T 1913/21 - The claim says 'use of', but is it a use claim?

 Key points

• More precisely, is the following claim a valid second non-medical use claim in the sense of G 2/88: "Use of an inhibitor of cysteine degradation for reducing the formation of trisulfide bonds in proteins, wherein the inhibitor of cysteine degradation is [compound X]; and wherein the use comprises: culturing cells expressing said proteins in the presence of an effective amount of the inhibitor of cysteine degradation, whereby trisulfide linkage formation in said proteins is reduced relative to cells cultured in medium without the inhibitor of cysteine degradation."
• The Board combines two aspects of G 2/88. Decision G 2/88 dealt with Art. 123(3) and with Article 54(1). The Art. 123(3) issue was about whether you can amend a claim in the patent as granted directed to a compound into a use claim (use of that compound for ...) without violating Article 123(3), i.e. 'change of category'.
• Regarding the change of category, question (ii) in G 2/88 was "Can a patent with claims directed to a "compound" and to a "composition including such compound" be amended during opposition proceedings so that the claims are directed to the "use of that compound in a composition" [without violating Article 123(3) EPC]. In that respect, the Enlarged Board considered the effect of Article 64(2) EPC and found the amendment admissible provided that a use claim in reality defines the use of a particular physical entity to achieve an "effect", and does not define such a use to produce a "product"" because in the former case, "the use claim is not a process claim within the meaning of Article 64(2) EPC"
• Come to think about it, I wonder whether the interpretation of the term 'process' in Article 64 (2) isn't properly the domain of the national courts.
• The third question concerned the novelty of the use claims and was answered as follows: "A claim to the use of a known compound for a particular purpose [*] should be interpreted as including that technical effect as a functional technical feature"
• * =  "which is based on a technical effect which is described in the patent"
• The present Board:  "It is apparent from this that the Enlarged Board's findings relating to new uses of known compounds are limited to uses/methods/processes which are not processes resulting in products, as referred to in Article 64(2) EPC."
• I don't know how apparent this is.
• There is case law that G 2/88 does not apply to claims reciting "use of a process" (link) but I'm unaware about case law about claims directed to "use of compound X in a process". 
• " It is further apparent that claims which when correctly construed are directed to processes resulting in products referred to in Article 64(2) EPC are not subject to the special treatment established under G 2/88 and G 6/88, even if they contain the word "use"."
•  "The board considers that the proteins produced by the claimed process would be covered by Article 64(2) EPC as "products directly obtained" by the claimed process. The board concurs in this regard with the findings in T 892/94 (Reasons 3.8) that applying the concept of novelty developed in G 2/88 to claims for processes of producing a product, even when drafted as use for achieving a technical effect that results in an improved product could potentially result in a permanent monopoly of the use of a known substance for a known purpose. Such a permanent monopoly would arise from the repeated drafting of claims for a process of production including a new, possibly only subtly different, technical effect associated with this known process (see also T 1179/07 cited above, Reasons 2.1.3)."
• Given that a claim must still be novel and inventive, I find this reasoning difficult to follow. However, the Board appears to cite T 0892/94 here. 
• "The board must determine whether or not the "use" of claim 1 is in fact a process to produce a product or if it is a use to achieve a (new) technical effect"
•  "In the present case (and as was the case for claim 1 of auxiliary requests XI and XII in T 308/17), the choice of drafting the claim as a "use" of chemical compound cannot mask the fact that the claim defines a production process and the new technical effect can only take place in the context of this process. The mere formatting of the claim to give the appearance that its subject-matter falls under the principles established by G 2/88 cannot circumvent the fact that on analysis, the claim is directed to a use or process for the production of a product, here one having the 'improved' property of having 'fewer' trisulfide bonds."
• "Thus the new technical effect recited in the claim of reducing the formation of trisulfide bonds in proteins pertains to the product (the protein produced) and cannot be considered a technical limiting feature of the "use" according to G 2/88. Indeed, where an invention relates to a new technical effect of a physical entity that can only occur as part of a process for the production or manufacture of a product, such that this effect is inextricably linked to and cannot occur in isolation from the production process, a claim directed to that "use" of the physical entity to achieve that effect must be regarded as directed to the production process per se."
• "The assessment of novelty in the present case will therefore be done by answering the question of whether or not there was a disclosure forming part of the state of the art of a process having the same physical steps (culturing cells expressing said proteins in the presence of an effective amount of a compound that may act as an inhibitor of cysteine degradation) and leading to the production of the product defined in the claim."
• "In view of the above considerations on claim construction, the subject-matter of claim 1 lacks novelty over the disclosure in documents D3 and D24"

EPO 

The link to the decision can be found after the jump.

https://www.epo.org/en/boards-of-appeal/decisions/t211913eu1