In this examination appeal case Board 3.3.04 had to deal with a request for correction.
Claim 1 of the application as filed read:
1. An isolated variant hepatitis B surface antigen comprising an amino acid sequence wherein mutations from hepatitis B wild type ayw2 strain appear as follows: at position 103 isoleucine is present instead of methionine, at position 118 lysine is present instead of threonine, at position 120 glutamine is present instead of proline, at position 170 serine is present instead of leucine, and at position 213 serine is present instead of leucine. (my emphasis)
In the request refused by the Examining Division (ED), “170” had been amended to read “175”.
The ED found this claim to violate A 123(2), and the Board confirmed its analysis:
 The statement of the grounds of appeal is identical to the submissions of 17 March 2005 before the ED. Accordingly, the statement of grounds includes a section entitled “Correction of obvious errors (R 139)”. The board therefore considers that the amendment to claim 1 under consideration entails a request for correction of an obvious error in the present appeal procedure also.
 R 139 (former R 88 EPC 1973) provides in its second sentence that a correction of errors in documents filed with the EPO which concerns the description, claims or drawings can only be allowed if the correction is obvious in the sense that it is immediately evident that nothing else would have been intended than what is offered as correction. In its opinion G 3/89 , the Enlarged Board of Appeal (EBA) considered that, for a correction under R 88, second sentence EPC 1973, that concerns the disclosure of a European application or a European patent to be allowed, the respective parts of the disclosure for which a correction is requested must, either on the date of filing or following an amendment under A 123 EPC 1973 (unchanged as to substance in EPC 2000), contain such an obvious error that a skilled person would be in no doubt that the information concerned could not be meant to read as such. Furthermore, the skilled person must be in a position objectively and unambiguously to recognise the incorrect information using common general knowledge. If, on the other hand, it is doubtful whether that information is incorrectly defined, then a correction is ruled out (points  and  of the reasons).
 The opinion G 3/89 of the EBA, supra, held furthermore that any correction under R 88 EPC 1973 (corresponding to R 139) is of a strict declaratory nature and thus has not to infringe the prohibition of extension of subject-matter under A 123(2) (see Headnote 2). Accordingly the decision of the ED in the present case also had the effect of refusing the correction under R 139 as referred to in the statement of the grounds for appeal.
 The amendment/correction under consideration is the change of the wording “at position 170 serine is present instead of leucine” in claim 1 to the wording “at position 175 serine is present instead of leucine” (and a corresponding change on page 8, in line 17, of the application as filed; emphasis added by the board).
 In its decision, the ED acknowledged that it was evident to a skilled person that an error existed. However, the amendment/correction as now contained in claim 1 was not the only possible correction as a person skilled in the art would have to decide between the correction of “170 L (TTA) –> S (TCA)” to “175 L (TTA) –> S (TCA)” or to “170 F (TTC) –> S (TCA)”, i.e. between a correction of the position of the mutation or the correction of the amino acid at position 170 and of the corresponding codon. It found that it was therefore not immediately evident what the correction should be and refused the correction pursuant to A 139.
 As can be taken from opinion G 3/89 of the EBA, supra, the conditions an error has to fulfil to benefit from a correction are that it must be obvious that an error has occurred and it must be immediately evident what the correction should be.
 The board considers that it may have been obvious to the person skilled in the art that an error occurred when consulting the sequence of ayw2 which was known from GenBank Accession No. X02496 and wherein the amino acid residue 170 is phenylalanine (F), encoded by the codon TTC. The first condition may therefore be fulfilled.
 However, the board considers that the second condition is not fulfilled because, as demonstrated by the ED in its decision (see point , above), more than one possible correction becomes immediately evident to the skilled person when considering the error.
 The appellant has submitted in essence two lines of argument in favour of the position that the proposed amendment/correction was the only correction which was immediately evident.
[9.1] A first line of argument was that the second possible correction/amendment referred to in point , above, wherein both the amino acid residue and the codon encoding had to be altered, was far less likely to occur in nature as a single mutation underlying the correction/amendment under consideration as it required the substitution of two consecutive bases rather than the substitution of a single base. The other four amino acid changes between LBN and the known ayw2 subtype referred to in claim 1 were also the result of a single base substitution. This second possible correction would therefore not result from a mind willing to understand as it was not “technically sensible” (see decision T 190/99).
[9.2] A second line of argument was that there were only three leucine (L) residues encoded by a TTA codon between positions 32 and 226 of the amino acid sequence of the prior art isolate ayw2, i.e. at positions 175, 213 and 216. Since the five amino acid mutations in the new LBN strain were listed in a numerical order (see page 8, lines 14-20 of the aplication as filed), the correct residue number for the leucine (L) encoded by TTA between residue 120 and residue 213 could therefore clearly only be 175. That the reference to Leucine (L) was intentional by the drafter of the application was clear to a skilled person seeing that claim 1 as originally filed also referred, as did the passage on page 8 of the application as filed, to Leucine.
[9.3] The board cannot accept either of these lines of argument.
Indeed, it is first noted that the appellant has not denied that the second possible correction/amendment referred to by the ED would not be considered by the skilled person, but has rather argued that it would be based on a mutation which would be “less likely to occur in nature”. Furthermore and secondly, the appellant has not argued that when reading the application as filed, the skilled person would have received the technical information that the five amino acid differences were due to point mutations. The board therefore concludes that, because a double mutation would not be precluded for a skilled person addressing the error, the same skilled person would take both possible corrections/amendments into consideration without thereby frustrating the principles established in decision T 190/99 that when considering a claim the skilled person should rule out interpretations which are illogical or which do not make technical sense and a patent should be construed by a mind willing to understand, not a mind desirous of misunderstanding.
 In view of the above considerations, the board considers that the correction of the error in claim 1 as originally filed was not immediately evident to a person skilled in the art. Thus, the correction proposed by the appellant, and set out in the claims, does not meet the requirements of R 139.
 The decision of the ED is therefore correct in the point under appeal. […]
The appeal is dismissed.
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