T 1351/23 (Blinatumomab/AMGEN) 14-07-2025

1. The opposition division's decision not to admit auxiliary requests 2 to 5 and 7 to 11

1.1 Auxiliary requests 2 to 5 and 7 to 11 were filed on 26 January 2023, i.e. one day before the final date fixed by the opposition division under Rule 116 EPC. They were identical to auxiliary requests 6 to 9 and 11 to 15 filed with the reply to the notices of opposition. Auxiliary requests 2 to 5 and 7 to 10 contained dependent claims of the patent as granted that had been deleted in the main request and auxiliary request 1 filed on the same date. In addition, claim 1 of each of auxiliary requests 2 to 4 and 7 to 9 was broader than claim 1 of auxiliary request 1 in that the glucocorticoid (GC) was not limited to dexamethasone.

1.2 In its communication in preparation for the oral proceedings, the opposition division conveyed the preliminary opinion that auxiliary requests 6 to 15, now auxiliary requests 2 to 11, complied with the EPC (see page 1, point 3.3 and page 17, fifth line from the bottom). Nevertheless, at the oral proceedings, the opposition division decided not to admit auxiliary requests 2 to 5 and 7 to 11 for three reasons (decision, points 25.2, 26 and 30): (i) auxiliary requests 2 to 5 and 7 to 10 reinstated dependent claims that were not present in the main request and auxiliary request 1; (ii) auxiliary requests 2 to 4 and 7 to 9 were not convergent with auxiliary request 1 because they did not limit the GC to dexamethasone; and (iii) auxiliary requests 7 to 11 raised a clarity issue that had already been discussed for auxiliary request 6 at the oral proceedings.

1.3 In accordance with Article 12(6) RPBA, the Board should not admit requests which were not admitted in the proceedings leading to the decision under appeal, unless the decision not to admit them suffered from an error in the use of discretion or unless the circumstances of the appeal case justify their admittance.

1.4 It is established case law of the Boards of Appeal that the primary facts to be considered by an opposition division when admitting or disregarding claim requests filed at late stages of the opposition proceedings are the point in time at which the claim requests were filed and whether they prima facie overcome the outstanding objections. In relation to the point in time at which the claim requests were filed, the opposition division may also need to assess whether the claim requests were filed in response to a change in the proceedings, whether the opponents and the opposition division had sufficient time to consider the amendments and whether the late filing of the claim requests could constitute an abuse of procedure (Case Law, 10th ed., 2022, IV.C.5.1.4(d) and 11th ed., 2025, IV.C.5.1.7).

In the Board's view, the opposition division did not correctly apply these principles when it decided not to admit auxiliary requests 2 to 5 and 7 to 11 into the proceedings.

1.4.1 The opposition division failed to take proper account of the circumstances at the point in time at which the claim requests were filed.

In point 25.2 of the decision, the opposition division correctly acknowledged that auxiliary request 2 could not be considered late filed. The Board agrees with this conclusion and holds that the same is true for auxiliary requests 3 to 5 and 7 to 11.

Auxiliary requests 2 to 5 and 7 to 11 had been initially filed as auxiliary requests 6 to 9 and 11 to 15 with the reply to the notices of opposition. This was the earliest possible opportunity for the appellant to file amendments in the opposition proceedings. The day before the final date fixed under Rule 116 EPC, the appellant promoted initial auxiliary requests 6 to 9 and 11 to 15 to auxiliary requests 2 to 5 and 7 to 11. This change of the appellant's case constituted an adequate response to the opposition division's preliminary opinion that initial auxiliary requests 6 to 9 and 11 to 15 complied with the EPC. In addition, the change streamlined the proceedings as they stood on the date at which said change was submitted since it involved withdrawing several higher-ranking requests and promoting claim requests that the opposition division had preliminarily considered allowable.

Under such circumstances, the position that auxiliary requests 2 to 5 and 7 to 11 were late filed can hardly be defended. The Board also notes that the opposition division and the respondents have never argued that the number or nature of the amendments in auxiliary requests 2 to 5 and 7 to 11 constitute an abuse of proceedings, nor that they did not have enough time to deal with the amendments before the oral proceedings.

However, despite considering that auxiliary request 2 was not late filed, the opposition division held that this was immaterial for the issue of admittance. This conclusion is surprising since neither Article 114(2) EPC nor Rule 116 EPC gives the opposition division discretion to disregard submissions that were filed in due time. For this reason alone, the decision not to admit auxiliary requests 2 to 5 and 7 to 11 was flawed.

1.4.2 With regard to the question of whether auxiliary requests 2 to 5 and 7 to 11 were prima facie suitable to overcome the objections raised up to the time of their filing, the decision under appeal does not provide any reasons. However, it is clear that the requests had to be regarded as prima facie suitable to overcome those objections since the opposition division had considered in its preliminary opinion that they complied with the EPC.

1.4.3 The reasons put forward by the opposition division for disregarding auxiliary requests 2 to 5 and 7 to 11 were set out in points 25.2, 26 and 30 of the decision under appeal. These were also the reasons raised by the respondents in these appeal proceedings. First, it was argued that auxiliary requests 2 to 5 and 7 to 10 contained dependent claims that had been removed in the main request and auxiliary request 1. Second, it was argued that auxiliary requests 2 to 4 and 7 to 9 were not convergent with auxiliary request 1 because they did not contain the limitation that the GC was dexamethasone.

Neither of these reasons can prevail over the consideration that the auxiliary requests were filed in due time and prima facie relevant.

In point 30 of the decision, an additional reason was mentioned against auxiliary requests 7 to 11, namely that they contained a feature that had been found unclear in the discussion of auxiliary request 6 at the oral proceedings. This reason does not take account of the fact that auxiliary requests 7 to 11 were filed in due time - not at the oral proceedings. The discussion of auxiliary request 6 at the oral proceedings could not retroactively render auxiliary requests 7 to 11 inadmissible.

1.5 Therefore, the Board decided to set aside the opposition division's decision not to admit auxiliary requests 2 to 5 and 7 to 11 and admitted the requests in accordance with Article 12(6), first paragraph, RPBA.

2. Remittal (Article 111 EPC)

The patent proprietor and respondent 1 requested that the case be remitted if any of auxiliary requests 2 to 5 and 7 to 11 were admitted and any of auxiliary requests 2 to 11 were found to meet the requirements of Article 84 EPC.

Respondent 2 requested that the case be remitted if the opposition division's decision not to admit auxiliary requests 2 to 5 and 7 to 15 was reversed, i.e. even before assessing whether the auxiliary requests comply with Article 84 EPC.

The issue of the clarity of auxiliary request 6 decided by the opposition division was identical to that raised against auxiliary request 2. Therefore, the Board concluded at the oral proceedings that the issue of clarity had to be discussed before remittal and that if any of auxiliary requests 2 to 11 were found to comply with Article 84 EPC, there were special reasons within the meaning of Article 11(1) RPBA to remit the case to the opposition division for further prosecution.

3. Auxiliary request 2 - clarity (Article 84 EPC)

The respondents raised two points against the clarity of claim 1 of auxiliary request 2. First, the interpretation of the time at which the GC is administered with respect to the CD3 binding domain, namely that "the GC is administered prior to the administration of the first dose of the CD3 binding domain and prior to the administration of the second dose of the CD3 binding domain". Second, the meaning of the phrase "the second dose exceeds the first dose".

3.1 With regard to the time of administration of the GC in relation to the administration of the CD3 binding domain, the respondents considered that claim 1 could be interpreted in three different ways. The GC was administered:

(i) only once before the first dose of the CD3 binding domain,

(ii) twice before the first dose of the CD3 binding domain, and

(iii) once before the fist dose and once between the first and the second dose of the CD3 binding domain.

In the Board's view, option (iii) is the only reasonable interpretation. If all three options or either of options (i) and (ii) were meant as possible embodiments, then the claim did not need to specify that the GC was administered before the second dose of the CD3 binding domain. The specification that the GC is administered not only prior to the first dose of the CD3 binding domain but also prior to the second dose can only be reasonably construed as meaning that the GC is administered once before the first dose and once between the first and the second dose. Interpreting claim 1 as encompassing options (i) and (ii) is more of a semantic exercise than an interpretation of what the skilled person would realistically understand when reading the claim.

The fact that the patent contains examples in which the GC is administered only prior to the first dose does not change this conclusion. Claim 1 of auxiliary request 2 is limited with regard to claim 1 as granted, which did not refer to a second dose. The embodiments in which the CD3 binding domain is administered only prior to the first dose could be covered by claim 1 as granted but are no longer claimed by auxiliary request 2.

Therefore, the Board holds that the feature relating to the time of administration of the GC in claim 1 of auxiliary request 2 is clear and means option (iii).

3.2 With regard to the meaning of the phrase "the second dose exceeds the first dose", the wording of claim 1 is in itself clear. The skilled person in the field of therapeutic uses understands that the dose of an active ingredient is the amount of that active ingredient that is administered to the patient at one time or within a specified period of time. Although a dose can be administered in shorter or longer periods of time, it is unambiguous that a second dose that exceeds a first dose means that the amount administered with the second dose is greater than the amount administered with the first dose.

3.2.1 The respondents argued that paragraphs [0063] and [0064] of the patent rendered the meaning of the phrase unclear because, within the meaning of the patent, they taught that a second dose that exceeds a first dose meant that the second dose was administered for a longer period of time than the first dose rather than in a greater amount. In this context, the respondents referred to the recent decision of the Enlarged Board of Appeal G 1/24, which establishes how to use the description to interpret the claims. The order of G 1/24 states that:

"The claims are the starting point and the basis for assessing the patentability of an invention under Articles 52 to 57 EPC. The description and drawings shall always be consulted to interpret the claims when assessing the patentability of an invention under Articles 52 to 57 EPC, and not only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation."

3.2.2 In line with G 1/24, the Board has consulted the description when interpreting claim 1, in particular the paragraphs discussed by the parties, which read as follows:

"[0063] In a preferred embodiment, a first dose of the CD3 binding domain is administered for a first period of time; and optionally consecutively a second dose of the CD3 binding domain is administered for a second period of time, wherein the second dose exceeds the first dose.

[0064] The term 'exceeds' means that the second period of time is at least one day longer than the first period of time."

Paragraphs [0063] and [0064] refer to a preferred embodiment in which the second dose is greater than the first dose, a greater dose meaning that it is administered for a longer period of time. Such a preferred embodiment is not incompatible with the clear meaning of claim 1 indicated in point 3.2 above, which is the starting point and the basis for assessing the patentability of an invention in accordance with G 1/24. The teaching of paragraphs [0063] and [0064] does not raise doubts as to the overarching understanding that when a second dose exceeds a first dose, the amount administered with the second dose is greater than that administered with the first dose. The time aspect in paragraph [0064] has to be understood as relating to a preferred embodiment which contains an additional limitation as to the time within which the doses are administered relative to each other. Such a limitation is merely preferred and remains within the bounds of the prevailing meaning of claim 1 that the amount administered with the second dose is greater than that administered with the first dose. Therefore, paragraphs [0063] and [0064] do not change the clear meaning of claim 1 or render it ambiguous.

As noted by the appellant, the interpretation that claim 1 describes a dose escalation regimen in which the amount administered with the second dose is greater than the amount administered with the first dose is confirmed by the dependent claims, which are also silent on the length of the administration period.

4. In view of the conclusions in points 2 and 3 above, the Board decided to remit the case to the opposition division for further prosecution on the basis of auxiliary request 2.