The appeal lodged by the opponent (appellant) lies from the opposition division's decision to reject the opposition against European patent No. 2 691 417. The patent is entitled "Antibody Fc variants".
Claim 1 of the patent reads:
"1. An antibody or an Fc fusion protein comprising an Fc variant of a wild-type human IgG1 Fc region, wherein the Fc variant of the wild-type human IgG1 Fc region contains amino acid substitutions P329G, L234A and L235A, wherein the residues are numbered according to the EU index of Kabat."
The board considers that claims 4 and 5 of main request and of auxiliary requests 1-5 add subject-matter.
The set of claims in auxiliary request 6, filed by letter of 21 February 2022, i.e. after the notification of the summons to oral proceedings, differs from the main request in that dependent claims 4 and 5 have been deleted and claims 6 to 8 renumbered accordingly.
Article 13(2) RPBA 2020, which relates to the situation "after notification of a summons to oral proceedings", thus applies.
In a first step it needs to be assessed whether filing auxiliary request 6 amounts to an "amendment of the party's appeal case" within the meaning of Article 13(2) RPBA 2020.
A number of decisions have held that deleting a dependent claim that does not represent an amendment to the factual and legal framework of the case is not an amendment within the meaning of Article 13(2) RPBA 2020.
In this board's view, however, a party's case should not be confused with the subject-matter that is presented for consideration of patentability. On the contrary, a new claim request normally represents a new line of defence against the opposition, and by adding this new line of defence to its case the respondent has undoubtedly changed its case.
A new request filed afterwards with a set of claims that is different to that of the previous requests, is usually to be regarded as an 'amendment to a party's appeal case' within the meaning of Article 13 RPBA 2020.
In a second step, it has to be established whether there are "exceptional circumstances, which have been justified by cogent reasons", which allow the request to be admitted into the appeal proceedings.
The respondent argued that neither the opposition division's preliminary opinion nor the decision under appeal had addressed the question of added subject-matter with regard to claims 4 and 5. Before receiving the board's communication under Article 15(1) RPBA 2020, the respondent could therefore not have reasonably expected it to become relevant in the appeal proceedings. The deletion did not change the assessment of any other issue of the appeal.
The board concluded that although the deletion of dependent claims 4 and 5 constitutes an amendment to the appeal within the meaning of Article 13(2) RPBA 2020, it did not change the factual and legal framework of the appeal. The appellant was therefore not disadvantaged by the admittance of the request.
The board concludes that deleting dependent claims 4 and 5 enhances procedural economy as doing so clearly overcomes existing objections without giving rise to any new issues. In the board's opinion these are cogent reasons justifying exceptional circumstances as per Article 13(2) RPBA 2020.
Auxiliary request 6 was admitted into the appeal proceedings.
Claim 5 is formulated in the form of a first medical use ("The antibody or Fc fusion protein according to any one of claims 1-4 for use as a medicament") according to Article 54(4) EPC. It is to be analyzed whether the compounds are suitable for use as a medicament.
The patent shows that the PGLALA mutations can be introduced into known therapeutic antibodies having a human IgG1 Fc region and that an antibody of this kind provides relevant medical effects such as reduced Fc receptor affinity and reduced effector function, known to be useful in several therapeutic contexts. It is plausible that this finding also extends to Fc fusion proteins in which the Fc part is fused to a therapeutically effective protein and that the mutated antibodies or Fc fusion proteins can be used as a medicament in said known therapies without the mutations in the Fc region impairing the therapeutic effect.
Therefore, the only remaining question is whether claim 5 should be restricted to these particular therapies.
This board cannot derive any requirement from the EPC whereby a patent would have to show that a compound is suitable for each and every disease in order for a first medical use to be sufficiently disclosed. Instead, it is sufficient to show that the compound is suitable for at least one particular medical use, as is the case in the patent at issue.
Thus, the invention to which the claims relate is sufficiently disclosed in the patent.
The case is remitted to the opposition division with the order to maintain the patent on the basis of claims 1 to 6 of auxiliary request 6.