T 0308/14 - Binding effect covers finding of fact

EPO Headnote

If, in appeal proceedings, a case is remitted to the opposition division after the board has taken a decision under Article 84 EPC on the clarity of a certain feature in a claim - in the present case the weight average molecular weight of polysaccharides - this decision is res judicata and thus binding on the opposition division in the subsequently resumed opposition proceedings. The binding effect does not only cover the decision on Article 84 EPC as such; it also extends to any finding of fact that led to this decision. Therefore, if in the resumed opposition proceedings an insufficiency objection is made under Article 83 EPC on the basis that this very feature is ambiguous (insufficiency arising out of ambiguity), the opposition division should not reopen the discussion of whether this feature is clear, and should accept any finding of fact the board made in arriving at its decision on Article 84 EPC (point 1 of the Reasons). (emphasis added)

T 0308/14 - [C] - link

Reasons for the Decision

Main request

1. Article 83 EPC

1.1 The present appeal is the second appeal in this case. In decision T 1115/10 (point 9.3) on the first appeal, the board held that the feature "polysaccharides having a weight average molecular weight of not more than 10000" in claim 1 of the then second auxiliary request complied with Article 84 EPC. The board in particular reasoned as follows:

"... no proof has been provided that the alleged dependence exists also for these low weight average molecular weights. In the absence of any such proof, it can be assumed in the appellant's favour that the weight average molecular weight of not more than 10 000 in claim 1 does not depend on the measurement method. The inclusion of this weight average molecular weight in claim 1 therefore does not infringe the requirements of Article 84 EPC."

Hence, decision T 1115/10 contained the finding of fact that the weight average molecular weight of not more than 10 000 in claim 1 was clear in terms of Article 84 EPC since, taking into account the evidence on file, it did not depend on the measurement method applied.

1.2 After the board had remitted the case to the opposition division, various documents including D13a and D19 (D13a was denoted "D13" and D19 was denoted "Annex A - declaration" in these proceedings) were filed. The respondent argued on the basis of these documents that, in as far as the polysaccharides with a weight average molecular weight of not more than 10 000 were concerned, the invention lacked sufficiency of disclosure. In its decision, the opposition division agreed and reasoned that in view of D13a and D19 there were multiple measurement methods for the determination of the weight average molecular weight, and that the values so obtained depended on the type of method applied. The opposition division therefore decided that the main request (identical to the second auxiliary request in T 1115/10) did not comply with Article 83 EPC. The opposition division's decision was thus a decision on insufficiency arising out of ambiguity, namely the ambiguity of the weight average molecular weight in claim 1.

1.3 As set out above, it had already been finally decided in T 1115/10 that the requirements of Article 84 EPC were met. This decision constituted res judicata and thus was binding on the opposition division in the subsequently resumed opposition proceedings (Article 111(2) EPC). It was a matter of dispute between the parties whether the opposition division's decision on sufficiency contravened this binding effect of T 1115/10. The respondent argued that decision T 1115/10 only concerned Article 84 EPC and therefore did not bind the opposition division in its decision on Article 83 EPC.

The board does not agree. The binding effect of decision T 1115/10 does not only concern the decision on Article 84 EPC as such but extends to any finding of fact that led to this decision (T 843/91, headnote and point 3.4.2 and T 153/93, points 2 and 3), i.e. in the present case the finding that the weight average molecular weight in claim 1 did not depend on the measurement method. Therefore, the opposition division should not have reopened the discussion on this finding of fact when deciding whether any alleged ambiguity of the weight average molecular weight in claim 1 led to insufficiency, but should have accepted this finding as it stood. By not doing so, the opposition division violated the principle of res judicata and jeopardised the general interest of the public in the settlement of legal disputes.

1.4 This is not changed by the statement in the opposition division's decision (point 19.3) that "In T 1115/10 the board already expressed their concern about a possibly inconsistent measurement situation regarding Mw below 10 000 (p. 21-22, bridging paragraph)." This statement misinterprets decision T 1115/10, since a concern was expressed, if at all, only for high molecular weights namely 500 000 or above (first sentence of the last paragraph on page 21 of the decision).

1.5 The respondent argued that it had had very little time during the first appeal proceedings to make a proper insufficiency attack against the weight average molecular weight, and that it had completed this attack as early as possible once the opposition proceedings were resumed. The opposition division was thus correct in taking this attack into account and in denying sufficiency of disclosure.

The board does not agree with this argument. Firstly, the respondent did not dispute that it had not raised any objection during the first appeal proceedings that it had not had sufficient time to make its attack on sufficiency of disclosure. In fact, no such objection appears in T 1115/10. Secondly, the assertion that the attack was completed as early as possible has no bearing on the fact that T 1115/10 was binding on the opposition division.

1.6 In view of the above, the weight average molecular weight in claim 1 must still be considered not to depend on the measurement method applied. Consequently, the respondent's insufficiency attack, which starts from the opposite assumption, cannot succeed.

1.7 The appellant had requested that the decision of the opposition division to admit D19 (and reference documents D16 to D18) into the proceedings be set aside. The board agrees that the opposition division should indeed not have admitted these documents, since they were filed in order to reopen the question whether the weight average molecular weight in claim 1 depended on the measurement method. However, since, the respondent's insufficiency attack cannot succeed anyway, the board did not need to decide on the appellant's request.