T 0418/17 (Therapeutic Oral Composition / COLGATE-PALMOLIVE) 04-06-2020

Summary of Facts and Submissions

I. European patent 2585025 (hereinafter "the patent") was granted on the basis of 15 claims. Claim 1 of the patent as granted read as follows:

"An oral care composition comprising at least one arginine compound in free or salt form, at least one mucoadhesive polymer, and at least one component selected from the group consisting of pyrophosphate compounds, zinc salts, potassium salts, strontium salts, and mixtures thereof, wherein the arginine compound is present in D or L form, or as a salt with lauroyl sulfuric acid, and wherein the arginine compound is present in an amount within the range of from 0.6% to 1% by weight."

II. An opposition was filed against the patent on the grounds that its subject-matter was excluded from patentability by Article 53(c) EPC, it lacked novelty and inventive step, it was not sufficiently disclosed and it extended beyond the content of the application as filed.

III. The opposition division took the interlocutory decision that, on the basis of the main request with claims filed by letter dated 14 September 2016, the patent met the requirements of the EPC.

IV. The decision of the opposition division cited among others the following documents:

D1: US 2009/0202454 A1

D2: WO 2009/100268 A2

V. In particular, the opposition division decided that:

(a) Paragraph [0028] in connection with paragraph [0024] provided a direct an unambiguous basis for the combination of features of claim 1. The main request thus met the requirements of Article 123(2) EPC.

(b) The subject-matter of claims 1 and 9 was considered sufficiently disclosed, especially in view of the examples as regards claim 9.

(c) D2 was seen as the closest prior art. D2 disclosed in Table I a dentifrice with 5% arginine, a mucoadhesive and a potassium salt. The composition according to claim 1 differed in that arginine was present in the range 0.6 to 1%. In the absence of any effect related to this difference, the problem was regarded as the provision of an alternative dentifrice composition for reducing sensitivity of the teeth. The solution was not suggested in D2, and the main request was considered to be inventive.

VI. The opponent (appellant) lodged an appeal against the above decision of the opposition division. With its statement setting out the grounds of appeal, the appellant submitted the following documents:

D4: Markowitz K. "The Original Desensitizers: Strontium and Potassium Salts" J Clin Dent 2009;20(5):145-51.

D5: Schiff T. et al. "Efficacy of a Dentifrice Containing Potassium Nitrate, Soluble Pyrophosphate, PVM/MA Copolymer, and Sodium Fluoride on Dentinal Hypersensitivity: A Twelve-Week Clinical Study" J Clin Dent 1994;5 Spec No:87-92.

D6: Singh "Pro-Argin: A Breakthrough Technology for Dentin Hypersensitivity Treatment" October December 2013, Vol 1

D7: "ProClude is First Prophylaxis Paste to Significantly Reduce or Eliminate Sensitive Teeth in 28 Day Study" March 19, 2003

D8: "Understanding Dental Caries" Edited by Springer, 2016, page 188.

VII. By letter dated 31 August 2017, the patent proprietor (respondent) defended its case on the basis on the main request upheld by the opposition division, auxiliary requests 1-4 filed with letter dated 14 September 2016 and auxiliary requests 5-9 filed with said letter of 31 August 2017.

Claim 1 of the main request was identical with claim 1 as granted (see I. above).

Claims 1, 7 and 8 of auxiliary request 1 respectively read as follows:

"1. An oral care composition comprising at least one arginine compound in free or salt form, at least one mucoadhesive polymer, and at least one component selected from the group consisting of pyrophosphate compounds, zinc salts, potassium salts, strontium salts, and mixtures thereof, wherein the arginine compound is present in D or L form, or as a salt with lauroyl sulfuric acid,

wherein the arginine compound is present in an amount within the range of from 0.6% to 1% by weight,

and wherein the composition comprises a pyrophosphate selected from the group consisting of disodium dihydrogen pyrophosphate (Na2H2P2O7), tetrasodium pyrophosphate (Na4P2O7), tetrapotassium pyrophosphate (K4P2O7), and mixtures thereof."

"7. The composition as claimed in claim 1, wherein the composition has a flow reduction above 50%, when measured using a hydraulic conductance test."

"8. An oral care composition according to claim 1, for use in a method of reducing hypersensitivity of the teeth; said method comprising applying said oral care composition to the oral cavity."

VIII. The Board summoned the parties to oral proceedings.

In a communication pursuant to Article 15(1) RPBA, the Board expressed inter alia the preliminary opinion that the subject-matter of the main request did not involve an inventive step, whereas auxiliary request 1 appeared allowable.

IX. By letter dated 21 May 2020, the respondent withdrew its request for oral proceedings and cancelled its main request on the condition that the patent be maintained on the basis of auxiliary request 1. In the foregoing, despite the fact that the respondent thus made auxiliary request 1 its highest ranking request, this auxiliary request 1 is still called "auxiliary request 1" for sake of consistency.

The appellant had withdrawn its request for oral proceedings by letter dated 26 February 2019.

The oral proceedings were cancelled.

X. The appellant's written arguments, as far as relevant to the present decision, can be summarised as follows:

(a) D4-D8 were relevant in rebutting the appealed decision related to the inventive step. D4 and D5 showed that the agents comprised in the claimed compositions were known to be effective in teeth hypersensitivity. D6 and D7 showed that the skilled person reading D2 was aware of the role of arginine in tubular occlusion and in the treatment of dentinal hypersensitivity. D8 showed that the amount of active ingredients required in a toothpaste was higher than the amount of active ingredients required in a mouthwash. Hence D4-D8 should be admitted into the procedure.

(b) The appealed interlocutory decision was based on the main request and did not relate to auxiliary requests 1-9. In order to have a decision on these auxiliary requests both in the first and in the second instance, the case should be remitted to the opposition division for discussion on auxiliary requests 1-9.

(c) Auxiliary request 1 did not meet the requirements of Article 123(2) EPC. The subject-matter of claim 1 resulted from the selections of items from two lists, namely the range of 0.6-1 wt% for the amount of arginine from the list of alternatives of paragraph [0028], and the claimed arginine type from the list of paragraphs [0024]-[0027]. Additionally, the specific combinations, in claim 1 of auxiliary request 1, of the specific four pyrophosphates plus a zinc salt, or said pyrophosphates plus a potassium salt, or said pyrophosphates and strontium salt, were not disclosed clearly and unambiguously in an individualized form.

(d) The subject-matter of claims 7 and 8 of auxiliary request 1 was not sufficiently disclosed. With respect to claim 8, it had not been credibly shown that the claimed effect was obtained by each of the claimed compositions, in particular by the claimed toothpastes comprising the low amount of 0.6-1 wt% of arginine, because a toothpaste required higher amounts of active ingredients than a mouthwash to be effective due to the dilution upon use. Regarding claim 7, for the same reasons, it was not credible that toothpastes having the claimed amount of arginine would have a flow reduction greater than 50%.

(e) The subject-matter of auxiliary request 1 did not involve an inventive step

D2 represented the closest prior art. The distinguishing features over D2 were 1) the claimed amount of arginine and 2) the presence of pyrophosphates. With regard to the pyrophosphates, the effect derivable from the comparison of examples F and VII of the patent was a mere additive effect due to the addition of pyrophosphate to the arginine/mucoadhesive polymer system of D2: Composition VII (comprising arginine, a mucoadhesive polymer and pyrophosphate) provided a flow reduction which was about the sum of the flow reductions of Compositions F (comprising arginine and a mucoadhesive polymer) and G (comprising a mucoadhesive polymer and pyrophosphate).

Hence, the problem solved could be seen as the provision of an alternative or at most additive composition in the treatment of dentinal hypersensitivity.

The solution was obvious, and the additive effect was expected, because pyrophosphates were known from D5 to treat dentinal hypersensitivity. D5 taught a dentifrice comprising soluble pyrophosphates in combination with PVM/MA, potassium nitrate and sodium fluoride, i.e. in combination with the same components of the opposed patent, of D2 and D5, and effective in the treatment of dentinal hypersensitivity. Therefore, the skilled person starting from D2, would have been motivated by D5 to add pyrophosphates to the composition of D2 in order obtain an additive effect in the treatment of dentinal hypersensitivity. The effect on tubular occlusion was the mechanism of action and was not relevant for the assessment of inventive step. Lastly, in light of D1 (see page 8 paragraph [0068], page 11, Formulae IV, V and VII) the skilled person would have readily recognized that the soluble pyrophosphates of D5 were the specific four pyrophosphates claimed in claim 1 of auxiliary request 1.

XI. The respondent's written arguments, as far as relevant to the present decision, can be summarised as follows:

(a) D4-D8 were not prima facie relevant. Moreover, D4-D8 had not been filed in response to any change in the facts of the case and they could have been produced at a much earlier stage of the opposition proceedings. As such, they were not to be admitted into the proceedings.

(b) For the purposes of Article 123(2) EPC, support for claim 1 of auxiliary request 1 could be found in claim 2 or paragraph [0024] of the application as filed, in combination with paragraph [0028] where the recited amount of arginine of 0.6-1 wt% was indicated to be a preferred amount, and claim 8 or paragraph [0036] indicating that the recited pyrophosphate salts were preferred species.

(c) Regarding sufficiency of disclosure for claims 7 and 8, the examples of the patent showed mouthwash compositions comprising 0.8 wt% arginine, and having a percentage flow reduction of greater than 50%, which reflected their ability to occlude dentinal tubules and therefore, to reduce hypersensitivity. Consequently a presumption existed that the criteria of sufficiency of disclosure were met. The appellant had failed to rebut this presumption by demonstrating serious doubts substantiated by verifiable facts. The appellant had not provided any appropriate evidence to demonstrate that a toothpaste composition comprising a mucoadhesive polymer, a pyrophosphate and arginine in an amount of 0.6 to 1 wt.% in toothpaste would not be suitable for reducing dentinal hypersensitivity. Additionally, claim 8 required a reduction in hypersensitivity without any limitation on the extent of reduction. Thus, a composition was to be regarded as being suitable for the claimed use, even it provided a small reduction in dentinal hypersensitivity.

(d) As to inventive step, starting from the closest prior art D2 (see the composition of Table 1), the differentiating feature of claim 1 of auxiliary request 1 was the requirement for a lower concentration of arginine of 0.6-1 wt% and the presence of a pyrophosphate selected from the group consisting of disodium dihydrogen pyrophosphate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, and mixtures thereof.

The patent demonstrated that the provision of a pyrophosphate compound imparted an unexpected improvement in dentinal tubule occlusion (see Tables 3 and 4, composition F vs compositions VII and VIII). Therefore, in light of D2, the objective technical problem was provision of a composition which provided improved dentinal tubule occlusion.

There was no hint or suggestion in D2 that incorporating pyrophosphate compounds into a composition comprising arginine and a mucoadhesive polymer would result in an improvement in dentinal tubule occlusion. D2 did not mention dentinal tubule occlusion, and attributed an anticalculus function to pyrophosphate compounds.

XII. The appellant requests that the decision under appeal be set aside and that the patent be revoked in its entirety.

The appellant further requests that, should the respondent's main request be considered non patentable, the case be remitted to the opposition division for further discussion on auxiliary requests 1-9.

XIII. The respondent requests that the patent be maintained in amended form on the basis of auxiliary request 1 filed with letter dated 14 September 2016, in which case the main request is cancelled. Alternatively, the respondent requests that the patent be maintained in amended form on the basis of the main request as upheld by the opposition division, or one of auxiliary requests 2-4 filed with letter dated 14 September 2016 or one of the auxiliary requests 5-9 filed with letter dated 31 August 2017.

The respondent further requests that none of D4-D8 be admitted into the proceedings.