Thursday 14 January 2010

T 1511/07 – Dangerous Liaisons


The case law of the Boards of appeal has been holding for a long time that “the disclosure of a quantitative range of values (e.g. for concentrations or temperatures) together with an included preferred narrower range also directly discloses the two possible part-ranges lying within the overall range on either side of the preferred narrower range. A simple combination of the preferred narrower range and one of the part-ranges is also unequivocally derivable and is supported by the disclosure”. (T 2/81, headnote 2). The present decision adds an intriguing complement to this position.

The patent under consideration concerns a calcium complex. The description of the application as filed contains the following disclosure, immediately after the reference to the embodiments claimed in product claims 1 to 6:


There were no corresponding product claims in the application as filed. After several amendments, the application was finally rejected as contrary to A 123(2).

Claim 1 according to the main request filed before the Board read:

1. A metastable calcium complex formed by the interaction of calcium hydroxide with a mixture of lactic and citric acids, wherein:
− the weight ratio of the citric to lactic acid is from 1:2 to 2:1 and
− the weight ratio of the citric and lactic acids to calcium hydroxide is from 1:1 to 5:1.

And the auxiliary request read:

1. A metastable calcium complex formed by the interaction of calcium hydroxide with a mixture of lactic and citric acids, wherein:
− the weight ratio of the citric to lactic acid is from 1:2 to 2:1 and
− the weight ratio of the citric and lactic acids to calcium hydroxide is from 2.5:1 to 5:1.

The Board reasons as follows:

According to Claim 1 the weight ratio of the citric and lactic acids to calcium hydroxide is from 1:1 to 5:1. This ratio defines a new sub-range which emerges from a combination of the lower value of the broadest range of from 1:1 to 10:1 with the upper value of the especially preferred range of from 2.5:1 to 5:1 as disclosed in the last two lines at page 3 of the application as filed (represented by the WO-publication). This range was combined with the especially preferred range of 1:2 to 2:1 for the weight ratio of citric to lactic acid disclosed at page 3, lines 30/31 of the WO-publication.

Although the selection of explicitly disclosed borderline values defining several (sub)ranges, in order to form a new (narrower) sub range, is not contestable under A 123(2) when the ranges belong to the same list, the combination of an individual range from this list with another individual range emerging from a second list of ranges and relating to a different feature is not considered to be disclosed in the application as filed, unless there is a clear pointer to such a combination.

There is, however, no indication in the WO-publication which unambiguously points to the combination of the weight ratio of 1:1 to 5:1 for the citric and lactic acids to the alkaline calcium source with the weight ratio of 1:2 to 2:1 for the citric to lactic acid. The amendment to Claim 1 is therefore an inadmissible combination from two lists and contravenes A 123(2). [2.1] 

However the auxiliary request is acceptable to the Board:

[…] Both ranges are characterised as especially preferred at page 3, lines 30 to 35 of the WO-publication. In the absence of any information in the application which the skilled person would consider - in view of its impact on the claimed invention - to cast doubt on their combination, identifying the ranges in the two lists as “especially preferred” is, in the Board’s judgment, a clear indication for the intended parallel convergence of the ranges of the two lists; the combination of these two especially preferred ranges therefore satisfies the requirements of A 123(2). [2.2] 

I have to admit that I find the logic of the Board puzzling. If the (disputable) reasoning of T 2/81 is accepted, there appears to be no reason not to allow a combination of the ‘new’ domain with other features.

For some time I have been thinking that the finding of the Board had its origin in the fact that the preferred embodiments contained in the description were not said to be combinable, but the acceptance of the auxiliary request by the Board shows that this cannot be the explanation.

Given this weird application of A 123(2), applicants should think twice before taking advantage of T 2/81. There are unexpected hidden traps.

NB: This decision has already been discussed here (in French).

To read the whole decision, click here.

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