G 0006/88 - Plant growth regulating agent / Second non-medical indication - #48

Citation rank: 48
No. of citations: 95

G 6/88 ("Plant growth regulating agent") is one of two related landmark decisions, which looked at the question to which extent an intended purpose stated in a "use claim" must be considered a limiting technical feature of that claim. This is clearly an important legal question. The present decision's twin (G 2/88, "Friction reducing additive") ranks 3rd(!) in the list of the EPO's most-cited Boards of Appeals decisions of all times.

In the underlying appeal case, claim 1 was directed to the "use of pyrimidine butanol derivatives of the formula X to regulate plant growth." The prior art (D1) disclosed the use pyrimidine butanol derivatives of formula X to control fungi on plants. Both effects (i.e., regulation of plant growth and control of fungi) occurred concurrently, whenever X was applied to plants. However, the plant-growth-regulating effect previously was previously unnoticed. The question then arose whether under such circumstances the stated purpose of claim 1 (regulate plant growth) could establish novelty over the known use of the same compound, despite the fact that the now claimed effect (regulation of plant growth) had in fact previously occurred when the pyrimidine butanol derivatives of formula X were used to control fungi on plants according to D1. In other words, the "technical means" to achieve the two technical effects (regulation of plant growth and fungi control) were the same.

The Board in the underlying appeal case therefore referred the following question of law to the Enlarged Board of Appeal:

"Is a claim to the use of a chemical compound or class of compounds for a particular non-medical purpose novel within the meaning of Article 54 EPC, having regard to prior art which discloses the use of that compound (class of compounds) for a different non-medical purpose, if the two teachings are carried out by identical technical means and the only novel feature in the claim is the use itself?"

The Enlarged Board approached the question in a general manner by investigating how patent claims were traditionally interpreted in the contracting states to the EPC. They observed that different "schools" seemed to exist. In some contries (in particular Germany) the patent claims were broadly interpreted and the protection conferred by it depended more upon what was perceived to be the inventor's contribution to the art, rather than strictly following the wording of the claims. In other countries, in particular in the United Kingdom, the exact wording of the claims was regarded crucial to determine the scope of protection. The EPC sought to minimise the effect of the different traditional approaches to claim interpretation by Art. 69(1) and the corresponding "Protocol on the Interpretation of Article 69 EPC". The Protocol essentially states that the proper way of interpreting claims under the EPC lies between the extremes traditionally practised in Germany and the UK.

With respect to use claims (e.g., of the form:"use of a compound X for a particular purpose"), the Enlarged Board stated that: 

"The recognition or discovery of a previously unknown property of a known compound, such property providing a new technical effect, can clearly involve a valuable and inventive contribution to the art." 

Hence, they were of the opinion that the possibility of protecting inventions covered by use claims was generally regarded desirable.

The Enlarged Board also noted that the issue of "use claims" had already been dealt with in G 1/83 - G 7/83. These decisions were all concerned with the patentability of a further medical use of a compound where a first medical use is already known. The Enlarged Board in G 6/88 pointed out that G 1/83 - G 7/83 had to deal with an additional complication, namely the exclusion of therapeutic methods from patentability. However, the Enlarged Board endorsed the general view taken in G 5/83 that a second non-medical new and non-obvious use of a product is clearly patentable (G 6/88, point 4 of the reasons).

Regarding the interpretation of use claims, the Enlarged Board stated:

"In relation to a claim whose wording clearly defines a new use of a known compound, depending upon its particular wording in the context of the remainder of the patent, the proper interpretation of the claim will normally be such that the attaining of a new technical effect which underlies the new use is a technical feature of the claimed invention." (point 7 of the reasons)

This would be the correct way of interpreting use claims, taking Art. 69(1) EPC and the Protocol on its interpretation into account. Since use claims are to be interpreted such that the desired technical effect is a functional feature of the claim, the stated technical effect can establish novelty over prior art, which does not mention that particular technical effect. An effect which was not noticed or described in a prior art document cannot be regarded as having been "made availlable" by publication of such a document in the sense of Art. 54(2) EPC.

The Enlarged Board also commented on difficulties in infringement proceedings arising from the fact that a potential infringer practising a known use of a compound (e.g., use of compound X to control fungi on plants) could be found infringing a later patent directed to the use of that compound to regulate plant growth. The Enlarged Board, however, found that this could be solved by so-called "vested rights", based on the prior use by the potential infringer. In any event the same problems resulted from allowing patenting the second medical use G 1/83 - G 7/83.

In summary, G 6/88 found that a claim to the use of a compound for a particular purpose, where the purpose relies on a technical effect described in the patent, includes that technical effect as a limiting functional feature. The claim is thus new over prior art disclosing other uses of the same compound, even if the technical means for carrying out the use are identical, as long as the particular technical effect underlying the invention is not disclosed in the prior art.

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Headword:

A claim to the use of a known compound for a particular purpose, which is based on a technical effect which is described in the patent, should be interpreted as including that technical effect as a functional technical feature, and is accordingly not open to objection under Article 54(1) EPC provided that such technical feature has not previously been made available to the public.

The full text of the decision can be found here.