts 52–57 (notably Art. 83 and unallowable amendments).
- Communication + publicity: observations are communicated to the proprietor (Rule 114(2)) and are open to file inspection (Art. 128; Guidelines A-XI).
- Fresh grounds: distinguish opposition (OD may raise new grounds ex officio) from appeal (fresh grounds generally need proprietor consent).
Legal Disclaimer
The information provided in this post is for general informational purposes only and does not constitute legal advice. This content should not be used as a substitute for professional legal advice tailored to your specific circumstances. For advice related to any specific legal matters, you should consult a qualified attorney.