T 0638/21 - A non-novel second non-medical use

Key points

•  Claim 1 of the patent is directed to: "1. Use of N-n-butylpyrrolidone as a non­-reprotoxic solvent."
• The prior art discloses the use of N-n-butylpyrrolidone (NBP) as a solvent but does not mention non­-reprotoxicity.
• "The board notes that D1 (page 1, lines 1-7) discloses compositions intended for topic application, with the solvent used (for example NBP) facilitating the absorption by the skin of ingredients having cosmetic or medical properties. In the board's view, such solvated compositions were implicitly held non-toxic at the filing date of D1, since they were supposed to be absorbed by the skin." 
• "Since NBP was moreover not classified as being reprotoxic at the publication date of D1, the skilled reader would at this date have understood from D1 that the solvent used was also inherently non-reprotoxic and could be commercialised without any warning label and freely used by any possible group of users. " 
• "The present case thus differs from a new therapeutic application wherein an unknown therapeutic effect can be discovered by clinical trials. This conclusion in line with established case law, for example T 1523/07, reasons 2.4, according to which "implicit disclosure means disclosure which any person skilled in the art would objectively consider as necessarily implied in the explicit content".
• "differently from the uses considered in decisions G 2/88 and G 6/88 that clearly concerned a technical effect (namely friction reduction and fungi control, respectively) different from those already known for the substance in question, and wherein the known chemical substance was purposively applied to achieve the new technical effect, the use of NBP as a non-reprotoxic solvent, even if considered to be a purposive application, underlies that already disclosed in D1."
• "This conclusion is supported by case law, for example that in T 892/94 (OJ 2000, 1, notes II) which concluded that "... a newly discovered technical effect does not confer novelty on a claim directed to the use of a known substance for a known non-medical purpose if the newly discovered technical effect already underlies the known use of the known substance."
• "the board concludes that the label of the use of NBP as "non-reprotoxic" solvent is merely an explanation of the non-toxicity already inherently known from D1 by means of its use for absorption by human skin, which use cannot distinguish the claimed use from the known one."
• The patent is revoked.
• 
  

EPO 

The link to the decision is provided after the jump, as well as (an extract of) the decision text.

https://www.epo.org/en/boards-of-appeal/decisions/t210638eu1

1. Main request (patent as granted) - Novelty (Article 54 EPC)

1.1 The board preliminary notes that claim 1 at issue relates to the use of N-n-butylpyrrolidone (NBP) as a non­-reprotoxic solvent, without however explicitly identifying the means of realisation for the claimed use, which thus encompasses any means of application of a solvent being part of common general knowledge.

1.1.1 As to the meaning of the term "non-reprotoxic" the patent states (paragraph [0029]) that it identifies a chemical substance which results to be non-reprotoxic following the evaluation according to the EC regulation no. 1272/2008 of 16 December 2008 (document D12), and its amendments up to November 2012.

D12, which classifies chemical substances which are a hazard to the human health (see page 1, paragraph 1 and page 6, paragraph 54), discloses at page 107, paragraph 3.7.7.1, that reproductive toxicity concerns adverse effects on sexual function and fertility in adult males and females as well as developmental toxicity in the offspring.

A similar definition for "reprotoxicity" is found in the common general knowledge shown in D22 (page 999, table 34.8, point 7), filed with the grounds of appeal by the appellant, and for which no objection under Article 12(4) RPBA against the admissibility was raised by the respondent. The board has also no reason to disregard it as it represents common general knowledge.

D12 further explains (page 108-110, paragraphs 3.7.2.1.1 to 3.7.2.2.3; page 112, paragraph 3.7.2.5) that a given chemical compound (or mixture) is classified as reprotoxic on the basis of the total weight of evidence provided (see also Chapter 1, pages 11-13), following the evaluation based on internationally accepted test methods (see also Chapter 2, pages 13-15). As stated in D12 (page 109, paragraph 3.7.2.2.1), classification as a reproductive toxicant is intended to be used for substances which have an intrinsic, specific property to produce an adverse effect on reproduction, and substances shall not be so classified if such an effect is produced solely as a non-specific secondary consequence of other toxic effects.

It was further established from the documents D23 to D26 that the definition of a "reprotoxic" substance and the criteria used for classification have not changed in the versions of D12 amended up to November 2012.

1.1.2 It follows from the above considerations that the term "non-reprotoxic" used in claim 1 at issue can only be understood as relating to a solvent which is not classified as reprotoxic according to an evaluation carried out within the terms of D12. This however does not exclude that a solvent could be classified as reprotoxic at a later stage, since the tests used for evaluation or the established threshold at which the potentially toxic substance is considered to be a hazard may vary in the course of time.

This is confirmed by the patent in suit (paragraph [0007]) which discloses that N-methylpyrrolidone (NMP) was classified as "reprotoxic category 2" only from 1st December 2010 as shown in D26 (page 702), whilst it was not classified as such in the older document D12 (page 520), so that from that date mixtures containing 3% or more of NMP had to be labeled as being reprotoxic (see D26, page 162 and D12, page 113).

1.2 As regards the claimed use, it is undisputed that document D1 (claims 1 and 5; examples 3, 9 and 14) already discloses the use of NBP as a solvent.

The respondent argued that D1 did not disclose that NBP was on-reprotoxic, and so the purpose "non-reprotoxic solvent" defined in the claimed use would represent a technical feature within the terms established by decisions G 2/88 (OJ 1990, 93, catchword 3) and G 6/88 (OJ 1990, 114, catchword) reading :"A claim to the use of a known compound for a particular purpose, which is based on a technical effect which is described in the patent, should be interpreted as including that technical effect as a functional technical feature, and is accordingly not open to objection under Article 54(1) EPC provided that such technical feature has not previously been made available to the public".

The respondent argued that the technical effect related to "non-reprotoxicity" consisted in allowing a group of persons such as pregnant women or would-be parents, which are potentially affected by reprotoxic substances, to be exposed to the solvent without the need for additional protective measures against a possible hazard arising from it, thus saving e.g. costs in the management of a chemical plant wherein the solvent is used since more stringent safety measures do not need to be implemented. Therefore, the thus defined purpose was a technical feature which provides novelty over the use disclosed in D1.

1.3 The board notes that D1 (page 1, lines 1-7) discloses compositions intended for topic application, with the solvent used (for example NBP) facilitating the absorption by the skin of ingredients having cosmetic or medical properties. In the board's view, such solvated compositions were implicitly held non-toxic at the filing date of D1, since they were supposed to be absorbed by the skin.

Since NBP was moreover not classified as being reprotoxic at the publication date of D1, the skilled reader would at this date have understood from D1 that the solvent used was also inherently non-reprotoxic and could be commercialised without any warning label and freely used by any possible group of users. This understanding remained unchanged till the contrary is discovered, as explained above in the case of NMP. This conclusion is further in agreement with D12 and its amended versions up to 2012, which documents were used in the patent for defining non-reprotoxicity and which in fact do not list NBP as a reprotoxic substance. In the board's view it can also be derived from D12, used in the patent for defining the word "non-reprotoxic", that all chemical substances not classified therein were still to be considered at the publication date of the above regulations not to be a hazard and thus to be non-reprotoxic within the meaning of the patent.

1.3.1 The respondent additionally argued that the non-reprotoxicity of NBP was hidden in D1 and was thus a feature not available to the public. The present case was in particular similar to the use of a compound for achieving a therapeutic effect which can only be discovered by clinical testing and that therefore the non-reprotoxic feature was hidden in accordance with the conclusions in G 1/92 (OJ 1993, 277, reasons 3).

1.3.2 The board cannot follow this argument because, as explained above, NBP was not held reprotoxic by the skilled person at the publication date of D1 or even later at the publication date of D12 and its amended versions. The present case thus differs from a new therapeutic application wherein an unknown therapeutic effect can be discovered by clinical trials. This conclusion in line with established case law, for example T 1523/07, reasons 2.4, according to which "implicit disclosure means disclosure which any person skilled in the art would objectively consider as necessarily implied in the explicit content".

And even though the non-reprotoxicity of a solvent manifests only when a particular group of persons (pregnant women or would-be parents) is exposed to it, being an intrinsic property of said solvent, it is still present therein irrespective of the group of persons exposed to it. Claim 1 at issue being furthermore not limited to a use by a specific group of persons or to a particular application which would need additional safety requirements or not, in the board's view, the property of NBP being non-reprotoxic was inherently available to the public in view of the specific use of the solvent in D1 requiring the solvent to be non-toxic.

As to the tests in the patent, which are supposed to show the non-reprotoxicity of NBP, they merely confirm what was already the understanding of the skilled person at the priority date of the patent taking into account the prior art and common general knowledge. Moreover, the fact that there was an interest to confirm the non-toxicity of N-alkyl pyrrolidone derivatives since NMP was found to be reprotoxic underlies only the known striving of the concerned authorities to classify chemical substances which are a hazard to the human health in order to provide adequate protection.

1.3.3 In the board's view, differently from the uses considered in decisions G 2/88 and G 6/88 that clearly concerned a technical effect (namely friction reduction and fungi control, respectively) different from those already known for the substance in question, and wherein the known chemical substance was purposively applied to achieve the new technical effect, the use of NBP as a non-reprotoxic solvent, even if considered to be a purposive application, underlies that already disclosed in D1.

This conclusion is supported by case law, for example that in T 892/94 (OJ 2000, 1, notes II) which concluded that "... a newly discovered technical effect does not confer novelty on a claim directed to the use of a known substance for a known non-medical purpose if the newly discovered technical effect already underlies the known use of the known substance." or T 186/98 (reasons 3) according to which "... there must be a new technical application or use which is not necessarily correlated with the known application or use and can be clearly distinguished therefrom .... The mere explanation of an effect obtained when using a known compound for a known purpose cannot confer novelty on a claim...".

1.3.4 For all the above reasons, the board concludes that the label of the use of NBP as "non-reprotoxic" solvent is merely an explanation of the non-toxicity already inherently known from D1 by means of its use for absorption by human skin, which use cannot distinguish the claimed use from the known one.

1.4 The board thus concludes that D1 already discloses the use of NBP as a non-reprotoxic solvent so that the subject-matter of claim 1 at issue lacks novelty under Article 54 EPC.