T 1080/20 28-11-2023

1. Appellant's request for oral proceedings

1.1 The respondent argued that the appellant's request for oral proceedings (in the appeal proceedings) should have been submitted already, within the meaning of Article 12(6) RPBA 2020, in the proceedings leading to the decision under appeal. This argument is flawed.

1.2 A party's request for oral proceedings in the appeal proceedings is different from that party's request for oral proceedings in the proceedings before the department of first instance. If a party, as in the present case, chooses not to avail itself of its right to oral proceedings before the department of first instance, it has to bear the consequences of that choice in that it must accept that that department may decide on the basis of that party's written submissions only. This, however, does not mean that such a party is then also barred from requesting oral proceedings in any ensuing appeal proceedings.

1.3 Hence oral proceedings were held in line with the appellant's request.

2. The patent

2.1 Errors in fluid removal during fluid removal sessions such as haemodialysis or haemofiltration may result from inaccurate determination of the patient's dry weight (i.e. the weight that the person would have if their kidneys were functioning properly) and may lead to severe risks for the patient.

2.2 The patent deals with monitoring fluid volume in blood and tissue compartments of patients during fluid removal sessions, and controlling the rate at which fluid is removed from blood based on the monitored fluid volumes. By maintaining a proper fluid balance between blood and tissue compartments, patient safety is enhanced and the efficiency of blood cleaning is increased.

3. Main request - admittance

3.1 The respondent requested that the main request not be admitted into the appeal proceedings. This request was not made in the reply to the statement of grounds of appeal but for the first time by a letter dated 29 June 2022, i.e. more than two years after the main request had been filed. The respondent argued that the main request should have been filed during the first-instance opposition proceedings, that it represented a fresh case and that it was not prima facie allowable because it infringed Article 123(3) EPC.

3.2 The main request was filed together with the statement of grounds of appeal and constitutes an amendment within the meaning of Article 12(4) RPBA. It directly addresses the Opposition Division's finding - of which the appellant only became aware when the decision under appeal was issued - that claim 1 as granted comprised added subject-matter. Furthermore, the amendment is directed to a combination of claims as granted. The claimed combination adds the features the omission of which resulted in added subject-matter according to the appealed decision. In view of these circumstances, the Board decided to exercise its discretion to admit the main request into the appeal proceedings.

4. Main request - Article 123(3) EPC

4.1 The respondent submits that the main request infringes Article 123(3) EPC because claim 1 of the main request extends the protection conferred by claim 1 as granted.

4.2 The protection conferred by both claim 1 as granted and claim 1 of the main request must be determined in accordance with Article 69 EPC and its protocol (G 2/88, Reasons 4).

4.3 The main point of dispute concerns the protection conferred by claim 1 as granted and, in particular, by the phrase "to determine a ratio of tissue fluid volume and blood fluid volume".

4.4 The respondent argued that this phrase limited the extent of protection to the determination of a ratio of volumes (e.g. measured in ml), and that it did not extend to the determination of indicators of such volumes.

4.5 The Board holds that this view can only result from understanding the extent of protection as being defined by the strict, literal meaning of the wording of claim 1 as granted, considered in isolation from the remainder of the patent. However, pursuant to Article 1, first sentence, of the Protocol on the Interpretation of Article 69 EPC, such an approach must not be applied.

4.6 The systems described in the patent specification may determine either a "ratio of the indicator of tissue fluid volume to the indicator of blood fluid volume" (see for example dependent claim 2, Figures 12 and 14, first sentence of paragraph [0061] as well as paragraph [0077]), or a "ratio of the value indicative of tissue fluid volume to the value indicative of blood fluid volume" (see for example dependent claim 3 as granted, Figure 13, as well as paragraphs [0059] and [0091]). The specification also teaches that use of the latter ratio requires a previous step of calculating the values indicative of tissue fluid volume and blood fluid volume based on the respective indicators (see paragraphs [0059] and [0060], Figure 13 and claim 3).

4.7 Contrary to the respondent's submission, the Board sees no reason why the dependent claims should be disregarded when determining the protection conferred under Article 123(3) EPC. On the contrary, when assessing whether an amendment extends the protection conferred by the patent, it is the totality of the claims as granted as compared with the totality of the claims after the amendment that has to be considered (G 2/88, Reasons 3.2). Therefore, even if the issue in dispute mainly concerns claim 1 as granted, the dependent claims should also be given due consideration. In the present case, they provide meaningful context for the interpretation of claim 1.

4.8 The structure of the claims as granted, with claims 2 and 3 depending from claim 1, indicates that the ratios specified in each of claims 2 and 3 are a specific case of the ratio in claim 1. Otherwise, claim 2 would have to be understood as being directed to a system configured to determine two different ratios, in contrast to the specification, which nowhere mentions any such system.

4.9 The specification, when describing the embodiment of Figure 12, which employs the ratio of indicators, consistently refers to "the ratio of tissue fluid volume and blood fluid volume" (see paragraphs [0053]-[0057]), which is the same wording used in claim 1. This strongly supports the disputed phrase of claim 1 encompassing the determination of a ratio of indicators (claim 2) and not only of a ratio of values indicative of volumes (claim 3). This is eventually confirmed by the specification when describing the embodiment of Figure 13 in paragraph [0059], in particular its third sentence, which reads as follows: "The ratio of tissue fluid volume to blood fluid volume may be determined based on these calculated values (530) [i.e. the values indicative of volumes] rather than on the values obtained with regard to the monitored indicators themselves as depicted in FIG. 12".

4.10 It follows that the phrase of claim 1 as granted "to determine a ratio of tissue fluid volume and blood fluid volume" does not limit the extent of protection to the determination of a "ratio of the value indicative of tissue fluid volume to the value indicative of blood fluid volume". Rather, the extent of protection also extends to the determination of a "ratio of the indicator of tissue fluid volume to the indicator of blood fluid volume".

4.11 Claim 1 of the main request calculates the "ratio of the indicator of tissue fluid volume to the indicator of blood fluid volume". For the reasons set out above, this ratio constitutes a specific ratio of the ratio which, according to claim 1 as granted, is determined by the control electronics. In other words, the amendment limits the determination of a generic ratio to the determination of a specific ratio, so the subject-matter of claim 1 of the main request corresponds to that of claim 2 as granted. In conclusion, the amendment to claim 1 does not extend the protection conferred by the claims as granted.

4.12 The same reasoning applies to claim 2 of the main request because the "ratio of the value indicative of tissue fluid volume to the value indicative of blood fluid volume" also constitutes a specific case of the ratio determined in claim 1 as granted.

4.13 It follows that the main request does not infringe Article 123(3) EPC.

5. Remittal

The appealed decision dealt only with the ground for opposition under Article 100(c) in view of Article 123(2) EPC for claim 1 as granted. As stated above, the only objection under Article 123 EPC raised by the respondent against the main request is not convincing. Hence the main request complies with the requirements of Article 123 EPC.

Both parties requested that the case be remitted for examination of substantive objections including objections of insufficient disclosure of the invention, lack of novelty and lack of inventive step. Since the decision did not deal with these objections, special reasons within the meaning of Article 11 RPBA present themselves for remitting the case to the Opposition Division for further prosecution under Article 111(1) EPC.