T 1654/22 - Counting to two with the Boards

Key points

• If a claim is novel by involving two selections from two lists, how many distinguishing features does it have?
• D2, claim 36 teaches a preparation method with as one component, "a local anaesthetic selected from the group consisting of amide and ester type local anaesthetics or a combination thereof
  
• The Board: "Mepivacaine is explicitly disclosed in the list of suitable anaesthetics recited in [the description of D2]. An embodiment of the method of claim 36 wherein the local anaesthetic is mepivacaine thus results from a single selection in D2 and is part of the direct and unambiguous disclosure of D2. " The Board refers to this embodiment as embodiment a).
• "The opposition division concluded that the subject-matter of the main request and auxiliary requests 1-8 was anticipated by the method of claim 36 of D2 as applied to mepivacaine, and thus clearly considered this embodiment a) to belong to the state of the art under Article 54(2) EPC. Nonetheless, the opposition division disregarded the same embodiment a) as starting point for the assessment of inventive step, for lack of an example or pointer to this embodiment. The appellant - proprietor also submits that embodiment a) is not a suitable starting point for the assessment of inventive step."
• "The Board does not concur with these positions.

  There is no requirement in the case law that an embodiment of the state of the art must be exemplified for it to be considered in the assessment of inventive step. There is likewise no requirement that the prior art contains any pointer, suggestion or incentive to select a particular embodiment for further development for this embodiment to qualify as a starting point in the problem solution approach."

• "The mere fact that the use of mepivacaine is not exemplified does not mean either that D2 is speculative or not enabled in this respect. This is because D2 discloses examples showing the successful use of other anaesthetics, namely bupivacaine, tetracaine and, especially, the closely related lidocaine, whose physicochemical and pharmaceutical properties are very similar to those of mepivacaine"

• "For these reasons, the above embodiment a), i.e. the method of claim 36 of D2 as applied to mepivacaine, is taken as starting point for the assessment of inventive step."

• The Board hence considers the embodiment a) to be disclosed and finds that claim 1 add two further distinguishing features. However, these features are deemed to be obvious.

• The answer to the question at the beginning of this post is, therefore, one distinguishing feature.

EPO 

You can find the link to the decision and an extract of it after the jump.

https://www.epo.org/en/boards-of-appeal/decisions/t221654eu1

1. Main request, inventive step

1.1 Choice of the starting point

1.1.1 The invention in the patent in suit relates to the field of sterile and injectable compositions comprising hyaluronic acid, especially soft tissue filler compositions, and is directed to a method of preparing such compositions, comprising in particular the addition of mepivacaine hydrochloride as anaesthetic agent. The patent mentions among other properties that a filler composition obtained according to the method of the invention, including mepivacaine hydrochloride as anaesthetic agent, may be sterilized without significantly affecting the stability of the hyaluronic acid gel (see e.g. paragraph [0027]).

1.1.2 D2 is also concerned with the provision of injectable hyaluronic acid compositions comprising a hyaluronic acid and an anaesthetic agent. The compositions of D2 additionally contain an ascorbic acid derivative in an amount which prevents or reduces the effect on the viscosity and/or elastic modulus G' of the composition caused by the local anaesthetic upon sterilisation by heat (see the abstract). D2 thus belongs to the same field of anaesthetic-containing filler compositions and addresses the same problem of (rheological) stability upon sterilisation.

1.1.3 Within D2, three different starting points were debated by the parties:

a) the method of claim 36 of D2 as applied to mepivacaine (see 1.1.4 below);

b) the examples of D2 comprising lidocaine hydrochloride as anaesthetic (e.g. example 1);

c) the examples of D2 comprising bupivacaine as anaesthetic (see example 6).

1.1.4 Regarding the above embodiment a), claim 36 of D2 generally discloses a method of manufacturing a hyaluronic acid composition comprising:

a) mixing

-a hyaluronic acid,

- a local anaesthetic selected from the group consisting of amide and ester type local anaesthetics or a combination thereof, and

- an ascorbic acid derivative in an amount which prevents or reduces the effect on the viscosity and/or elastic modulus G' of the composition caused by the local anaesthetic upon sterilization by heat, and

b) subjecting the mixture to sterilization by heat.

Mepivacaine is explicitly disclosed in the list of suitable anaesthetics recited in D2 (see page 8, line 17; see also claim 8). An embodiment of the method of claim 36 wherein the local anaesthetic is mepivacaine thus results from a single selection in D2 and is part of the direct and unambiguous disclosure of D2. Contrary to the appellant - proprietor's view, it is for that purpose not required to additionally make a selection among amide and ester type local anaesthetics, because the single selection of mepivacaine necessarily means that the anaesthetic belongs to the amide group comprising mepivacaine, and is sufficient to arrive at the above mepivacaine embodiment.

In other words, a method comprising mixing a hyaluronic acid, mepivacaine and an ascorbic acid derivative, and then subjecting the mixture to sterilization by heat, belongs to the state of the art.

1.1.5 Under Article 56 EPC, an invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art. The state of the art is as defined in Article 54(2) EPC.

In the case at hand, the opposition division concluded that the subject-matter of the main request and auxiliary requests 1-8 was anticipated by the method of claim 36 of D2 as applied to mepivacaine, and thus clearly considered this embodiment a) to belong to the state of the art under Article 54(2) EPC. Nonetheless, the opposition division disregarded the same embodiment a) as starting point for the assessment of inventive step, for lack of an example or pointer to this embodiment. The appellant - proprietor also submits that embodiment a) is not a suitable starting point for the assessment of inventive step.

The Board does not concur with these positions.

There is no requirement in the case law that an embodiment of the state of the art must be exemplified for it to be considered in the assessment of inventive step. There is likewise no requirement that the prior art contains any pointer, suggestion or incentive to select a particular embodiment for further development for this embodiment to qualify as a starting point in the problem solution approach.

The criteria developed in the case law are mainly that the starting point, or "closest prior art", is normally a prior art document disclosing subject-matter conceived for the same purpose or aiming at the same objective as the claimed invention and having the most relevant technical features in common (see the Case Law of the Boards of Appeal, 10**(th) edition, 2022, I.D.3.1). These is no debate that D2, including any of its embodiments a)-c) identified above, meet these criteria.

But beyond these broad criteria, it is also established case law that, if the skilled person has a choice of several workable routes which might lead to the invention, the rationale of the problem and solution approach requires that the invention be assessed relative to all these possible routes, before an inventive step can be acknowledged. Conversely, if the invention is obvious to the skilled person in respect of at least one of these routes, then an inventive step is lacking. If an inventive step is to be denied, the choice of starting point needs no specific justification, because the claimed invention must be non-obvious having regard to any prior art (see T 261/19, point 2.5 of the reasons; T 1112/19, point 2.1.3; T 574/19, point 2.2.3).

1.1.6 The Board further considers that the disclosure in D2 relating to mepivacaine is neither defective nor speculative. Contrary to the appellant - proprietor's view, no prejudice is shown to have existed at the relevant date against the use of mepivacaine in hyaluronic acid compositions. The sole document on which the appellant - proprietor based this argument is D13 (see paragraphs [0028]-[0031]), which is a single patent application document originating from appellant - opponent 3 and filed after the filing date of the patent in suit. D13 is not suitable for establishing the existence of a prejudice, i.e. a widely held but incorrect opinion of a technical fact, at the relevant date.

The mere fact that the use of mepivacaine is not exemplified does not mean either that D2 is speculative or not enabled in this respect. This is because D2 discloses examples showing the successful use of other anaesthetics, namely bupivacaine, tetracaine and, especially, the closely related lidocaine, whose physicochemical and pharmaceutical properties are very similar to those of mepivacaine, as shown in D8 (see Table 8-1) and D9 (see page 144). Considering in particular that the pKa of mepivacaine is barely different from that of lidocaine (7.6 vs 7.7 according to D8), the appellant - proprietor's argument regarding the expected unsuitability of mepivacaine for the preparation of hyaluronic acid - anaesthetics compositions due to its pKa and the resulting high risk of precipitation, is not convincing. The observation in D2 that anaesthetics other than benzocaine are weak bases with pKa values mainly in the range 8-9 does not give cause to expect any more problems with mepivacaine than with the exemplified lidocaine (see D2, page 7, line 35 to page 8, line 2). On the contrary, the same passage indicates that, as a result of their similarity, these anaesthetics "may be expected to have similar chemical and physical effects on the hyaluronic acid composition". There is accordingly no reason to regard the mention of mepivacaine in D2 as an unrealistic starting point.

Lastly, even if, at the filing date of the patent, only dermal fillers comprising lidocaine hydrochloride were marketed, the prior art for the assessment of inventive step is not limited to such marketed products.

For these reasons, the above embodiment a), i.e. the method of claim 36 of D2 as applied to mepivacaine, is taken as starting point for the assessment of inventive step.

1.2 Differences

Starting from this general method of claim 36 of D2 as applied to mepivacaine, the method of claim 1 of the main request differs by:

- the specific use of mepivacaine hydrochloride as anaesthetic, and by

- the specific order of addition required by step b of claim 1, namely the addition of mepivacaine to a gel of hyaluronic acid.

In this respect, the Board concurs with the appellant - proprietor that these features are neither expressly mentioned in D2 in relation with mepivacaine, nor derivable from the examples, wherein anaesthetics other than mepivacaine are used. A combination of the general teaching of claim 36, as applied to the mepivacaine alternative of page 8, with some features of the examples using other anaesthetics would amount to combining features from separate embodiments in D2, and would not meet the condition that, for an item to be part of the state of the art, the claimed features in combination must be directly and unambiguously derivable from the prior art. While it may be obvious to use the conditions and salt form shown for lidocaine when putting the teaching of claim 36 as applied to mepivacaine into practice, this does not suffice for D2 to anticipate claim 1.

Thus, the order of addition, i.e. the addition of mepivacaine to a gel of hyaluronic acid, can neither be directly derived from the impermissible combination of separate items of D2 (namely the lidocaine examples and the mention of mepivacaine on page 8), nor does it implicitly, i.e. inevitably, follow from the general teaching of claim 36 of D2, since a process whereby hyaluronic acid is swelled with a solution already comprising the mepivacaine anaesthetic is also conceivable.

Likewise, the use of mepivacaine hydrochloride is neither expressly disclosed in D2 nor is the inevitable result of carrying out the teaching of D2. Page 8 of D2 merely recites "mepivacaine" without specifying that it is in the form of a salt, let alone a hydrochloride. Even if it were assumed that a salt must be used because the free base would be water insoluble, there is no direct and unambiguous teaching in D2 that this salt must have received regulatory approval, i.e. be the hydrochloride.

1.3 Technical problem

No particular technical effect has been shown to arise from the choice of the claimed order of addition, or the selection of the hydrochloride salt. The appellant - proprietor, while contesting that the above embodiment a) would be a suitable starting point, did not allege that the claimed process would achieve any particular advantage in case embodiment a) was taken as starting point for the assessment of inventive step. The comparative data relied on by the appellant - proprietor (see in particular examples 1 and 2 of the patent) aim to show an improved stability upon sterilization resulting from the choice of mepivacaine over the known lidocaine compositions, but they are not relevant to the present approach where the composition of embodiment a), which already contains mepivacaine, is chosen as starting point. The same conclusion applies to the data presented in D13 (see tables 1-6 and 25; paragraphs [0415] and [0429]): there is no demonstration of any technical effect finding its origin in the differentiating features in this case, namely the order of addition and the choice of the hydrochloride salt for mepivacaine.

Consequently, the technical problem to be solved is the provision of an alternative method for preparing a hyaluronic acid composition.

1.4 Obviousness

For the reasons given above (see 1.1.5 and 1.1.6), the disclosure in D2 of a method for the preparation of mepivacaine-containing hyaluronic acid compositions is neither speculative nor deficient, and the skilled person has no ground to expect any particular difficulty in carrying out this teaching of D2. There is no convincing reason why the skilled person would not elect to start from this embodiment a).

Since embodiment a) is disclosed in a general manner in D2, a skilled person seeking to implement this method would in an obvious manner choose the conditions and the type of salt as used in the examples of the same document in the context of other anaesthetics, such as lidocaine (see e.g. claim 1). In these examples, lidocaine is employed in the form of a hydrochloride salt, and the order of addition is as defined in claim 1, namely the anaesthetic is added to the gel of hyaluronic acid. The skilled person, starting from D2 and putting the general method of claim 36 as applied to mepivacaine into practice, would, without exercise of any inventive skill, apply to mepivacaine these conditions shown for lidocaine and would thereby expect to solve the above technical problem, which is merely the provision of an alternative.

Lastly, the common general knowledge that mepivacaine is more costly than lidocaine (see D12, last page) is a foreseeable disadvantage which does not confer an inventive step to the claimed method.

Accordingly, the main request does not meet the requirements of inventive step.