T 2522/10 - Switching from novelty-destroying to CPA

EPO T 2522/10

For the decision, click here

Key point

• In this case, after the Board had held the claims to be novel over D20 during oral proceedings, the applicant wished to argue lack of inventive step using D20 as closest prior art, while only D6 and/or D7 were relied on as closest prior art in the written submissions. Is the attack based on D20 to be refused under Art. 13 RPBA?
• The present Board does not admit the new inventive step attack based on D20, noting that it had expressed in its preliminary opinion that D20 did not anticipate the claims. However, also the Board also remarks that D20 has a different purpose and hence does not qualify as closest prior art.

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Amendment to the respondent's case (Article 13 RPBA)

37. During the written part of the appeal proceedings the respondent had submitted that either document D6 or document D7 represented the closest prior art. In the course of the oral proceedings before the board the respondent proposed document D20 as closest prior art. This represented an amendment to the respondent's case. Pursuant to Article 13 RPBA any amendment to a party's case after it has filed its grounds of appeal or reply may be admitted and considered at the board's discretion.

38. The respondent had justified the amendment of its case at this late stage of the appeal proceedings by saying that it was only in the course of the discussion of document D6 during the oral proceedings that it had understood that the board did not consider document D20 as novelty destroying.

39. However, the board had indicated in its communication sent under Article 15(1) RPBA that is considered, albeit provisionally, that the opposition division had correctly decided that document D20 did not anticipate the claimed subject-matter. Accordingly, the respondent was aware of the board's opinion on document D20 well before the date of the oral proceedings.

40. Document D20 is concerned with the processing of C-terminal lysine and arginine residues of proteins isolated from mammalian cell culture. It discloses that C-terminal Lys residues are often absent in proteins isolated from mammalian cell culture and that incomplete removal of C-terminal Lys residues causes charge heterogeneity. Such charge variants can be resolved by cation-exchange chromatography. RhuMAb HER2, for example, shows five charge species (see Figure 2) in cation-exchange chromatography. The acidic peaks 1 and 2 are deamidated at Asn30 in one light chain, peak 1 has no Lys450 residues, while peak 2 has one Lys450 residue. Although document D20 thus mentions deamidation of rhuMAb HER2, it is concerned with the identification of variants after the production of the antibody in culture and not with its purification. Thus it relates to a different purpose and does not qualify as the closest prior art.

41. The board concluded from the above that the amendment to the respondent's case was not only late but that also document D20 did not in fact qualify as closest prior art. For these reasons the board decided, in the exercise of its discretion pursuant to Article 13 RPBA, not to admit the amendment of the respondent's case in the appeal proceedings.