T 826/06 – No Causal Link

The present decision deals with an appeal filed by several opponents after the Opposition Division (OD) had maintained the opposed patent in amended form.

Claim 1 as granted read:

Use of at least one dye, which dye is capable of staining tissue without diffusing through said tissue, for the manufacture of a staining composition for visualizing a lens capsule in an eye during performance of a capsulorhexis.

NB: Capsulorhexis is a technique used to remove the lens capsule during cataract surgery.

Claim 1 of the main request before the Board was identical with the claim as maintained by the OD:

1. Use of at least one dye, which dye is capable of staining tissue without diffusing through said tissue, said dye being represented by the formula (I)

wherein R1 and R2 are the same or different aryl groups, and wherein R3 and R4 are independently chosen from hydrogen, methyl, ethyl, methoxy, amino, hydroxyl and sulfonate

for the manufacture of a staining composition for visualizing a [sic] the anterior lens capsule in an eye during performance of a capsulorhexis.

The OD was of the opinion that the Swiss-type form claim was adequate in view of the fact that the surgical method relating to the capsulorhexis could be considered as a method of treatment of the human or animal body under A 52(4) EPC 1973. As a consequence, the conditions for the legal fiction set out in Enlarged Board of Appeal decision G 5/83 directly applied.

The Board sees things in a different light:

[2.1] Methods for treatment of the human and animal body by surgery are listed among the methods excluded from patentability according to A 52(4) EPC 1973 (A 53(c) EPC 2000). Therefore, the conditions set out in decision G 5/83 for claims directed to further medical indications in methods for treatment by therapy apply in principle to chemical products to be used in methods for treatment by surgery.

Decision G 5/83 institutes the Swiss-type form for claims relating to further medical indications. Thus, the Swiss-type form concerns a legal fiction that allows a specific medical use for a known product to act as a functional feature conferring notional novelty on the use of the product for the manufacture of a medicament which is otherwise known per se.

[2.2] Therefore, the wording in claim 1 of the main request has to be investigated in order to determine whether or not the definitions contained in the claim reflect functional features of the product (in the present case the dye) whose use is addressed.

Formally, claim 1 of the main request is drafted in a Swiss-type form. The claim relates to:

(a) Use of at least one dye ..., said dye represented by formula I (the dye is the chemical product)

(b) for the manufacture of a staining composition (the word “medicament” is not appropriate here since the staining composition may be useful in a method for treatment by surgery, but it is not a medicament stricto sensu)

(c) for visualizing the anterior lens capsule in an eye during performance of a capsulorhexis (emphasis added).

[2.3] Capsulorhexis means the controlled opening by making a continuous circular tear in the anterior lens capsule of an eye. Accordingly, capsulorhexis per se is not a complete method for treatment by surgery, but it may only be a step in other surgical methods. According to the patent in suit, one complete method for treatment by surgery is the surgical procedure for cataract extraction. However, claim 1 of the main request does not specify the surgical procedure for cataract extraction.

Therefore, in the absence of any specification in claim 1 of the main request in relation to the fact that capsulorhexis is a step of a complete method for a defined treatment by surgery, the legal fiction conferred by the Swiss-type form according to G 5/83 does not apply, and the use claimed is only a method for the manufacture of a staining composition which is known per se (see inter alia documents D8 and D7 which disclose staining compositions containing the vital dye trypan blue). Thus, claim 1 of the main request lacks novelty.

[2.4] Moreover, even assuming in favour of the respondent that capsulorhexis is limited to an act of surgery and thus inevitably part of a method for treatment by surgery, a precise scrutiny of the claim's wording also shows that there is no causal link between the staining function of the dye and the method of opening expressed in the claim by the words “during capsulorhexis”.

[2.5] Leaving aside the parties’ dispute whether “visualizing” is merely a mental act performed by the observer (in that case a surgeon), “visualizing” is performed “during capsulorhexis”. It has to be recalled that a technical effect may confer novelty on the use of a known product only if there is a causal link between the product and the “new” technical effect for which the use is claimed (see G 1/07 [5.10.9]). Only if such a functional link is shown novelty may be conferred on the use. In the present case the product for which the use is claimed is a dye, thus the technical effect may be a selective dying. The technical effect cannot, however, be a capsulorhexis which is a mode of opening performed by the surgeon. The mention of capsulorhexis in the claim is made only by way of a circumstantial expression “during capsulorhexis” which remains deprived of any causal link to the dye product. Thus, “visualizing” has to be taken in its broadest sense as a synonym (as its direct result) for staining the anterior lens capsule of the eye (to an extent which is not specified in claim 1 of the main request).

[2.6] Consequently, the establishment of a temporal condition (“during capsulorhexis”) cannot confer novelty on the use claimed by means of providing for a functional feature of the dye, since in the claim the action of staining the anterior lens capsule and the time in which the observer looks at the stained capsule are not causally linked.

[2.7] Therefore, document D8 which discloses staining of an anterior lens capsule in an eye by using trypan blue deprives claim 1 of the main request of novelty (A 52(1) and A 54(2)).

[2.8] Decision G 2/08 has put an end to the Swiss-type format (for applications filed after its publication date plus a certain time limit).

Moreover, in the case underlying the referral G 2/08 the claim mentioned hyperlipidaemia as the ailment treated by medicament therapy. Thus, following the logic in decision G 2/08, dosage regimen might be acknowledged as the feature conferring notional novelty on a purpose-related product claim within the meaning of A 54(5) EPC 2000, since it is a step pertaining by its nature to a therapeutic method concretised by the administration of the medicament containing the product.

[2.9] Moreover, even following the respondent’s argumentation that, in analogy to decision G 2/08, a particular dosage regimen might also confer notional novelty to the use of a known product in a method for treatment by therapy in a Swiss-type form, there are still insurmountable differences with the present case.

A staining composition is not a medicament stricto sensu, and capsulorhexis is not necessarily part of a therapeutic treatment attained by the dye product. Capsulorhexis pertains by its nature to a controlled opening technique of the lens capsule which is not inevitably part of a method for therapy resulting from the use of the product mentioned in the claim. Thus, in contrast to the situation with the dosage regimen in which there is a direct link between the administration of the medicament and the product for which the use is claimed, capsulorhexis is an act of the surgeon independent from the application of the dye as a staining composition to an eye. Accordingly, capsulorhexis is causatively and sequentially disconnected from staining in claim 1 of the main request.

[2.10] Additionally, the fact that document D8 only reports a partial staining of the anterior lens capsule does not help to overcome the lack of novelty of the claimed subject-matter, since the claim does not clearly define the quality or extension of the staining.

[2.11] Consequently, claim 1 of the main request fails for lack of novelty over document D8.

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