T 0419/16 - Inventive step of first medical use

Key points

• The decision deals with inventive step of a first medical use claim in the format of Article 54(4) EPC.
• "The purpose given in the claim is "for use as a medicament". The board also notes that according to the patent, the claimed antagonist is useful specifically in the treatment of "a disorder or condition selected from the group consisting of asthma; allergy; multiple sclerosis; or arthritis" (see paragraph [0011] and claim 4 of the patent as granted). "
• Claim 1 is, moreover, a functional antibody claim: "1. An antagonist of IL-33 for use as a medicament, wherein the antagonist comprises a binding composition from an antibody that specifically binds to IL-33."
•  The opposition division came to a positive decision on inventive step, assessed solely when starting from the disclosure in document D6 representing the closest prior art. The appellants [opponents] however consider the disclosure in several (different) documents (documents D3, D4 or D6/D10) as starting points for assessing inventive step."" 
• "Although assessing inventive step only from one closest prior art disclosure may constitute an efficient approach to address the situation where multiple similar disclosures were presented as starting points for the assessment of inventive step, it is, however, not an appropriate approach if the alternative starting points represent alternative and different routes to the invention, as they do in the case at hand. In such a situation, each starting point needs consideration because under Article 56 EPC, in order for an inventive step to be acknowledged, the claimed invention must not be obvious to a skilled person having regard to the state of the art, i.e. any prior art disclosure with the exclusion of documents under Article 54(3) EPC (see T 694/15, Reasons 13 to 15, T 816/16, Reasons 3.7.1 and T 261/19, Reasons 2.5)."
• For inventive step over D6: "the difference between this [antibody of D6] and the claimed antibody is the target (ST2/IL-33 receptor) and its medical use(s) both in general and the specific uses identified in the description of the patent (treating asthma, allergy, multiple sclerosis and arthritis)."
• "The objective technical problem that arises out of the above differences and their technical effects can be formulated as the provision of a medicament, e.g. for treating asthma, allergy, multiple sclerosis and arthritis."
• The decision is interesting because for inventive step of product claims, we normally consider only at the use mentioned in the description. 

EPO 

The link to the decision and an extract of it can be found after the jump.

https://www.epo.org/en/boards-of-appeal/decisions/t160419eu2

Inventive step (Article 56 EPC)

21. Claims 1 and 2 of auxiliary request 1 are identical to the same claims of the main request, i.e. auxiliary request 2 before the opposition division. The opposition division held that the subject-matter of claims 1 and 2 would not have been obvious to the skilled person when starting from the disclosure in document D6 representing the closest prior art, considered either alone or in combination with the disclosure in documents D3 or D4.

22. Claim 1 is for an IL-33 antagonist binding composition from an antibody that specifically binds to IL-33, for use as a medicament (see point 8.). The patent discloses that it is useful specifically in the treatment of "a disorder or condition selected from the group consisting of asthma; allergy; multiple sclerosis; or arthritis" (see paragraph [0011] and claim 4).

Closest prior art

23. The opposition division came to a positive decision on inventive step, assessed solely when starting from the disclosure in document D6 representing the closest prior art. The appellants however consider the disclosure in several (different) documents (documents D3, D4 or D6/D10) as starting points for assessing inventive step.

24. Although assessing inventive step only from one closest prior art disclosure may constitute an efficient approach to address the situation where multiple similar disclosures were presented as starting points for the assessment of inventive step, it is, however, not an appropriate approach if the alternative starting points represent alternative and different routes to the invention, as they do in the case at hand. In such a situation, each starting point needs consideration because under Article 56 EPC, in order for an inventive step to be acknowledged, the claimed invention must not be obvious to a skilled person having regard to the state of the art, i.e. any prior art disclosure with the exclusion of documents under Article 54(3) EPC (see T 694/15, Reasons 13 to 15, T 816/16, Reasons 3.7.1 and T 261/19, Reasons 2.5).

Starting from document D6 and/or D10 as the closest prior art

25. Document D6 discloses a study of T1/ST2 (ST2), an orphan receptor of unknown function, expressed on the surface of murine T-helper type 2 cells (Th2) (see abstract). It reports the results of experiments, inter alia using an anti-ST2 mAb demonstrating that ST2 "is a crucial cell-surface receptor that is required for Th2 effector responses" (see page 896, left column, first full paragraph) and plays an important role in Th2-mediated inflammatory responses (see abstract). Disclosed is that ST2 may prove to be a novel target for the selective suppression of Th2 immune responses (ibid). Document D6 neither discloses that ST2 is the receptor for IL-33 nor any anti-IL-33 antibody that antagonises its activity or a medical use for an anti-ST2 antibody or for an anti-IL-33 antibody.

26. The disclosure in document D10 does not go beyond or is equivalent to that in document D6. The board therefore refers to document D6 only, but the same considerations apply equally for document D10.

27. The most similar product disclosed in document D6 to the claimed antibody is an anti-ST2 mAb (ibid). However, no general or specific medical use is disclosed for this antibody. The difference between this and the claimed antibody is the target (ST2/IL-33 receptor) and its medical use(s) both in general and the specific uses identified in the description of the patent (treating asthma, allergy, multiple sclerosis and arthritis).

28. The objective technical problem that arises out of the above differences and their technical effects can be formulated as the provision of a medicament, e.g. for treating asthma, allergy, multiple sclerosis and arthritis.

29. The appellants argue that the identification of IL-33 as the ligand of ST2 was an obvious solution to the objective technical problem of either providing of an alternative medicament or alternatively, the de-orphaning of the Tl/ST2 receptor in order to provide antibodies against its ligand. However, neither of these formulations is appropriate, since they are not derived from the difference between the claimed subject-matter and the disclosure in document D6 and the technical effects related to the difference.

30. The board however agrees with the conclusion on obviousness set out in the decision under appeal (see point 4.8), that, while undertaking a search for the ST2 ligand might have been desirable for the skilled person, it was however not known:

- what the ligand would be;

- what its specific biological functions would be; and

- whether (either agonistic or antagonistic) antibodies to the, as yet unknown, ligand could reasonably be expected to be useful as therapeutic agents.

31. There is no pointer in the disclosure in document D6 that would have motivated the skilled person to undertake the rather substantial research project of trying to identify the unknown ligand for the ST2 as a route to solving the above formulated problem and which could have directed the skilled person to the claimed invention.

32. The appellants' argument that the skilled person starting from document D6 would have had the incentive and the means to identify the then unknown ligand to ST2, especially because ST2 shared structural similarities with the IL-1 receptor family, is not relevant to the assessment of obviousness in the case in hand because it fails to take into account that identifying the ligand of ST2 was not the objective technical problem to be solved as formulated in point 28.

33. In conclusion, the claimed invention was not obvious to the skilled person starting from the disclosure in document D6 (and document D10) representing the closest prior art.