CASELAW-EPO - reviews of EPO Boards of Appeal decisions

T 1886/19 – Lack of sufficiency – How to get from a starting compound to the claimed compound

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The patent concerns the use of dyes in laundry compositions, in particular a laundry composition comprising alkoxylated bis azo-dyes.

Brief outline of the case

The proprietor appealed the decision of the OD to revoke the patent for lack of sufficiency.

The OD concluded that a “process for preparation of the bis-azo dyes falling in the scope of claim 1 has not been disclosed in a manner sufficiently clear and complete that it can be carried out by the skilled person in the art”.

The revocation was confirmed by the board.

The opponent’s position

In response to the OD’s preliminary opinion in the annex to the summons, the opponent raised doubts with respect to sufficiency of disclosure, and filed a document (D11) supporting these submissions.

More specifically, the opponent submitted that the patent did not contain any disclosure regarding the preparation of the bis-azo dye of claim 1 as granted. This lack of information on how the bis-azo dye could be prepared thus needed to be supplied by common general knowledge.

However, the common general knowledge did not provide the skilled person with any information that would allow the claimed compound to be prepared. The opponent concluded that it was unable to obtain the bis-azo dye of claim 1 as granted. D11 includes an experiment similar to the process disclosed in example 1 of D6= US 4,912,203.

The opponent further argued that there were no examples in the patent/application as filed and no common general knowledge which taught the skilled person how to prepare the bis-azo dye referred to in claim 1 of the MR=as granted.

The proprietor’s position

The proprietor relied on D6 to show that the bis-azo dye of claim 1 as granted could be obtained as shown by example 1 of D6.

The proprietor submitted that the OD’s preliminary opinion in the annex to the summons had been positive regarding sufficiency of disclosure. It was not until the OP that the OP had concluded that the requirements of sufficiency of disclosure were not met.

The proprietor submitted that compound BA1 was a product available from a manufacturer, namely Colour Synthesis Solutions Ltd. The skilled person could have purchased compound BA1 in order to prepare the claimed compositions. The claimed invention was thus sufficiently disclosed.

The proprietor submitted that D6 provided the required information that the skilled person would have followed when preparing compound BA1. The skilled person would have used the mono-azo dye disclosed in example 1 of D6 as a starting material and would have prepared compound BA1 by carrying out an ortho-coupling reaction of a diazonium salt compound.

The board’s position

The board disagreed with the proprietor. An objection of lack of sufficiency of disclosure regarding the process for preparing the bis-azo dyes defined in claim 1 as granted had been raised in the notice of opposition. The board noted that the OD concluded in its decision that D6 in combination with the common general knowledge represented by further documents did not disclose the process for preparing the bis-azo dye of claim 1 as granted in a manner sufficiently clear and complete. The decision was thus based on submissions made by the parties before the OP, not during them.

For the board, the application as filed does not disclose any synthesis for compound BA1, which is a bis-azo dye according to claim 1 of the main request. Nor does the application as filed include any reference to how compound BA1 can be prepared or supplied.

As far as the compound BA1 is concerned, the board also disagreed with the proprietor. First, as submitted by the opponent, the application as filed does not identify compound BA1 as a product available from a specific manufacturer. The manufacturer referred to by the appellant, i.e. Colour Synthesis Solutions Ltd., was not identified in the application as filed either. Lastly, it has not been established that BA1 was a commercial product that the skilled person could have purchased.

For the board, there is no indication in the application as filed to start from the very specific compound of example 1 of D6 (the mono-azo aniline compound) in order to synthesise compound BA1. The mere reference to D2=WO 2008/087497 on page 1 of the application as filed would not have guided the skilled person to example 1 of D6. For that reason alone, the appellant’s submission based on D6 must fail.

There is no common general knowledge available on file to show that an ortho-coupling reaction by diazotisation can be performed on the mono-azo aniline compound of example 1 of D6.

Even if it were accepted, purely for the sake of argument, that the skilled person aiming to produce compound BA1 would have consulted D6, this document in combination with the common general knowledge does not provide, the information required for preparing compound BA1, i.e. the information that diazotisation could indeed take place at the ortho-position of the mono-azo aniline compound disclosed in D6 so as to provide compound BA1.


That the opinion of a deciding body of the EPO expressed in an annex to summons is purely provisional, should be amply known by now. Even if the discussions during the OP lead to a change of opinion, the right to be heard will be respected, as long as the affected party is allowed to react appropriately.

The case is interesting in that the lack of sufficiency started with the lack of knowledge as how to synthesise the compound BA1. It was not apparent that when starting with example 1 of D6, it could be arrived at the claimed compund BA1. In the absence of common general knowledge, to compensate the lack of knowledge, the fate of the patent was settled.

Even if the compound BA1 could have been purchased at a producer, it would all depend on how this product was marketed. If it was marketed in a way that its composition was indicated or could be easily retrieved, it could have been accepted a source. Marketed without any indication of its composition, or under a trademark,it would not have been able to take those indications to overcome the objection of lack of sufficiency. For trademarks, see Guidelines F-IV, 8.

The present situation is illustrated in Guidelines G-IV, 2. The present application/patent being not enabling does not belong to the prior art under Art 54(2).

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