Friday, 25 July 2014

T2403/11 - Bound by earlier reasoning and statements in application

This appeal decision relates to a discussion of insufficiency of disclosure in opposition proceedings. In this opposition proceedings, all requests were rejected because it was not well defined how the claimed "viscosity" could be determined. The Board also discusses this subject with reference to previous case law. Furthermore, in the appeal the patent proprietor tried to argue that viscosity was not an important feature of the claim, however, contradictory arguments were provided earlier and statements in the patent application seems to contradict the new line or arguments.

Citations from the decision:

An ill-defined parameter in a claim may lead to insufficiency of disclosure if this parameter is relevant for solving the problem addressed in the patent (T 593/09 followed). If, in such a situation, the patent specification states that the ill-defined parameter is relevant and the patent proprietor initially argued along those lines, then, normally it cannot argue, later on in the proceedings, that this parameter does not matter (points 2.6.1 and 2.6.2 of the Reasons).


The opposition division's position can be summarised as follows:
None of the requests met the requirements of Article 100(b) EPC. It had not been substantiated that there was a particular method in the prior art which had to be used to determine the viscosity. The skilled person was therefore faced with a number of choices as to which procedure to use, choices which influenced the outcome of the measurement. While claim 1 specified which temperature had to be employed, further conditions such as the selection of the viscosimeter, as well as the container used and the sample pre-treatment, had to be selected and there was no unambiguous instruction on these choices. In fact, given that D10 (section 11 "Report") specified that these conditions had to be controlled, the skilled person would infer that these conditions had an appreciable effect on the measurement. It also appeared from D10 that the spindle/speed combination had a major bearing on the outcome of the measurement. This was further demonstrated by the proprietor itself in its letter of 8 August 2011, which showed large differences in the measured viscosity at different spindle speeds. It could therefore only be concluded that it had not been proven that the skilled person knew which method to use, and, within a single method, the number of selections required inevitably led to different results. Reproducing the invention thus required a significant effort which went beyond any normal trial and error. As the viscosity was an essential parameter in practising or reproducing the invention, without proper instruction on this parameter the skilled person was not able to perform the invention.

Reasons for the Decision
2. Sufficiency of disclosure (Article 100(b) EPC)
 2.1 Claim 1 is directed to a composition for coating foodstuffs which comprises a galactomannan, such as guar gum, and 2 to 7 wt% of alginate, and has a viscosity of 80-110 Pas at a temperature of 20°C (for the exact wording of claim 1, see point IV above).
According to the respondent, the viscosity parameter in claim 1 is ambiguous since the patent does not give the method for identifying it, and this ambiguity means that the invention underlying the patent is insufficiently disclosed.

2.2 The present case is similar to the one underlying decision T 593/09 (not published in OJ EPO), in which sufficiency of disclosure had likewise to be decided in relation to a parameter ("LTC temperature") for which the measurement method was not sufficiently defined in the patent. As set out in this decision (catchword and point 4.1.4 of the Reasons), the ambiguity of a parameter in a claim is not, by itself, a reason to deny sufficiency of disclosure. What is decisive for establishing insufficiency within the meaning of Article 83 EPC is whether the parameter, in the specific case, is so ill-defined that the skilled person is not able, on the basis of the disclosure as a whole and using his common general knowledge, to identify without undue burden the technical measures necessary to solve the problem underlying the patent.
As set out in this decision, in order to find out whether this condition for insufficiency of disclosure is met, a four-step approach can be applied. Firstly, the problem to be solved by the invention in the patent is identified (point 2.1 of the Reasons), secondly the relevance of the attacked parameter for solving this problem is determined (point 2.2 of the Reasons), thirdly it is analysed whether the parameter in the claim is indeed ambiguous (points 3.1 to 3.5 of the Reasons) and fourthly, if the parameter is ambiguous, it is determined whether due to this ambiguity and the relevance of the parameter for solving the problem, sufficiency of disclosure has to be denied (points 3.6 and 3.7 of the Reasons). This four-step approach will be applied in the present case as well (points 2.3 to 2.6 below).

2.3 The opposed patent relates to compositions for coating foodstuffs (paragraph [0001]). The objective of the invention underlying the patent is the provision of a coating composition with which a sufficiently robust and stable coating can be formed using the extrusion or co-extrusion techniques that are commonly used in the food industry (paragraph [0013]).

2.4 As set out in paragraph [0004], the rheological properties, and especially the viscosity, of the coating composition play a major role in achieving the objective of the opposed patent. If the viscosity is too low, the composition deliquesces before it can be gelled, so that no cohesive coating can be formed. Too high a viscosity can lead to problems in extrusion and to undesirable ripping of the coating. To achieve this objective, the coating composition must have a viscosity of 80-110 Pas at a temperature of 20°C (claim 1 and paragraph [0029]).
The skilled person who wants to carry out the invention, i.e. to obtain coating compositions with which a sufficiently robust and stable coating can be formed, thus needs to determine the viscosity of the coating composition in order to check whether it is within the required range.

2.5 It needs to be examined, as a next step, whether the viscosity is indeed ambiguous.

2.5.1 In this respect, it was acknowledged by the appellant that the patent does not contain any information as regards the type of measurement device or measurement parameters to determine the viscosity, that there are various measurement methods available to the skilled person and that the measured viscosity values depend on the type of measurement device and, for a given device, on the measurement parameters.

2.5.2 The appellant argued however that the skilled person was nevertheless able to find out which method and parameters to use in order to determine the required viscosity. All that the skilled person needed to do was to calibrate the measurement characteristics on the basis of the examples of the opposed patent. More specifically, the skilled person had simply to prepare the compositions of these examples and then to "tune" the measurement parameters until the viscosity values reported in these examples were obtained. The appellant in this respect referred to D12 and D13, where two independent test institutes had reworked the examples of the patent (D12: examples 1 to 4, D13: examples 1 to 3 and 5) and, by tuning the measurement frequency, had been able to obtain the reported viscosity values. The measurement method thus found could be used to check whether the viscosity of any other given coating composition was as required in claim 1. By doing so, compositions suitable to provide robust and stable coatings could be obtained.
Firstly, however, it is nowhere shown in D12 or D13 that the compositions prepared therein are indeed suitable to prepare robust and stable coatings. In fact, it is explicitly stated by the authors of D12 that "[F]urther work described in the patent concerning the application of the gels to be used as a coating of sausages was not part of the investigations [of D12]".
Secondly, it was necessary in the tests reported in D12 and D13 to experiment with various measurement devices that are typical for university departments specialised in viscosity measurement and only a sophisticated multi-step analysis in the end led to viscosity values that were at least close to those in the examples. Such a calibration could thus only be done by a person specialised in the field of viscosity measurement. The patent is however not directed at an analytical scientist specialised in viscosity measurement but to food technologists (paragraph [0001]: "The invention relates to a composition for coating foodstuffs..."). Hence, the skilled person in the art relevant to the patent would not be able to use the calibration techniques applied in D12 or D13.
Thirdly, in fact a calibration of the viscosity measurement is, as a matter of principle, not possible on the basis of the examples of the patent. Such a calibration presupposes that the measurement parameters are the only variables in the examples that determine the viscosity. As will be shown in the following, this condition is not met:
All examples of the patent use guar gum without specifying the type of guar gum. As evidenced by D14, D15 and D16, different guar gums are available. As shown in D17 (table on last page), the viscosity of the compositions used in the examples depend on the type of guar gum. More specifically, in D17, the viscosities of three mixtures each containing a different guar gum are determined, namely containing (i) alginate and Guar HV (a guar gum having a viscosity of 6500 ctp) (test 1), (ii) alginate and Guar standard (3500 ctp) (test 2) and (iii) alginate and depolymerised Guar (50 ctp) (test 3). The viscosity of these mixtures was 1360 Pas for mixture (i), 497.5 Pas for mixture (ii) and 185.6 Pas for mixture (iii), and thus depends on the type of guar gum used. Consequently, the fact that the authors of D12 and D13 were able to tune the measurement method such that the viscosities reported in the corresponding examples were obtained does not mean that it is this method that is to be used according to the patent. On the contrary, it could equally be a different method, if a different guar gum was used in the examples.
For these reasons, the appellant's argument that the measurement method for the determination of the viscosity can be calibrated and thus identified on the basis of the examples of the patent must fail.

2.5.3 As regards the dependence of the viscosity on the type of guar gum shown in D17, the appellant's expert Mr Knoch argued that he had doubts about the correctness of these values, since no details were given in D17 about how the experiments had been carried out. This submission can however not be taken into account in view of the fact that it was made at the latest possible time during the appeal proceedings, while the report had already been available for two years and furthermore since the doubts raised by the expert were not substantiated. Irrespective of this, even if there were some doubt about the absolute values reported in D17, this test report shows at least qualitatively a dependence of the viscosity on the type of guar gum.

2.5.4 The appellant also argued that the skilled person would use a standard guard gum in the examples of the patent and that this standard guar gum had a viscosity between 3000 and 5000 cps, as evidenced by D14. The skilled person would thus know which type of guar gum to use and therefore would be able to calibrate the viscosity measurement method on the basis of the examples.
The board does not find this argument convincing. First of all, nowhere does the patent indicate that indeed standard guar gum is used in the examples. Secondly, even if, in the appellant's favour, it is assumed that the skilled person reading the examples of the patent would indeed use standard guar gum, it would still not be possible to use the examples to calibrate the viscosity measurement method. More specifically, as acknowledged by the appellant, standard guar gum is available within a viscosity range of 3000 to 5000 cps. Thus, the type of the guar gum would still be a variable in the examples that would affect the viscosity of the resulting coating composition.

2.5.5 Consequently, on the basis of the patent and his common general knowledge, the skilled person is unable to identify the measurement method by which the viscosity values required by claim 1 have to be determined. In view of the fact that the values depend on the type of measurement method and parameters, the skilled person cannot tell whether or not a given composition has a viscosity as required by claim 1. The viscosity in claim 1 is thus ambiguous.

2.6 In view of its ambiguity, the viscosity is not available as a selection criterion to identify suitable coating compositions that solve the problem underlying the opposed patent. The skilled person therefore has to identify suitable compositions by trial and error. Hence, the patent is nothing more than an invitation to perform a research programme.

2.6.1 While the appellant during the oral proceedings initially acknowledged that the viscosity as required by claim 1 was indeed essential to solve the problem underlying the patent, it later on presented a second line of argument starting from the assumption that the viscosity was in fact not relevant. According to this line of argument, all that was needed to carry out the invention was to select the preferred galactomannan, namely guar gum, in the amounts indicated in the description of the patent. For instance, the skilled person simply needed to repeat the examples of the opposed patent and choose a standard guar gum to obtain a suitable coating composition. Hence, in order to carry out the invention the skilled person did not need to know how to determine the viscosity. In fact the viscosity had only been included in claim 1 to determine later on whether a given composition infringed the patent or not.

2.6.2 The board does not find this argument acceptable. The proprietor is not free to choose a particular approach when drafting the patent and when arguing its case, and then to change it later on when it realises that this approach might fail. So if the proprietor (and in the present case appellant) chooses to include a statement when drafting the patent that, in order to solve the problem underlying the patent, the coating composition must have a certain viscosity, then normally it cannot argue, later on in the proceedings, that in fact the viscosity does not matter.
Furthermore, even if one accepts the appellant's argument, the patent does not teach the skilled person how to obtain a suitable coating for any composition different from those of the examples, for instance a composition containing a galactomannan different from guar gum. Since, due to its ambiguity, the viscosity is not available as a selection criterion to identify suitable components and amounts for these different compositions, the conclusion remains valid that the skilled person has to rely on trial and error such that the patent is nothing more than an invitation to perform a research programme.

 2.8 The invention underlying claim 1 is thus insufficiently disclosed.
For these reasons it is decided that:
The appeal is dismissed.

This decision has European Case Law Identifier: ECLI:EP:BA:2014:T240311.20140430.
The whole decision can be found here.
The file wrapper can be found here.

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