How much trial and error can be expected from the skilled person ? A bit but not too much, says the Board. Well, that is the sort of answer one would have expected. Still, the present decision is helpful as it gives an example of what is acceptable and where “too much” begins.
According to A 83 and its counterpart in A 100 b), the requirement of sufficient disclosure means that an invention shall be disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.
The specific requirement of R 42(1)(e) that the description shall describe in detail at least one way of carrying out the invention claimed is, according to established jurisprudence, sufficiently fulfilled only if:
(i) the disclosure allows the invention to be performed in the whole range claimed (T 409/91 [3.5]; T 435/91 [2.2.1]);
(ii) the whole subject-matter as defined in the claims can be carried out by the person skilled in the art, at the filing date of the application, without undue burden (see e.g. decision T 14/83 [6]). [1.1]
In the case at issue, claims 1 of both requests are directed to an amorphous silica characterised by 10 and 11 different parameters, respectively, and the contested patent describes in detail the preparation of two specific amorphous silicas having parameter values falling within the claimed ranges.
The board however observes that the definition “amorphous silica” comprises a host of possible chemical compounds which may or may not satisfy the multiplicity of parameters defined in the claims of the requests at issue and in this context, the question arises whether the patent contains sufficient information about how these parameters are to be reliably achieved so that the person skilled in the art has at his disposal a process which leads him in a direct way to the amorphous silicas claimed. [1.2]
Concerning the preparation of the amorphous silicas disclosed in the patent in suit, there is the information at paragraphs [0022] and [0021] that amorphous silicas presenting good cleaning characteristics without damaging teeth and which are particularly good at preventing stain formation can be obtained through a process comprising […]
The board however notes that the description of the contested patent does not give any details as to how [these] process conditions “for preparing amorphous silicas presenting good cleaning characteristics without damaging teeth and which are particularly good at preventing stain formation” might be modified in order to achieve reliably the parameters of the specific amorphous silicas defined in the claims 1 at issue. [1.3]
Having been questioned on that point at the oral proceedings (OPs), the [patentee] admitted that by carrying out the process according to paragraphs [0022] and [0021] of the contested patent, the skilled practitioner would not necessarily arrive at an amorphous silica falling within the wording of claims 1 of both requests at issue. It however contended that by varying the process conditions described in detail with respect to the two amorphous silicas specifically exemplified in the contested patent, one would arrive at the preparation of amorphous silicas falling within the ambit of the claims 1 of both requests at issue. [1.4]
The board does not contest that by carrying out slight variations on the process conditions described in detail in Examples 1 and 2 of the patent in suit, it might well be possible for the skilled practitioner to arrive at the preparation of some amorphous silicas falling within the ambit of the claims at issue. [1.5]
However, bearing in mind that the contested patent had been revoked in particular because of the absence of details as regards the stirring speed used during the preparation of the silica claimed, the discussion at the OPs focused on this crucial point whereby the [patentee] confirmed that stirring was an important feature and it pointed in this respect to paragraph [0049] of the patent in suit, reading:
“Mixing is an important feature in the reaction of silicate and sulphuric acid. Consequently fixed specifications, as listed in Chemineer Inc. Chem. Eng. 26 April 1976 pages 102-110, have been used to design the baffled, heated stirred reaction vessel. Whilst the turbine design is optional to the mixing geometry, a 6— bladed 30° pitched bladed unit has been chosen for the experiments in order to ensure maximum mixing effectiveness with minimum shear.” [1.6]
The [patentee] argued that the skilled person reading said paragraph would use the above suggested turbine design and owing to the teaching that “minimum shear” with “maximum mixing effectiveness” was to be ensured, he would find the information necessary to ensure the “minimum shear” in the document cited in the above passage, i.e. D10. It quoted in this respect Table 1 and Figure 2 of D10 […]
Relying on the content of document D10, the board does not accept this argument because neither Table 1, nor Figure 2, nor the four excerpts submitted as D10 address the preparation of an amorphous silica, let alone the preparation of a silica having the properties presently claimed. Furthermore, neither Table 1, nor Figure 2, nor the remaining parts of D10 appear to provide the information necessary to ensure the “minimum shear” with “maximum mixing effectiveness” referred in the paragraph [0049] of the patent in suit. The [patentee] was invited to comment on this issue at the OPs but was in particular not able to explain how the skilled person using the information found in document D10 should operate to arrive without undue experimentation at the product claimed.
Since the stirring conditions are missing as regards the preparation of the two examples, there are no concrete data on which the skilled person could rely. This means that as regards the preparation of amorphous silicas claimed other than those specifically exemplified in the patent in suit, the stirring conditions have in any case to be discovered by trial and error. [1.7]
The [patentee] argued in this respect that the determination of the optimal stirring speed in the preparation of the silica claimed would be arrived at without undue burden simply by varying the stirring speed during the reaction of silicate with sulphuric acid while reworking the two examples of the patent specification.
The board can accept that such a trial and error experimentation might in the present case not be considered as undue burden as far as the silicas illustrated in the examples of the contested patent are concerned. However, this reasoning which can be accepted only for the two examples, does not hold good for the other claimed but non-exemplified amorphous silicas and in the absence of any specific recipe concerning the preparation of such silicas, the problems concerning the stirring speed still remain for silicas claimed over the whole range. [1.8]
The skilled person is thus confronted with the uncontested fact that he has a lot of process variables affecting the claimed parameters, but once he has encountered failure in one parameter value, there is no clear guidance enabling him to adjust the multitude of process steps in order to arrive with certitude at silicas meeting the parameter requirements defined in claim 1 of both requests at issue.
Even though a reasonable amount of trial and error is permissible when it comes to assessing sufficiency of disclosure, there must still be adequate instructions in the specification, or on the basis of common general knowledge, leading the skilled person necessarily and directly towards success, through evaluation of initial failures. This is not the case here, since the preparation of the amorphous silicas claimed is made dependent on the adjustment of different process parameters for which no guidance is given in the patent in suit, so that the broad definition of an amorphous silica as presently claimed is no more than an invitation to perform a research program in order to find a suitable way of preparing the amorphous silicas over the whole area claimed. [1.9]
It follows from the above, that the principle underlying A 83 that the skilled person should be given sufficient guidance for performing the invention without undue burden over the whole range claimed is thus not fulfilled and therefore, the subject-matter of claims 1 of both requests at issue is found not to meet the requirements of A 100 (b). [1.10]
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