A recent decision by the EPO Boards of Appeal(T1218/14)highlights the pitfalls of using undisclosed disclaimers in patent claims. Here, Senior Patent Attorney Clair Curran details why these are used and what you should watch out for.

Ordering a coffee — disclaimers explained

The choices you’re faced with when ordering a coffee these days can be overwhelming. But whether you’re a fan of the Flat White, Decaf Latté or Skim Venti Caramel Macchiato with Extra Whip, it’s common practice to use phrases like:

A flat white with a shot of hazelnut syrup, to go


A grande Americano without milk, please”.

The first order recites the components of the drink in a positive manner. The barista knows to include a shot of hazelnut syrup.

In the second order, rather than saying “A black grande Americano”, the phrase disclaims specific components. The customer wants milk to be absent from in the drink.

This type of positive or negative recitation of features is standard (yet rarely thought about) in everyday life.

When is negative language allowed?

In certain prescribed circumstances, the European Patent Office (EPO) will allow the use of such ‘negative’ language within a claim. For example, a technical feature can be disclaimed (negatively recited) within a patent claim.

In some cases, the negative language is written into the original application during the drafting process, as a proviso.

An example would be: The application as filed explicitly discloses a carbonated beverage excluding a colour additive.

There are two other types of disclaimer based on language that weren’t included in the application as originally filed.

Disclosed disclaimer

A 'disclosed disclaimer' is where the subject-matter excluded from the scope of the claim by amendment was originally described in the application as a possible embodiment of the invention. That is, a feature that was originally disclosed as a positive feature of the invention is now explicitly disclaimed, as a negative feature.

An example would be: The application as filed disclosed a carbonated beverage may include a colour additive. A claim might be amended to recite “a carbonated beverage excluding a colour additive”.

Undisclosed disclaimer

An 'undisclosed disclaimer' is where neither the disclaimer nor the subject-matter excluded by it was described in the application as filed.

The EPO assesses the allowability of these different types of disclaimer using different tests. The decisions of the Enlarged Board of Appeal in G1/03 and G1/16 provided the criteria for the allowability of an undisclosed disclaimer, which includes the allowability of an undisclosed disclaimer delimiting a claim against an accidental anticipation.

An anticipation is ‘accidental’ if, from a technical point of view, it’s so unrelated and remote that a person skilled in the art would never have taken it into consideration when making or working on the invention.

However, this approach may only be partly successful — here’s why.

Background on the case (EP1812548) — Preparing gluten-reduced beverages

Prolamin- (gluten-) containing cereal species are used to make beverages, like beer. Such beverages aren’t suitable for consumption by celiacs. N-Zyme BioTec GmbH developed a process of preparing prolamin-reduced beverages and subsequently filed a patent application.

Claim 1 related to a process of preparing a beverage, a beverage base, a beverage concentrate or a beverage additive that includes: (a) contacting the beverage or a precursor of the beverage with cross-linking enzymes to obtain modified prolamin and (b) removing the modified prolamin.

The granted patent (then owned by Döhler GmbH) was opposed by DuPont Nutrition Biosciences ApS.

The opposition (WO02/15713) — Processing wheat flour

Novozymes had developed a method of separating a gluten fraction from wheat flour using a transglutaminase enzyme and filed for patent protection before the filing date of EP1812548.

When considering the validity of EP1812548, the Opposition Division found the teachings in this document to be prejudicial to the novelty of claim 1. One reason for this was that example 2 of WO02/15713 taught a method of making a dough by mixing wheat flour, water and a transglutaminase enzyme. The dough is then homogenised and centrifuged, and the starch-containing pellet fraction (essentially pure of gluten) is liquified and saccharified to give a syrup.

The Opposition Division considered that a skilled person in the art would consider both the starch fraction and the syrup as a (potential) beverage base, concentrate or additive.

EP1812548 survived opposition proceedings in an amended form, with the reference to “a beverage base, a beverage concentrate or a beverage additive” being removed from claim 1.

Disclaiming the method disclosed in WO02/15713

During Appeal proceedings, Döhler GmbH argued that the field of beverages and flours are so unrelated and remote that a person skilled in the art would never have taken the method of processing wheat flour into consideration when developing a process of making gluten-free beverages. Surely then, this document qualifies as an ‘accidental anticipation’.

During the Appeal Proceedings an auxiliary request was submitted that included an undisclosed disclaimer:

“A process of preparing a beverage or a beverage additive that involves: (a) contacting the beverage or a precursor of the beverage with cross-linking enzymes to obtain modified prolamin, and (b) remove the modified prolamin at least partially, with the proviso of excluding a method of separation of wheat flour into one gluten fraction and at least one other fraction, comprising the steps of a) mixing the flour and a liquid and a transglutaminase enzyme obtaining a dough, b) separating the dough into a fraction comprising gluten and at least one other fraction, c) recovering at least the gluten fraction”.

The Appeal Board allowed the inclusion of an undisclosed disclaimer in relation to the method of preparing a beverage. It agreed that the field of beverages is so unrelated to the field of flours that an accidental anticipation existed.

However, the Appeal Board decided that the undisclosed disclaimer was unallowable in relation to the method of preparing a beverage additive. The Board reasoned that because WO02/15713 mentions “there are a vast number of areas in which starches may be applied, such as glucose syrup production, and in sweetening production in general”, this would lead a skilled person to consider the resultant glucose-rich syrup to be suitable as a beverage additive. As WO02/15713 deals in a side aspect with the production of beverage additives, the teachings are not so unrelated and remote enough from the claimed invention to be considered an accidental anticipation.

At the end of the Appeal Proceedings, claim 1 of the granted patent has been amended to limit the process to the preparation of a beverage.

The ‘to go’ message (without a shot of hazelnut syrup…)

The invention was found to be inventive over the closest prior art in combination with WO02/15713. This document was therefore considered irrelevant for inventive step but not irrelevant enough to be an accidental anticipation.

The Board found that the requirement in G1/03, that an accidental novelty-destroying disclosure has to be completely irrelevant for assessing inventive step, is to be understood not as an alternative or additional criterion, but as a consequence of the criterion that, from a technical point of view, the disclosure is so unrelated and remote that the skilled person would never have taken it into consideration when making or working on the invention.

Although there are prescribed circumstances in which an undisclosed disclaimer may be introduced into a claim (as T1218/14 highlights), the criteria for allowability are strict. In order to distinguish an invention from the prior art it may be necessary to introduce a further technical feature into the claim.

The EPO has a stringent approach to the allowability of claim amendments. This is referred to as the “Gold Standard”. According to this, an amendment can only be made within the limits of what a skilled person would derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing from the whole of the European patent application or European patent as filed. It’s therefore recommended to include as many fall-back positions or provisos as possible within a patent application when it’s originally filed, to ensure that there’s clear and unambiguous language on which to base a suitable claim amendment that doesn’t fall foul of the Gold Standard.