T 2223/10 (Antibody binding GM1 ganglioside-bound amyloid beta-protein/MEDICAL & BIOLOGICAL LABORATORIES) 19-03-2015

Admissibility of the appeal

1. According to established jurisprudence of the Boards of Appeal, the admissibility of an appeal may be assessed ex officio at any stage of the appeal proceedings (cf. decision T 15/01, OJ EPO 2006, 153; Reasons, point 1), and accordingly also during oral proceedings. The appellant's procedural objection against the late introduction of this point by the respondents cannot therefore be accepted.

2. The issue for the board is whether the statement setting out the grounds of appeal complies with

Rule 99(2) EPC, which stipulates that in its statement the appellant shall indicate the reasons for setting aside the impugned decision and the facts and evidence on which the appeal is based. In line with established jurisprudence of the Boards of Appeal this is understood to mean that the arguments have to be clearly and concisely presented to enable the board and the respondent to understand immediately why the decision under appeal is alleged to be incorrect, and on what facts the appellant bases its arguments. In this respect it is enough if the appellant presents sufficient reasons for at least one ground why the decision under appeal should be set aside (Case Law of the Boards of Appeal, 7th edition 2013,

section IV.E.2.6.3).

3. In the oral proceedings before the opposition division, the subject matter of the proprietor's then main request was attacked under the headings of added subject matter (Article 123(2) EPC), lack of novelty (both Articles 54(2) and 54(3) EPC), lack of inventive step (Article 56 EPC) and insufficiency

(Article 83 EPC).

The opposition division held that the subject matter satisfied the requirements of Article 123(2) EPC, was novel and inventive, but insufficiently disclosed. As regards the novelty attack, the opposition division inter alia held that the subject-matter was novel over the antibody 3D6 of document D5 mainly because there was (a) no explicit disclosure in this document that 3D6 recognised specifically amyloid beta-protein (Abeta) bound to GM1 ganglioside (GM1/Abeta) and inhibited amyloid fibril formation and (b) there was no other evidence available that unambiguously disclosed that the 3D6 antibody inherently possessed these two properties (see point 2.3 of the decision).

In this context, the opponent had filed declaration D25 in an attempt to prove that the 3D6 antibody did indeed inherently possess these two properties. However, it was not admitted into the proceedings because the opposition division held that the 3D6 antibody of declaration D25 was not identical to the one of document D5, and thus lacked prima facie relevance (see point 1.2.2 of the decision).

4. As regards the proprietor's first auxiliary request to maintain the patent in a more limited form, the only outstanding issue was then sufficiency, as to which the opposition division held that the requirements of Article 83 EPC were satisfied.

5. The appellant in its statement of grounds of appeal attacked the claims as maintained by the opposition division, arguing lack of novelty, lack of inventive step and insufficiency of disclosure. As regards lack of novelty, the attack was based on document D5, reliance now being partly placed on declaration D28 to establish that the 3D6 antibody of document D5 inherently had the properties of binding GM1/Abeta and inhibiting amyloid fibril formation.

It is readily apparent to the reader of the grounds of appeal that the declaration D28 was intended to overcome the problem with the declaration D25 (see the passage bridging pages 13 and 14 of the grounds of appeal). This is indeed how the respondents understood the matter (see the passage bridging pages 1 and 2 of their reply, dated 12 May 2011). Both declarations D25 and D28 report on the murine antibody 3D6 of document D5 and aim at assessing the properties of this antibody to bind to GM1/Abeta and to inhibit amyloid fibril formation. The murine 3D6 antibody of declaration D28 is asserted to be identical to the murine 3D6 antibody of document D5. Although the grounds of appeal do not refer explicitly to the reasons for the opposition division's decision, the argument about novelty is apparent to the reader, and was also apparent to the respondents (see above).

It was essentially the same argument as that which it had made before the opposition division, bolstered now by what was alleged to be shown by declaration D28. The reader gathers from this part of the grounds of appeal that the appellant is arguing that the opposition division was wrong about this issue. The fact that the argument relies partly on a new piece of evidence is immaterial for the present purposes, since this point relates to the admissibility of the evidence (see below). In the board's view, therefore, the reasons and evidence presented by the appellant were a direct response to the reasoning in the part of the decision on lack of novelty, and challenged its correctness.

6. Since the grounds of appeal therefore give adequate reasons why at least one ground for the decision was said to be wrong, it is not necessary to say anything about the respondents' argument concerning the new inventive step attack in the grounds of appeal based on document D29.

7. The appeal is therefore admissible.

Non-admissibility of declaration D28 and document D29

8. The declaration D28 and document D29 were filed by the appellant for the first time with its statement of grounds of appeal. According to the Rules of Procedure of the Boards of Appeal they are therefore part of the appeal proceedings (see Articles 12(1) and (4) RPBA). The respondents requested that both documents be not admitted into the proceedings, relying on Rule 76(2)(c) EPC. However, Rule 76(2)(c) EPC is not an automatic bar to the filing of new documents by an opponent after the expiry of the 9-month opposition period. For present purposes what is relevant is Article 12(4) RPBA, which refers to the power of the Boards of Appeal to hold inadmissible, i.e., exclude, evidence filed for the first time with the statement of grounds of appeal and which could have been filed during the first instance proceedings.

9. The declaration D28 discloses a murine 3D6 antibody which is allegedly structurally identical to the murine 3D6 antibody of document D5 and seeks to overcome the objection against the declaration D25 upheld by the opposition division during the oral proceedings (see point 1.2.2 of the decision). The appellant could thus not reasonably have filed the declaration D28 earlier than with its statement of grounds of appeal.

10. The respondents also argued, first, that the declaration D28 should not be admitted because it was prima facie not relevant since the murine 3D6 antibody used there was not identical to the murine 3D6 antibody of document D5. Second, even if it was identical, the murine 3D6 antibody of document D5 did not enjoy a valid priority. However, the declaration D28 seeks to establish that the murine 3D6 antibody of the document D5 inherently has the property to bind GM1/Abeta and to inhibit amyloid fibril formation, i.e. two functional properties which are referred to in claim 1, and is therefore prima facie relevant. Whether the respondents' two points are valid belongs to the discussion on the substantive appeal (see points 16 and 17, below), and not to the issue of admissibility.

11. Therefore the board decided not to exclude the declaration D28 from the proceedings pursuant to Article 12(4) RPBA.

12. The document D29 was cited for the first time in the grounds of appeal as part of a new inventive step attack, according to which it was said to represent the closest prior art. However, during the oral proceedings before the board the appellant stated that it no longer relied on this line of attack but rather that it would use the document D29 only in combination with document D2, D2 now being taken as the closest prior art. The document D2 had also been taken as the closest prior art by the opposition division in its decision. This change of case (from an attack based on document D29 as closest prior art to one based on document D2) was not as such objected to by the respondents.

13. The document D29, which was in fact cited in the patent as background art (see paragraph [0007]), is a scientific report of the inventor and disclosed for the first time that GM1/Abeta forms amyloid fibrils via a seeded polymerisation and that this "seed" could be a target for treating Alzheimer's disease (AD). The appellant's change of case and the reliance on document D29 did not raise new issues which either the board or the respondents could not deal with without an adjournment of the oral proceedings. The document D29 is also technically prima facie relevant because of its explicit disclosure of GM1/Abeta as a therapeutic target in the treatment of AD (see page 24989, column 2, last paragraph). The board therefore decided not to exclude document D29 from the proceedings pursuant to

Article 12(4) RPBA.

Novelty (Article 54 EPC)

14. Document D5 is a document according to

Article 54(3) EPC disclosing the mouse monoclonal antibody 3D6. It neither discloses that the murine 3D6 antibody binds GM1/Abeta nor that this antibody inhibits the Abeta mediated formation of amyloid fibrils, i.e. the two functional properties recited in claim 1.

15. The declaration D28 is intended to establish that the 3D6 antibody disclosed in document D5 has these two properties. It reports that a mouse antibody denoted as "3D6" is a recombinant antibody having the variable light and heavy chains defined by SEQ ID NOs: 2 and 4 of document D5 and a constant region of the IgG2b isotype as disclosed in table 7 of document D5 (see page 2, point 7) which allegedly renders the antibody identical to the mouse 3D6 antibody of document D5.

The document D5, however, does not disclose the sequence information for the IgG2b constant region of the mouse 3D6 antibody and this information is likewise lacking from the declaration D28. Accordingly, the complete sequence of the mouse 3D6 antibody of document D5 and that of the denoted "3D6" antibody of the declaration D28 is not disclosed by these documents.

16. It is therefore not apparent whether the mouse 3D6 antibody of document D5 and the denoted "3D6" antibody of the declaration D28 are identical. The experimental evidence of document D28 is thus not appropriate to establish that the murine 3D6 antibody of document D5 has the two functional properties recited in claim 1.

17. The board cannot therefore conclude that the 3D6 antibody of document D5 falls under the subject-matter of claim 1. As a consequence thereof the question about the validity of the priority of the murine 3D6 antibody of document D5 has no bearing for the assessment of novelty and the board therefore does not decide on this issue.

18. The subject-matter of claim 1 is thus novel and complies with the requirements of Article 54 EPC.

Sufficiency of disclosure (Articles 100(b) and 83 EPC)

19. Claim 1 refers to an antibody that recognizes GM1/Abeta, inhibits the formation of amyloid fibrils by Abeta and is further characterised by amino acid sequences, including partial alterations thereof.

20. The description of the patent in suit discloses in paragraphs [0006], [0016] and [0074] a reference to document D2 which informs the skilled person about the source for isolating GM1/Abeta and a suitable immunisation and hybridoma protocol for obtaining further anti-GM1/Abeta antibodies according to the invention (see document D2, page 43, column 2, points 2.2 and 2.3). The patent also discloses screening assays to isolate antibodies binding to GM1/Abeta (see [0052] and [0053]) and assays assessing the isolated antibodies ability to prevent Abeta amyloid fibril formation (see [0057] to [0059]). The patent further discloses the protein and nucleic acid sequences of the antibody "4396c" having the functional properties and structural characteristics of the antibody of claim 1 (see figures 1, 2, 5 and 6).

In view of these passages, the board considers that the description of the patent in suit discloses sufficient information for the skilled person to obtain further anti-GM1/Abeta antibodies having the functional and structural characteristics of claim 1, in particular antibodies that "recognise" GM1/Abeta and "inhibit the formation of amyloid fibrils". The disclosure of the nucleic and amino acid sequence of the "4396c" antibody moreover enables the skilled person to alter its sequence by standard mutational processes.

21. The board therefore disagrees with the appellant's objection that the functional and structural features in present claim 1, namely "recognising", "inhibiting the formation of amyloid fibrils" and "partial alteration" are not sufficiently disclosed. They are also considered to be standard terms in the antibody field. The appellant's further objection that the terms are unclear since the skilled person cannot determine whether an antibody falls within the range of claim 1 is in reality an objection of lack of clarity Article 84 EPC. However, this lack of clarity does not arise out of an amendment made in claim 1 as granted (in which the objected features are already present) and is therefore not an allowable objection. It must therefore fail.

22. The subject-matter of claim 1 thus complies with the requirements of Article 83 EPC.

Inventive Step (Article 56 EPC)

Closest prior art

23. In assessing whether or not a claimed invention meets the requirements of Article 56 EPC, the Boards of Appeal apply the "problem and solution" approach, which requires as a first step the identification of the closest prior art.

The parties agree that the disclosure of document D2 represents the closest prior art and the board sees no reason to differ.

24. Document D2 reports on a study aimed at determining the immunoreactivity of Abeta bound to GM1 (GM1/Abeta) and soluble Abeta (see page 43, column 2, first paragraph). GM1/Abeta is isolated from the brain of AD patients and used as an antigen for the preparation of the antibody "4397". The antibody differentiates between bound and soluble Abeta which implies a structural transition of Abeta upon its binding to GM1 (see page 43, abstract and column 2, column 2, points 2.2 and 2.3). A structural change of Abeta in the process of binding GM1 was also detected by optical means (see page 46, column 1, lines 29 to 31). It is not known from document D2 whether the "4397" antibody inhibits Abeta-mediated amyloid fibril formation.

Technical problem and solution

25. Thus, the antibody of claim 1 differs from the "4397" antibody in that it prevents Abeta-mediated amyloid fibril formation. The deposition of amyloid fibrils in neurons is one of the features found in brains of AD patients (see paragraph [0003] of the patent). In view of the closest prior art antibody and in view of the effects achieved by the antibody of the present invention - the technical problem to be solved is formulated as the provision of an anti-GM1/Abeta antibody with therapeutic applicability.

26. The board is satisfied that this problem is solved by the antibody of claim 1, which binds to GM1/Abeta and prevents amyloid fibril formation by Abeta, in view of the experimental data of example 4 and figure 6A of the patent in suit.

27. The appellant argued that the antibody of claim 1 lacked the feature "does not recognise soluble Abeta". The antibody would therefore bind to soluble Abeta, which however, was not involved in amyloid fibril formation. Hence, a substantial number of embodiments of claim 1 were not suitable for the treatment of AD and therefore did not solve the technical problem defined in point 25 above.

28. The board notes that the appellant has not submitted any evidence for its assertion that the antibody of claim 1 lacking the feature "does not recognise soluble Abeta" is in fact unable to achieve the inhibition of amyloid fibril formation mediated by Abeta. There is also no evidence available to the board showing that soluble Abeta is not involved in amyloid fibril formation. On the contrary, document D27 discloses that soluble Abeta forms amyloid fibrils (see figure 3).

Also the argument that the patent does not disclose a working example of an anti-GM1/Abeta antibody that inhibits amyloid fibril formation by binding to soluble Abeta does not support the appellant's case since there is no absolute requirement in the EPC for the presence of such an example.

The appellant further argued that the lacking feature constitutes an essential feature of claim 1 in the light of the declaration D21. However, the inventor refers in point 6 of the declaration to his understanding of the "claims in the subject application" involving "recombinant anti-GM/Abeta-antibodies" and their biological activity comprising, "i.e. recognition of Abeta bound to lipid vesicles containing GM1 ganglioside but not soluble Abeta or GM1". The board notes that none of the "claims of the application" in fact refer to anti-GM/Abeta-antibodies that do not bind soluble Abeta. The personal view of the inventor cannot therefore serve as a basis for concluding that claim 1 lacks an essential technical feature.

29. Consequently, in the absence of any convincing evidence that the inhibition of amyloid fibril formation cannot be achieved by the antibody of claim 1, the board has no doubt that the antibody has this property. Thus, the appellant's argument that the subject-matter of claim 1 encompasses a substantial number of non-working embodiments which do not solve the technical problem is not accepted by the board.

Obviousness

30. The question to be assessed is whether the skilled person, faced with the problem of providing an anti-GM1/Abeta antibody with a therapeutic applicability, would be motivated to do so when starting from the disclosure of document D2.

31. Document D2 discloses an anti-GM1/Abeta antibody that selectively binds to Abeta bound to GM1 but does not recognise soluble Abeta (see page 43, abstract). This antibody or antibodies with this property "may be useful probes to gain new insight into the initial molecular mechanism of Abeta deposition, including the generation of GM1/Abeta, in the brains of subjects with AD" (see document D2, page 46, column 1, lines 33 to 36). It further reports that "GM1/Abeta accelerates the the rate of amyloid fibril formation" (see page 46, column 1, lines 28 to 33). However, document D2 neither discloses that GM1/Abeta in fact triggers amyloid fibril formation by Abeta nor an anti-GM1/Abeta antibody that interferes with Abeta deposition or with the formation of Abeta-mediated amyloid fibrils, i.e. with any of the known molecular processes involved in the development of AD.

32. In the board's view, document D2 therefore contains no pointers for the skilled person to provide an anti-GM1/Abeta antibody with a therapeutic application. The subject-matter of claim 1 is therefore not obvious in the light of the teaching of document D2 alone.

33. Document D27 discloses that antibodies directed against aggregating epitopes of the soluble Abeta are able to inhibit the formation of Abeta amyloid fibrils (see abstract, figure 1 and page 454, column 1, last paragraph to column 2, second paragraph). However, it neither discloses GM1/Abeta nor an antibody that recognises Abeta bound to GM1 or an antibody that is able to inhibit GM1/Abeta's seeding activity.

Moreover, Abeta bound to GM1 has a different secondary structure than soluble Abeta (see document D2, page 46, column 1, lines 29 to 31) and it is not known whether the processes resulting in amyloid fibril polymerisation starting from soluble Abeta are identical to the ones starting from GM1/Abeta.

34. Accordingly, in the board's view, the skilled person in view of the teaching of document D27 would be likely to turn to antibodies binding soluble Abeta rather than to antibodies directed against GM1/Abeta. The subject-matter of claim 1 is thus not obvious in the light of the teaching of document D27 in combination with document D2 as closest prior art either.

35. Document D29 is the only available prior art document that refers to GM1/Abeta as a "seed" in the accelerated polymerisation process of amyloid fibrils and thus identifies GM1/Abeta as a potential therapeutic target in the treatment of AD (see page 24985, abstract; page 24989, column 2, last paragraph). This document reports, however, primarily on a study wherein the role of cholesterol in cell membranes is analysed in enabling GM1 to form clusters or GM1-enriched microdomains that act as binding sites for native Abeta and the pathological implications of an altered cholesterol metabolism in the development of AD (see page 24985, column 2, second paragraph; page 24989, column 1, second paragraph to column 2, first paragraph).

The results presented in this document suggest that an increase in cholesterol in the cell membrane of neurons induces the formation of GM1/Abeta and that "alterations in the content of cholesterol in neuronal membranes underlie the abnormal aggregation of Abeta in the AD brain" (see page 24989, column 2, second paragraph).

The board takes further note that document D29 states, in its ultimate paragraph on page 24989, column 2: 'To generate a compound that specifically recognizes GMl/Abeta and inhibits its seeding ability, it will be necessary to clarify the molecular processes underlying alterations of the secondary structures of Abeta via binding to and accumulation in GMl "clusters."'.

This paragraph neither discloses nor suggests an antibody suitable for inhibiting GM1/Abeta's seeding ability. Hence, the skilled person would by the combination of the teaching of document D2 with D29 not automatically arrive at the subject-matter of claim 1. In the board's view, the skilled person would also in the light of the teaching of this paragraph not be motivated to provide a GM1/Abeta recognising antibody for a therapeutic application before the underlying processes of how Abeta binds to GM1 and how it accumulates in clusters were elucidated.

36. The appellant argued that the skilled person had a reasonable expectation of success in arriving at an antibody that specifically recognizes GM1/Abeta and interferes with its seeding activity in view of the teaching of documents D2 and D29.

37. According to the established jurisprudence of the Boards of Appeal the assessment of obviousness in the context of a reasonable expectation of success requires that the skilled person would have followed an available teaching of the prior art which requires a scientific evaluation of the facts at hand to predict rationally the successful conclusion of such a project within acceptable time limits (see Case Law of the Boards of Appeal, 7th edition 2013, I.D.7.1).

38. In the case of a therapeutic agent interacting with a particular target this evaluation requires, according to the board's opinion, whether there are indications available in the prior art that an interference with the target has or will most probably have - since certainty is not required - a beneficial effect for the disease to be treated.

39. The board notes that the combined teaching of document D2 with that of D29 neither presents a model of how GM1/Abeta accelerates the process of amyloid fibril formation nor a concept providing the skilled person with an idea of how an antibody could interfere with GM1/Abeta to prevent the polymerisation process or Abeta's accumulation in GM1 cluster. Therefore document D29 does not provide facts concerning an antibody based GM1/Abeta interference. This document focuses on the importance of cholesterol in the "seeding" process, i.e. the initial binding of native Abeta to GM1 clusters (see point 34, above). In the board's view, the skilled person would therefore rather derive from document D29 that the control of cholesterol is a promising approach for the treatment of AD.

Hence, in the absence of any facts in document D29 regarding an anti-GM1/Abeta antibody and its effects on amyloid polymerisation, the skilled person is according to the board's view, unable to make a reasonable prediction about the outcome of a project focusing on antibodies that specifically recognise GM1/Abeta to interfere with GM1/Abeta's seeding activity. Thus, the board cannot agree with the appellant that the skilled person would have had a reasonable expectation of success so as to arrive at the subject-matter of

claim 1.

The subject-matter of claim 1 cannot therefore be considered obvious in the light of the combined teaching of documents D2 and D29.

40. Hence, the subject-matter of claim 1 involves an inventive step and complies with the requirements of Article 56 EPC. The same applies to the subject-matter of claims 2 to 16, which all depend on claim 1.