Of Molecules & Medicine: Added Subject-Matter at the EPO – Selection from Convergent Lists

By Michael Ford, Senior Associate

The European Patent Office has a reputation for taking a strict approach to the assessment of added subject-matter. Objections can be raised when claim amendments combine features pertaining to different lists of features disclosed in the application as filed. A recent Board of Appeal decision, however, may provide applicants and patent proprietors with greater scope to amend claims based on the selection of features from different lists.

In particular, a central question in EPO Technical Board of Appeal decision T 1621/16 (an appeal from a decision of the Opposition Division) was whether, and under which circumstances, claim amendments based on multiple selections from lists of converging alternatives comply with Article 123(2) EPC.

Existing law

Article 123(2) EPC prohibits amendments which extend the subject-matter of an application or patent beyond the content of the application as filed. Case law has confirmed that the underlying idea is that an applicant or patent proprietor should not be allowed to improve its position by adding subject-matter not disclosed in the application as filed, as this would give rise to an unwarranted advantage and could be damaging to the legal security of third parties relying on the content of the original application. Following the Enlarged Board of Appeal decision in G 2/10, an amendment is regarded as introducing subject-matter which extends beyond the content of the application as filed, and which is therefore unallowable, if the overall change in the content of the application or patent results in the skilled person being presented with information which is not directly and unambiguously derivable from the application as filed, even when account is taken of matter which is implicit to a person skilled in the art. This test is known as the ‘gold standard’.

The Boards of Appeal have developed various rules for determining whether particular types of amendment comply with Article 123(2) EPC. A particular class of amendments, which are commonly made to applications in the chemical and life sciences fields, involves the selection or deletion of claim features from lists.

A claim amendment which consists of selecting a feature from a single list does not generally present a problem at the EPO. However, the arbitrary selection of features from multiple lists of features is generally considered to breach Article 123(2) EPC, unless there is a clear pointer in the application as filed to the specific combination of features.

For example, where an application discloses a list of possible metal elements (e.g. iron, aluminium, copper and zinc) and a list of possible non-metal elements (e.g. oxygen, nitrogen, fluorine and chlorine), a claim to a composition comprising a metal element and a non-metal element cannot be amended to recite the specific combination of iron and oxygen, unless the application as filed contains a pointer towards the specific combination (such as a statement that the particular combination of iron and oxygen is ‘preferred’).

EPO case law also permits the deletion of items from a list as long as the deletion does not result in the singling out of a particular combination of features not disclosed in the application as filed. The deletion must maintain the remaining subject-matter as a ‘generic group’ and must not define a new invention having a previously undisclosed technical effect.

T 1621/16

Much of the existing EPO case law is concerned with amendments based on lists of equivalent or non-converging alternatives, which are features which are either mutually exclusive or only partially overlapping in scope (e.g. iron, aluminium, copper, zinc).

In T 1621/16, however, the Board had to consider how to assess compliance with Article 123(2) EPC when multiple selections are made from lists of converging alternatives, which are lists of options ranked from the least preferred to the most preferred, each of the more preferred alternatives being fully encompassed by all of the less preferred and broader options in the list (e.g. element, metal, transition metal, iron). A key question was whether it is permissible to combine more and less preferred alternatives from different lists. The Opponent and the Opposition Division had argued that amendments based on the selection of two or more intermediate options (i.e. different from the most preferred options) from different convergent lists were not allowed and that only alternatives having the same degree of preference could be combined (if at all).

The Board reviewed the existing case law on the matter and found it to be inconsistent. Nevertheless, the Board concluded that the selection of features from multiple lists of convergent alternatives does comply with Article 123(2) EPC if:

i) the claimed combination of features is not associated with an undisclosed technical contribution; and

ii) there is a pointer to the claimed combination in the application as filed.

Condition (i) was required as the patent proprietor should not derive an unwarranted advantage from linking the specific combination of more and less preferred alternatives to an inventive selection which is not supported by the application as filed. Condition (ii) is required so that the selection is not arbitrary and would be satisfied where the amended claim converges towards one or more examples or specific embodiments disclosed in the application as filed, since these generally represent the most detailed and preferred forms of the invention. An explicit statement in the application as filed that a particular combination of features is ‘preferred’ does not appear to be required.

The Board arrived at these conclusions by comparing the selection from converging lists to (a) selection from non-converging lists and (b) the deletion of options from non-converging lists. The Board noted that while selection from non-converging lists leads to a singling out of an invention from among several distinct alternatives, the elements of a converging list do not represent distinct features but rather more or less restricted versions of the same feature. Selection from converging lists therefore does not lead to a singling out of an invention but simply to a more or less restricted version of the originally-claimed subject-matter. This is analogous to the permissible deletion of options from non-converging lists, which also merely restricts the scope of protection.

When considering the particular amendments which had been made in T 1621/16, the Board also found that it was allowable to combine a single selection of a preferred element from a non-convergent list with multiple selections from convergent lists without adding subject-matter.

Knock-on effect?

There is a symmetry between the examination of added-subject matter and novelty at the EPO. In both cases, the key question is what is directly and unambiguously disclosed in the relevant document (i.e. the application as filed when assessing added-subject matter or the prior art when assessing novelty). Accordingly, there is a question whether the conclusions in T 1621/16 could affect the way novelty is assessed at the EPO. For example, it is established case law that the monodimensional selection of a feature from a single list of features disclosed in the prior art does not confer novelty on a claim, but a claimed combination which requires selection of features from two or more lists of a certain length is novel. However, is novelty still conferred when the lists in the prior art converge?

The EPO has also recently moved away from taking into account technical effect when assessing the novelty of selection inventions, on the basis that this is more a matter for inventive step. However, the decision in T 1621/16 requires an assessment of whether there is an undisclosed technical contribution associated with the claimed combination of features when determining compliance with Article 123(2) EPC. Does this mean that the technical contribution should also be considered when assessing the novelty of selections from multiple converging lists?

It is hoped that future decisions will address these issues.

Practice points

The decision in T 1621/16 provides applicants and patent proprietors with arguments which may be helpful when defending amendments based on selections from converging lists before the EPO.

However, as noted in the decision itself, the case law on this matter is not yet consistent and without a decision of the Enlarged Board of Appeal, one cannot be certain that a different Board would come to the same conclusions. European examiners, who in practice rely predominantly on the EPO’s consolidated Guidelines for Examination (rather than the decisions of the Boards of Appeal), may also continue to object to this type of amendment.

When drafting applications bound for European prosecution, it therefore remains good practice to include explicit basis for different combination of claim features which might be envisaged, and in particular different combinations of more and less preferred options, whenever this is possible. It can in this regard be helpful when drafting to compare the broadest statement of the invention with the specific examples, and to build in explicit basis for particular combinations of options which gradually transition from the broadest statement of the invention to each specific example.