T 1628/23 (Casein compositions/FRONTERRA) 06-11-2025

1. Admittance of evidence

1.1 Documents D14-D16

The opposition division admitted documents D14-D16 into the proceedings on the grounds that (i) the documents were filed by the opponent in response to the preliminary opinion issued by the opposition division within the time limit set under Rule 116 EPC; (ii) both parties relied on these documents to support their arguments concerning the issue of sufficiency; and (iii) the documents were considered helpful in understanding the claimed invention.

In its communication pursuant to Article 15(1) RPBA the Board indicated, with reference to Article 12(2) RPBA, that it did not recognize a basis for disregarding these documents in the appeal proceedings.

No substantive arguments were submitted by the patent proprietor in response to the preliminary opinion regarding documents D14-D16.

The Board has therefore confirmed that documents D14-D16 are part of the appeal proceedings.

1.2 Documents A20-A21

Documents A20 and A21 were filed by the opponent with the statement of grounds of appeal.

The admittance of documents A20 and A21 is therefore subject to the provisions of Article 12(4) and (6) RPBA. Under Article 12(6), second sentence, RPBA, the Board shall not admit evidence which should have been submitted in the proceedings leading to the decision under appeal, unless the circumstances of the appeal case justify their admittance.

The opponent argued that the submission of documents A20 and A21 represented a justified response to the finding in the decision under appeal that the claimed subject matter was new over document D13. This finding was based on the assessment that document D13 disclosed the use of calcium-depleted milk protein concentrate (MPC) in cheese production but did not describe the consumption of the resulting cheese and could therefore not implicitly disclose any biological effects of the calcium depleted MPC. The filing of documents A20 and A21 with the statement of grounds of appeal was justified, because the issue that document D13 did not disclose the consumption was raised for the first time during the oral proceedings before the opposition division. In the opponent's view, documents A20 and A21 were prima facie relevant, because these documents explicitly disclosed the ingestion of products containing calcium-depleted milk protein concentrate, and should therefore be admitted.

However, given the primary object of the appeal proceedings to review the decision under appeal in a judicial manner (Article 12(2) RPBA), it is the responsibility of the opponent to submit the evidence of the prior art supporting its case during the first-instance proceedings. In this context, it is established jurisprudence (see Case Law of the Boards of Appeal of the EPO, 11th edition, 2025, V.A.4.3.7.n) that new objections or evidence against claims as granted or against claims filed with the reply to the notice of opposition should have already been filed in the opposition proceedings. The opponent relies on documents A20 and A21 as new evidence that the subject-matter of claims 1 and 2 as granted lack novelty. Accordingly, these documents should have been filed during the first-instance proceedings.

Notably, the patent proprietor contested the prima facie relevance of documents A20 and A21, because these documents failed to disclose the effect of calcium-depleted MPC on blood leucine levels. The Board does therefore not recognize any circumstances of the appeal case that would justify the admittance of documents A20 and A21.

Accordingly, the Board has decided not to admit documents A20 and A21 under Article 12(6) RPBA.

2. Sufficiency

2.1 Claims 1 and 15 define the non-therapeutic and therapeutic utility of a casein composition, which comprises or is in the form of calcium depleted milk concentration or isolate (MPC or MPI), for increasing the blood serum concentration of leucine. Claim 2 defines the non-therapeutic utility of such a casein composition for increasing the rate of gastric emptying, the digestibility of a protein composition, or the rate of delivery of amino acids to the blood.

Although claims 1, 2, and 15 do not specify a particular baseline level for the defined increase in blood leucine level, the rate gastric emptying, protein digestibility, or amino acid delivery, the person skilled in the art would reasonably interpret these claims as requiring increases that significantly exceed an individual's physiological baseline.

This interpretation of the claims is consistent with the description of the invention in the patent, which explains that calcium depleted MPC can elevate blood leucine levels and enhance gastric emptying in a manner comparable to whey protein (see paragraph [0053]) and clarifies that increasing the blood serum concentration of leucine refers to maintaining and increasing blood leucine concentrations, preferably to adequate physiological concentrations to maximally stimulate muscle protein synthesis in the post-prandial period (see paragraph [0058]).

Therefore, the opponent's contention that the claims lack a defined baseline level amounts to a clarity objection but does not effectively challenge the sufficiency of the patent's disclosure of the claimed invention.

2.2 Example 1 of the patent compares changes in the blood leucine levels up to 180 minutes after consumption of equivalent amounts of leucine from (A) calcium-depleted MPC, (B) whey protein concentrate from cheddar cheese manufacture (WPC), (C) standard MPC, and (D) calcium caseinate. The results are presented in Figures 1-4, with Figure 1 reproduced below.

FORMULA/TABLE/GRAPHIC

As noted in paragraph [0136] of the patent, the peak leucine concentrations and the amino acid availability within the first 60 minutes were significantly higher after consumption of calcium-depleted MPC and WPC compared to standard MPC or calcium caseinate.

Example 3 of the patent provides a further comparison of the changes in blood leucine levels after the consumption of equivalent amounts of leucine from (A) whey protein concentrate from cheddar cheese manufacture, (B) calcium-depleted milk protein concentrate, (C) standard milk protein concentrate, and (D) sodium caseinate. The results are presented in Figures 5-7, with Figure 5 shown below.

FORMULA/TABLE/GRAPHIC

According to the patent (see paragraph [0148]) the results from Example 3 demonstrate that the maximum blood leucine levels following consumption of the calcium depleted MPC, sodium casein and WPC were significantly different to the maximum blood leucine level following consumption of standard MPC and that the availability of amino acids in the first 90 minutes was significantly greater following the consumption of calcium depleted MPC than following the consumption of standard MPC.

These conclusions are confirmed by document D15 (see page 1512, left column and page 1517, left column) and the declaration in document D16 (see D16, page 4, sections 13 and 14).

Document D14 further supports the enhanced gastric emptying associated with calcium-depleted MPC. Under simulated gastric conditions, standard MPC, which contains intact casein micelles, formed dense, cohesive curds within 10 minutes. In contrast, partially calcium-depleted MPC, which lacked an intact micellar structure, produced curds only after 40 minutes, and these exhibited a loose, fragmented structure upon continued digestion (see D14, page 6842, Abstract).

In view of the evidence presented in the patent, the opponent's objection that the patent fails to demonstrate a significant increase in the levels of blood leucine from calcium depleted MPC relative to standard MPC and calcium caseinate and that claimed enhancement in gastric emptying is not credible, remains unsubstantiated. Moreover, the objection that the application does not plausibly demonstrate the ability of the defined composition to raise free leucine concentrations in blood serum to up to 400 mymol/L, as specified in granted claim 6, is equally unconvincing in light of the results from Examples 1 and 3.

2.3 The opponent argued that it was not plausible that the increase in blood leucine concentration could achieve the effect of an increase in muscle protein synthesis as defined in claims 12 and 15 of the patent.

However, the patent explains, with reference to relevant literature, that essential amino acids (EAAs) play a central role in regulating muscle protein synthesis, with leucine specifically recognized as particularly important for stimulating this process (see paragraphs [0004]-[0005]). Document D12, which is in this context cited in the patent, confirms that whey protein serves as a faster and more efficient source of leucine than caseinate and refers to multiple studies in which whey protein was found to be superior to casein in stimulating whole-body protein synthesis (see D12, page 7, right column to page 8, left column). Similarly, document D15 reports that whey protein may provide superior post-exercise muscle protein synthesis (MPS) compared to casein (see page 1517, right column). Given the experimental results from Examples 1 and 3, which show that calcium-depleted MPC induces a rapid increase in blood leucine levels comparable to whey protein, it is therefore reasonable to conclude that the effect of enhanced muscle protein synthesis as underlying the use defined in claims 12 and 15 can be achieved with calcium-depleted MPC. This conclusion remains valid despite findings in documents D12 and D15 indicating that, under specific experimental conditions, the use of whey protein or calcium depleted MPC was not found to provide a higher anabolic response than casein or standard MPC.

2.4 As set out in the decision under appeal (see pages 8-9, bridging paragraph), satiety refers to the feelings of fullness between meals whereas satiation indicates feelings of fullness during ingestion. In view of these definitions of the terms satiety and satiation, no contradiction between the increased satiety and reduced satiation defined in claim 12 as effects of the use of calcium depleted MPC is apparent.

2.5 As further pointed out in the decision under appeal (see page 8), the patent provides with respect to the calcium depletion of the casein composition a definition in paragraph [0054] and instructions in paragraphs [0069]-[0072]. The opponent's argument regarding this feature amounts to an objection of lack of clarity rather than an objection of lack of sufficient disclosure.

2.6 Accordingly, the Board finds that the opponent has not raised any serious doubts as to whether a skilled person would be able to carry out the claimed invention without undue burden and concludes that the patent as granted satisfies the requirement of sufficient disclosure (Articles 100(b), 83 EPC).

3. Novelty

3.1 Document D7

Document D7 investigates the amino acid absorption rates following dietary protein digestion and the subsequent postprandial response in muscle protein syntheses in young and elderly men. The document reports an increase in the blood leucine concentration and a subsequent muscle protein synthetic response following the ingestion of a single bolus of labelled micellar casein protein digestion in both groups of subjects (see D7, page 1710, Figure 2D and page 1712, right column).

The subject-matter of the claims of the patent differs from the teaching of document D7 in that it concerns the use of calcium depleted MPC instead of micellar casein.

The claims of the patent define a casein composition which comprises or is in the form of calcium depleted MPC or MPI. According to the textbook information presented in document A19, MPC is a spray dried powder manufactured from skim milk by ultrafiltration/diafiltration (UF/DF), wherein casein is present in a similar, micellar, form as found in milk (see A19, pages 315-316, section 13.3.6). Document D8 indicates that the calcium content in MPC may be reduced by more than 10% with respect to skim milk powder (SMP). The claims of the patent require, however, a product in which the MPC or MPI itself has been modified by the defined reduction of 10% or more of its calcium content. As confirmed by documents D14 and D15, the micellar structure of the casein in MPC is disrupted in calcium reduced MPC (see D14, page 6842, abstract and right column; D15, page 1512, left column and page 1513, left column). Accordingly, the micellar casein as described in document D7 cannot be equated to calcium depleted MPC as defined in the claims of the patent.

The description of the patent suggests in paragraph [0023]:

"In various embodiments the casein composition comprises a calcium depleted casein composition; calcium depleted skim milk; calcium depleted skim milk powder; calcium depleted whole milk; calcium depleted whole milk powder; caseinate, sodium caseinate, potassium caseinate, zinc caseinate, magnesium caseinate; a milk protein concentrate or isolate that has been modified to dissociate casein micelles; non-micellar casein; a casein ingredient, such as an MPC or MPI, where at least a portion of the calcium or phosphate or both the calcium and phosphate has been replaced with sodium, potassium, zinc, magnesium and like, or a combination of any two or more thereof; an acid soluble casein; a non-micellar caseinate; chelated casein micelles; a charge-modified casein; a glycosylated casein; a casein modified to decrease its ability to form a coagulum at acid pH, preferably at a pH below pH 5, pH 4, or pH 3; a casein modified to speed its ability to be hydrolysed in the gastrointestinal tract; a casein ingredient with an altered ratio of casein to whey; a lactic acid casein; a mineral acid one or more casein fractions; an alpha-casein fraction; a beta-casein fraction; a kappa-casein fraction; or any combination of any two or more thereof."

It is immediately evident that this list of embodiments, which is not limited to calcium depleted MPC or MPI, cannot be considered as a basis for the interpretation of the casein composition as defined in the claims of the patent, which explicitly refer to calcium depleted MPC or MPI. At the same time, insofar as this passage in the description mentions embodiments relating to MPC or MPI, it refers to modified forms thereof in which casein micelles are dissociated or at least a portion of the calcium or phosphate has been replaced with sodium, potassium, zinc, magnesium and like. Accordingly, paragraph [0023] of the patent cannot serve as a basis for an interpretation of the claims as encompassing the use of micellar casein as mentioned in document D7.

The Board therefore concludes that document D7 does not disclose the subject-matter of the claims of the patent as granted, which is thus novel over document D7 (Articles 100(a), 54 EPC).

3.2 Document D13

Document D13 discloses the use of calcium depleted MPC in the manufacture of cheese (see D13, page 2, lines 7-33). The stated purpose of this use is to improve processing properties, to provide cheese with a high protein content while avoiding nugget formation (see D13, page 5, lines 1-12). Document D13 does not address nutritional effects following consumption of the resulting cheese product.

As explained in section 2.1 above, independent claims 1, 2, and 15 of the patent define the use of calcium depleted MPC or MPI to achieve the physiological benefit of an increase in blood leucine level, gastric emptying, protein digestion or amino acid delivery which significantly exceeds an individual's physiological baseline.

The Enlarged Board of Appeal established in G 2/88 and G 6/88 that a claim directed to the use of a known composition for a new purpose is considered novel if the new purpose reflects a new technical effect. The claimed use of calcium depleted MPC to achieve the relevant physiological benefit as defined in the claims is neither explicitly nor implicitly disclosed in D13. The mere fact that cheese is intended for consumption does not render the claimed effect inherent. As emphasized in T 1523/07 (reasons 2.4), an implicit disclosure requires that the feature or effect be the inevitable result of what is explicitly disclosed in the prior art. Document D13 focuses on processing advantages and does not disclose the specific physiological benefits following ingestion as defined in the claims of the patent. Therefore, even if it is acknowledged that the consumption and digestion of cheese results in amino acid absorption, the specific technical effects defined in the claims remain undisclosed in D13 and cannot be regarded as an inevitable consequence of its teaching.

The claimed subject-matter is therefore new over document D13 (Articles 100(a), 54 EPC).

3.3 Document D10

In the notice of opposition, the opponent challenged the novelty of the claimed subject-matter based on documents D7 and D13. The objection relying on D13 was reiterated in the letter dated 14 July 2022, in which the opponent stated that an increase in blood serum concentration of free leucine is a known effect of ingesting a protein source. The letter also briefly asserted: "In that regard, the same applies to the calcium-depleted casein composition used in D10." However, during the oral proceedings before the opposition division (see minutes, sections 9-11), the opponent maintained its novelty objection solely on documents D7 and D13, without invoking document D10. In contrast, the patent proprietor argued that document D13 did not disclose the ingestion of the cheese necessary to achieve the use defined in claim 1 of the opposed patent. As a result, the opposition division's decision on novelty was based exclusively on documents D7 and D13.

In the appeal proceedings, the opponent has not demonstrated that the novelty objection based on document D10 was admissibly raised and maintained before the opposition division. Consequently, according to Article 12(4), first sentence, RPBA, the objection raised in the opponent's statement of grounds of appeal constitutes an amendment to its case. Its admittance is therefore subject to the Board's discretion under Article 12(4) and (6) RPBA.

Given the apparent focus of the debate during the oral proceedings before the opposition division on the issue of consumption in relation to document D13, there is no apparent justification for the opponent's failure to argue, at that stage of the proceedings, that the claimed subject-matter lacked novelty over document D10 in view of its explicit disclosure of nutritional compositions comprising calcium depleted MPC intended for consumption.

Furthermore, during the appeal proceedings, the proprietor contested that D10 disclosed the effect of calcium-depleted MPC relevant to the claimed use. Notably, document D10 does not appear prima facie relevant to the issue of novelty, as it primarily addresses the use of calcium-depleted MPC to improve the viscosity of liquid nutritional compositions (see D10, page 5, lines 6-10), without discussing its effect on blood leucine levels or gastric emptying.

The Board has therefore decided not to admit the objection of lack of novelty based on document D10 into the appeal proceedings under Article 12(4) and (6) RPBA.

4. Inventive step

4.1 Closest prior art

4.1.1 Document D7 discloses the ingestion of micellar casein and reports an increase in blood leucine concentration and stimulation of muscle protein synthesis (see D7, page 1710, Figure 2D; page 1712, right column).

Document D12 describes the increase in blood leucine levels and muscle protein synthetic response following the intake of whey or caseinate before or immediately after exercise (see D12, page 8, left column).

It was not in dispute that documents D7 and D12 represent suitable starting points in the prior art, taking account of the purpose of the use defined in the claims and the effects of the protein compositions described in these documents.

4.1.2 Document D11 describes an increased rate of gastric emptying and reduced coagulation in the stomach resulting from the combination of coagulating casein with anti-coagulating pea or soy protein (see D11, claim 1 and paragraphs [0003] and [0009]).

It was undisputed that document D11 represented a suitable starting point with respect to the subject-matter of claim 2 of the patent.

4.1.3 In its communication pursuant Article 15(1) RPBA, the Board expressed the preliminary opinion that the difference of the claimed subject-matter with the teaching in documents D10 and D13 concerned in the first place the very purpose of the defined utility relating to an increase in blood leucine concentration and that, in line with the established jurisprudence, documents D10 and D13 did therefore not represent equally suitable starting points as document D7.

No substantive arguments were submitted by the opponent in response to the Boards's preliminary opinion on this issue.

The Board therefore confirms the preliminary opinion that documents D10 and D13 do not represent alternative suitable starting points in the assessment of inventive step.

4.2 Objective technical problem

4.2.1 The difference between the claimed invention and the teaching in documents D7 or D12 resides in the definition of the casein composition which comprises or is in the form of a calcium-depleted milk MPC or MPI instead of caseinate.

The subject-matter of claim 2 differs from the teaching in document D11 in that the defined use involves calcium-depleted MPC or MPI instead of the combination proposed in D11.

4.2.2 As explained in section 2.2 above, the patent demonstrates in Examples 1 and 3 that calcium-depleted MPC induces a significantly faster and higher increase in blood leucine levels compared to standard MPC and calcium caseinate, an effect comparable to the response observed with whey protein. This effect is corroborated by document D14, which shows that calcium depletion disrupts micellar structure, resulting in looser curds and improved gastric breakdown (see D14, page 6842, Abstract), and by documents D15 and D16, which confirm enhanced amino acid availability and gastric emptying from calcium depleted MPC (see D15, page 1512, left column and page 1517,left column; D16, page 4, sections 13 and 14).

The experiments reported in the patent do not provide a direct comparison with the micellar casein described in document D7 or the caseinate of document D12. However, since the patent demonstrates that calcium-depleted MPC performs better than standard MPC, which contains casein in micellar form, the Board considers this improvement to be equally representative of the performance relative to the micellar casein in document D7. Notably, the micellar structure of casein in standard MPC is disrupted when the MPC undergoes partial calcium depletion (see D14, p. 6842, Abstract and right column; and A19, pp. 315-316, section 13.3.6). Furthermore, given the demonstrated comparable performance of calcium-depleted MPC to whey protein, which was known to serve as a faster and more efficient source of leucine than caseinate (see D12, page 7, right column to page 8, left column), the Board is also satisfied that calcium-depleted MPC provides an advantage over caseinate.

4.2.3 Accordingly, starting from documents D7 or D12, the objective technical problem may be formulated as the provision of an improved casein composition that achieves a higher and faster increase in blood leucine concentration and improved digestibility, comparable to whey protein.

Starting from document D11, the objective technical problem may be formulated as the provision of an alternative casein composition for increasing the rate of gastric emptying and improving digestibility.

4.3 Assessment of the solution

Neither document D7 nor document D12 provides any suggestion towards the use of calcium depleted MPC or MPI. Documents D7 and D12 describe the ingestion of micellar casein or caseinate and report postprandial responses but they do not hint at modifying the casein structure by calcium depletion to achieve higher blood leucine levels and faster digestion.

Document D11 proposes combining casein with anti-coagulating proteins to promote gastric emptying, but does not suggest calcium depletion as an alternative approach.

Documents D10 and D13 disclose calcium depleted MPC in the field of food processing. Document D10 describes its use for improving viscosity in liquid nutritional compositions (see D10, page 5, lines 6-10), while document D13 describes its use for preventing nugget formation in cheese manufacture (see D13, page 5, lines 1-12). However, neither document D10 nor document D13 addresses or suggests the physiological effects underlying the formulated objective technical problem.

Document D4 explains that calcium influences micelle aggregation and that acidification can dissolve calcium phosphate, reducing colloidal stability (see D4, pages 153-152). While this represents general knowledge, it does not provide any indication that calcium depletion would result in higher blood leucine levels and faster digestion. Document D9 reports that low calcium MPC forms finer emulsions compared to higher calcium MPC (see D9, Abstract), but this observation relates to emulsion properties, not digestion kinetics or physiological effects. Document D13 reports that with 98% calcium depleted MPC no coagulum was formed until calcium was added (see page 10, lines 25-31); however, even when read with documents D4 and D9, document D13 focused on processing advantages and does not suggest any physiological benefit following ingestion.

The prior art therefore provides no motivation to use calcium-depleted MPC as a solution to the objective technical problem, whether formulated as an improvement starting from D7 or D12, or, for claim 2, as an alternative starting from D11.

4.4 Accordingly, the Board concludes that subject-matter as defined in the claims of the patent as granted involves an inventive step (Articles 100(a), 56 EPC).