T 0268/89 (Magnetic plaster) of 6.2.1992

Summary of Facts and Submissions

I. European patent No. 0 076 354 was granted on 27 August 1986 on the basis of European patent application No. 82 100 942.0 filed on 10 February 1982.

II. The patent was opposed on the grounds set out in Article 100(a) and (b) EPC, and the opponents requested that it be revoked in its entirety, citing the following documents in support of their case:

(2) DE-U-6 904 160

(3) DE-U-1 885 256

(4) DE-A-2 914 904

(5) DE-A-3 041 965.

The objection under Article 100(b) EPC was withdrawn in the course of the opposition proceedings. III. By a decision of 24 February 1989, posted on 7 March 1989, the Opposition Division revoked the patent on the grounds that, having regard to the state of the art as disclosed in documents (2) and (5), the subject-matter of independent Claims 1 and 10 did not involve an inventive step.

IV. An appeal was filed against this decision on 7 April 1989 and the appropriate fee was paid at the same time. The statement of grounds for appeal was received on 27 June 1989, and was later supplemented by a letter dated 23 November 1989.

V. In a letter dated 28 January 1992 the respondents withdrew their opposition. They are therefore no longer a party to the proceedings.

VI. At oral proceedings before the Board of Appeal on 6 February 1992, the appellant's professional representative submitted a new set of claims (Claims 1 to 10), together with an amended description:

Independent Claims 1 and 10 read as follows:

"1. A magnetic plaster consisting of a flexible, permanently magnetisable and magnetised plastic sheet (b) which does not cause skin irritation and is attachable to the skin in a self-adhesive manner or by means of a self-adhesive plaster (c) which does not cause skin irritation, characterised in that the plastic sheet (b) has a thickness of 0.2 to 2 mm and is magnetised with alternating polarity, and the positive and negative poles have a distance of 5 mm between each other and exhibit a magnetic flux density of 40 to 200 mT."

"10. Use of flexible, permanently magnetised plastic sheets having a thickness of 0.2 to 5 mm which do not irritate the skin and are magnetised with alternating polarity, and where the positive and negative poles have a distance of 5 mm between each other and exhibit a magnetic flux density of 40 to 200 mT, for the production of self-adhesive magnetic plasters or magnetic plasters which are attachable to the skin by means of a self-adhesive plaster which does not cause skin irritation."

VII. In support of the argument that the subject-matter of the amended claims involved an inventive step, the appellant's representative referred in particular to the results, submitted during the opposition proceedings, of a randomised double-blind trial, conducted in Switzerland, using sheets magnetised in strips with alternating positive and negative polarity, the distance between the poles being 5 mm (i.e. using the so-called 4-1-4 layout, which means that the magnetic strips themselves are 4 mm wide and are separated by gaps of 1 mm). The trial had shown that magnetised sheets of this kind, when attached to the relevant areas of the skin of patients suffering pain, had an analgesic effect significantly greater than that of blank (placebo) sheets.

VIII. The appellant requests that the contested decision be set aside and the patent maintained on the basis of Claims 1 to 10 and the description as submitted during oral proceedings, together with drawings 1 to 3 as per the patent specification.

Reasons for the Decision

1. The appeal is admissible.

2. Amendments

The current Claims 1 to 10 diverge from the granted claims in that the feature 4° to 20° mT has been replaced by the feature 40 to 200 mT. As a correction of an obvious printing error, this amendment is admissible under Rule 88 EPC. The range of 40 to 200 mT quoted on page 5, line 2, corresponds to the original description.

The value of 5 mm for the distance between the positive and negative poles corresponds to the figure given on page 4, lines 29 to 31, of the original description. It limits the scope of protection for the granted Claims 1 and 10, in which the distance between the poles is given as 4 to 10 mm.

The current documents do not therefore contravene Article 123(2) and (3) EPC.

3. Novelty

None of the documents cited in the proceedings discloses a magnetic plaster or the use of specific types of plastic sheeting in manufacturing magnetic plasters incorporating all the features contained in Claims 1 and 10. The subject-matter of Claims 1 and 10 is therefore new.

4. Closest prior art

In the Board's view, the prior art closest to the invention is represented by document (2), disclosing a flexible, permanently magnetisable and magnetised sheet which can be attached to the skin by means of adhesive strips. The sheet is preferably magnetised axially, i.e. at 90 degrees to its surface; the strength of the magnetic field may vary from one point to another. On page 1 of document (2) the possibility is indicated of using stronger permanent magnets, and the flexibility of the magnetised sheet "enhances the therapeutic effect, since the entire active surface adjusts itself better to the contours of the body, and this ensures that the distance between the body and the active therapeutic surface remains constant".

5. Problem and solution

The Board is unable to share the appellant's view, set out on page 2 of his submission of 23 November 1989, that document (2) could not properly be cited as the closest prior art for the purpose of defining the problem of the present invention. According to the appellant this was because it had been sufficiently common knowledge, at the time when the application had been filed, that magnetotherapy had no effect when used as described in document (2).

This later allegation is contradicted by the appellant's statement in the contested patent specification (column 1, line 64, to column 2, line 5) that the magnetic fields described in document (2) were relatively weak and had scarcely any therapeutic effect; indirectly, the appellant had thereby conceded that a certain effect was possible. At all events, the possibility of total inefficacy had not been recognised on the date of priority or filing and cannot be accepted as an argument ex post facto.

Where the inefficacy of a device or process forming part of the prior art is only recognised or alleged after the date of priority or filing, this cannot be cited in formulating the problem. This particularly applies where a problem of the "problem invention" type (cf. T 2/83, "Simethicone Tablet"/RIDER, OJ EPO 1984, 265) is used as an argument to show that an inventive step has taken place. The guiding consideration in assessing inventive step is the knowledge of the skilled person before the date of priority or filing.

The Board is therefore unable to concur with the appellant's view, expounded on pages 3 and 6 of his submission of 26 June 1989 and again at oral proceedings, that the objective problem consists in a completely new conception of a magnetic plaster, the implication being that the plaster is actually effective.

Instead, the technical problem inferable from the state of the art is to be seen as consisting in a substantial improvement, with regard to therapeutic effect, of the magnetic plaster disclosed in document (2).

This problem is solved by the features of Claims 1 and/or 10, the claimed distance of 5 mm between the poles and the magnetic flux density of 40 to 200 mT of the alternating magnetic field being particularly significant because these parameters determine the depth of penetration of the magnetic fields and the therapeutic effect of the invention.

6. Inventive step

6.1 The Board accepts the Opposition Division's reasoning in paragraphs 4.1 to 4.3 of the contested decision. It believes that, given the improved therapeutic effect of therapeutic devices using static magnetic fields as described in document (5), the skilled person treating disorders generally associated with blood circulation and seeking a solution to the problem cited in paragraph 5 above would take into account the teaching set out in that document. The Board therefore regards it as an obvious step to attempt to confer on the magnetised sheet disclosed in document (2) the properties of the magnetic field with alternating polarity described on p. 10 (first paragraph) and depicted in Fig. 11, in view of the considerably enhanced stimulant effect disclosed in the same document.

It is relevant that the important information implicitly contained in document (5) could only become apparent after experimental tests had been conducted. The Board agrees with the Opposition Division's comments on the dimensions constituting the routine parameters for the magnetic flux density, the thickness of the sheet and the distance between the poles. It accepts in particular - given the requirements in document (5), pages 3 and 10, of an interpolar distance in excess of a given value and a magnetic field of maximum strength - that a lower and upper limit for the distance between the poles could be established by routine testing, and that the distance of 4 to 10 mm quoted in the granted Claim 1 can therefore be regarded as obvious, insofar as the general enhancement of the therapeutic effect is concerned.

6.2 The question therefore arises of whether the choice of a specific value of 5 mm for the distance between the poles - as per the current Claims 1 and 10 - can be said to render the subject-matter of these claims inventive.

During the oral proceedings the appellant argued that the magnetic plaster as per the invention, with a distance of 5 mm between the poles, had a statistically significant analgesic effect. He supported this assertion by producing the record and results of a randomised double-blind trial of magnetised sheets with a distance of 5 mm between the poles. The other documents presented in the course of the examination and opposition proceedings also indicate that the magnetised sheet as per the invention was effective, at least in treating pain. In all the tests conducted on the magnetised sheet, the distance between the poles was 5 mm.

Specific effects were therefore produced by using this value for the distance between the poles. Even taking document (5) into account, there was no way of predicting that this value would be critical. The step prompted by document (5) - finding a distance between the two poles which would generally improve the blood circulation - was to be regarded as obvious. Now, an exact value had been found for the modified magnetic sheet which made it possible to treat specific medical conditions.

In the case of unusual therapeutic methods, where reproducibility and efficacy are not generally recognised and are difficult to prove because they depend on a variety of circumstances, exactly defined, successful therapeutic effects can scarcely be regarded as foreseeable, especially if only produced by modified means.

The Board has no reason to doubt the veracity of the appellant's statement or the accuracy of the test results, especially the conclusions of the double-blind trial. The then respondents did not call into question the efficacy of the magnetic plaster as per the invention, either with regard to the distance of 4 to 10 mm claimed in the contested patent or in respect of the distance of 5 mm which was particularly emphasised in the granted patent and is now being claimed; on the contrary, they accepted it on page 5 of their submission of 16 May 1988. Nor have they presented any proof in the shape of comparative tests or other counter-evidence to refute the assertion that the magnetised sheets with alternating polarity as per the invention, with a distance of 5 mm between the poles, produce an optimum analgesic action; i.e. that they have a specific therapeutic effect.

The Board is therefore bound to assume that the distance of 5 mm as per the invention, while selected from an obvious range of possible values, is a particular value which causes the magnetic plasters as per the invention to have a significant analgesic effect in specific cases. This offers sufficient grounds for saying that the invention involves an inventive step. It is possible that the treatment of other medical conditions by similar means would require different values for the distance between the poles.

6.3 The remaining documents (2) to (4) cited in the proceedings did not suggest the specific value of 5 mm for the distance between the poles. Although Figs. 2, 3 and 4 in document (3) show magnetic strips with alternating areas of polarity, they neither disclose a distance of 5 mm between the poles nor do they allow such a distance to be inferred. On the contrary: Fig. 7 implies that the distance between the poles is considerably greater. Documents (2) and (4) do not disclose any magnetised areas with alternating polarity.

6.4 It must therefore be accepted that the subject-matter of Claims 1 and 10 involves an inventive step.

7. Independent Claims 1 and 10 therefore comply with the requirements of Article 52(1) EPC regarding patentability.

Claims 2 to 9 are upheld together with Claim 1, to which they refer.

ORDER

For these reasons it is decided that:

1. The contested decision is set aside.

2. The case is remitted to the department of first instance with instructions to maintain the European patent in amended form on the basis of the documents referred to in section VIII above.