The opponent filed an appeal after the Opposition Division had maintained the patent in amended form.
Claim 1 of the main request before the Board read (in English translation; amendments with respect to claim 1 as granted are underlined)
1. A method for preparing a factor VIII solution which is virally secure, according to which:
- a solution that has been previously purified, containing factor VIII-von Willebrand factor (factor VIII-vWF) protein complexes, is prepared;
- a step allowing to dissociate the high molecular weight factor VIII-vWF complexes by means of a chaotropic ion present in sufficient amount to enable the dissociation, as well as to obtain a solution that is essentially devoid of factor VIII associated with vWF of high molecular weight, is carried out;
- a step of filtration of said solution through a hydrophilic filter having a porosity of 15 nm at most is carried out.
Claim 1 as filed had contained the feature that the solution contained factor VIII “of high or very high purity”, but the IPEA had raised a clarity objection, which had led the applicant to delete this feature.
In what follows, the Board examines the above claim as to its compliance with A 123:
*** Translation of the French original ***
 The question arises whether the skilled person would have deduced the claimed process having the feature “a solution that has been previously purified, containing factor VIII-vWF protein complexes is prepared” from the original patent application.
 The [patent proprietor] considers that the skilled person would understand that the expressions “previously purified” and “of high or very high purity” are synonyms in the context of the description. The [patent proprietor] pointed out that in this context, according to A 69(1), the claims have to be interpreted taking into account the description, and that the skilled person would interpret claim 1 such that the feature “a solution that has been previously purified is prepared” in claim 1 would incite him to prepare a starting solution having “high or very high purity”.
 According to the Board, the skilled person would only understand from the context of claim 1 and its feature according to which “a solution that has been previously purified is prepared” that a purification has to take place beforehand and that it has to be such that the other method steps can be performed in a technically reasonable way. However, the skilled person would not implicitly understand that this can only be done if the starting solution is purified such that it has a degree of purity that can be qualified as “high or very high”. In other words, in the context of claim 1, the skilled person would not implicitly establish a link between the expressions “previously purified” and “of high or very high purity”.
 The Board is not persuaded by the argument of the [patent proprietor] according to which a limitative interpretation of the expression “previously purified” follows from the interpretation of claim 1 under A 69(1).
 A 69(1) governs the interpretation of claims when it comes to determining the scope of protection, and, as a consequence, it is questionable whether this article can be used for interpreting claims when the allowability of amendments is examined (see Case Law, 6th edition, 2010, II.B.5.3.1, first paragraph).
 However, if the reasoning of the [patent proprietor] is followed, the mere disclosure of a meaning in the description – i.e. previously purified to a high or very high degree of purity, see point  above – would allow to interpret in a limitative way the expression “previously purified” in claim 1.
 According to the Board, the term “interpretation” in A 69(1) cannot possibly be interpreted in such a way as to justify such an approach (in this context, also see Case Law, 6th edition, 2010, II.B.5.3.4, second to seventh paragraphs). The Board is of the opinion that this already follows from the mere fact that A 69(1) stipulates that the description and drawings shall be used to interpret the claims. This article, therefore, implies that one has to attach great importance to the wording of the claims rather than to the wording of the description.
 As a consequence, claim 1 has to be interpreted in such a way that it [also] covers processes having previous purification steps that result in starting solutions the degree of purity of which is less than “high or very high”.
 Thus it follows from points  to  above that claim 1 extends to methods that are not comprised in the content of the application as originally filed.
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