T 1085/13 - Novelty based on purity of compound

Key points

• The Board departs from T 0990/96 which had found "that a document disclosing a low molecular chemical compound and its manufacture makes normally available this compound to the public in the sense of Article 54 EPC in all desired grades of purity" and T 728/98 which had held that " the general rule applies that the level of purity of that low molecular compound cannot entail novelty".
• The present Board considers that a document only discloses (in the sense of Art. 54 and Art. 123 and G2/10) the purity degree as inevitably achieved by the described manufacturing method. 
• Whether with other purification methods, a higher purity can be achieved (up to the now claimed level), and whether such purification methods are common general knowledge, are a matter to be considered in the assessment of inventive step, according to the present Board.
• The interesting follow-up question is, taking into account that any degree of purity is a selection from a range of 0-100%, whether this decision means that the rules for selection inventions are to be reconsidered as well. 

EPO Headnote 
A claim defining a compound as having a certain purity lacks novelty over a prior-art disclosure describing the same compound only if the prior art discloses the claimed purity at least implicitly, for example by way of a method for preparing said compound, the method inevitably resulting in the purity as claimed.

Such a claim, however, does not lack novelty if the disclosure of the prior art needs to be supplemented, for example by suitable (further) purification methods allowing the skilled person to arrive at the claimed purity.

The question of whether such (further) purification methods for the prior-art compound are within the common general knowledge of those skilled in the art and, if applied, would result in the claimed purity, is not relevant to novelty, but is rather a matter to be considered in the assessment of inventive step


EPO T 1085/13 - link

3. Document D1

3.1 As set out above, it is undisputed that LH as prepared according to example 16 of D1 is amorphous and has a level of crystallinity as defined in claim 1 at issue. Example 16, however, does not mention the purity of the LH obtained. By reworking example 16 of D1 (Report #56, above), the LH obtained has a purity of 97.91%, which is below the lower limit required by claim 1 at issue.

Note: operative claim 1 is: "1. Amorphous Lercanidipine Hydrochloride having a purity of at least 99.5% determined by HPLC analysis and containing less than 0.5% of crystalline Lercanidipine Hydrochloride".

3.2 The board is aware that according to decision T 0990/96 (OJ 1998, 489; headnote 1 and 2 and reasons, 7 and 8), "a document disclosing a low molecular chemical compound and its manufacture makes normally available this compound to the public in the sense of Article 54 EPC in all desired grades of purity (emphasis added by the present board).

3.3 The entrusted board reached this conclusion on the basis that, particularly in the field of pharmaceutical compounds, it was "common practice for a person skilled in the art of preparative organic chemistry to (further) purify a compound obtained in a particular chemical manufacturing process according to the prevailing needs and requirements, e.g. in samples for analytical purposes. Conventional methods for the purification of low molecular organic reaction products such as recrystallisation, distillation, chromatography, etc., which normally can be successfully applied in purification steps, are within the common general knowledge of those skilled in the art" (loc. cit. emphasis added by the present board).

It was accepted by that board that exceptional situations may exist which could justify a different conclusion. For example "a situation where it was proved on the balance of probability that all prior attempts to achieve a particular degree of purity by conventional purification processes had failed". However, "the burden of proving the existence of such an extraordinary situation lies with the party alleging its existence" (loc. cit., emphasis added by the present board).

3.4 This rationale of T 0990/96 has been followed by a number of subsequent decisions. In particular, according to T 0728/98 (OJ 2001, 319; headnote 2 and reasons, 6.4), "[w]here the claimed purity level of a low molecular chemical compound ... turns out to be successfully achieved by applying a conventional purification method on a reaction mixture disclosed in the prior art, an exceptional situation such as addressed in the decision T 990/96 does not exist. This would have required evidence that conventional methods could not achieve that purity level. Therefore the general rule applies that the level of purity of that low molecular compound cannot entail novelty" (emphasis added by the present board).

3.5 The board agrees with the examining division that if the above rationale developed in T 0990/96 and T 0728/98 were to be applied to the present case, it would lead to the conclusion that since D1 in its example 16 discloses amorphous LH and its preparation, it makes this substance available to the public in the sense of Article 54 EPC in all desired grades of purity, i.e. also in the purity specified in claim 1 at issue. Under this premise, novelty of the subject-matter of claim 1 would have to be denied.

3.6 However, the board is convinced that the rationale of the above mentioned decisions is not in line with the case law developed by the Enlarged Board of Appeal, in particular in decisions G 2/88 and G 2/10, for the following reasons.

3.6.1 In decision G 2/10 (OJ, 6/2012, pages 376 to 417, point 4.7 of the reasons), the Enlarged Board stated that "the overriding principle for any amendment to be allowable under Article 123(2) EPC is that the subject-matter of an amended claim must be at least implicitly disclosed to the skilled person, using common general knowledge, in the application as filed".

The Enlarged Board (reasons, 4.6) further set out that "the European Patent System must be consistent and the concept of disclosure must be the same for the purposes of Articles 54, 87 and 123 EPC".

It follows that, in the same way as for assessing compliance with Article 123(2) EPC, in order to conclude a lack of novelty, there must be at least an implicit disclosure in the state of the art of subject-matter falling within the claimed scope.

3.6.2 The notion of implicit disclosure in the context of novelty has been defined in earlier decision T 1523/07 of 24 November 2009 as follows (point 2.4):

"[I]mplicit disclosure means disclosure which any person skilled in the art would objectively consider as necessarily implied in the explicit content, e.g. in view of general scientific laws. In this respect, the term "implicit disclosure" should not be construed to mean matter that does not belong to the content of the technical information provided by a document but may be rendered obvious on the basis of that content. Whilst common general knowledge must be taken into account in deciding what is clearly and unambiguously implied by the explicit disclosure of a document, the question of what may be rendered obvious by that disclosure in the light of common general knowledge is not relevant to the assessment of what is implied by the disclosure of that document. The implicit disclosure means no more than the clear and unambiguous consequence of what is explicitly mentioned" (emphasis added by the present board).

When discussing the case underlying T 1523/07, the entrusted board concluded that the claimed subject-matter was novel, since the relevant prior-art document did not implicitly disclose a claimed feature (rinsing until the pH value of the waste water was not more than 9 at 50 °C). The entrusted board held that although the skilled person may have known that implementing the claimed feature was desirable, this feature did "not inevitably result" from the teaching of the prior-art document.

Numerous decisions have adopted the same line of reasoning either with respect to the assessment of novelty (e.g. T 2522/10 of 16 April 2015, point 4; T 1383/12 of 20 September 2016, point 5.1.1; T 0572/14 of 28 September 2016, point 4.2; T 1723/12 of 11 January 2017, point 3.1) or of Article 123(2) EPC (e.g. T 1890/15 of 19 December 2017, point 3.2; T 0648/13 of 15 February 2018, point 7; T 0049/13 of 1 June 2018, point 13; T 2267/14 of 23 July 2018, point 3.1).

3.6.3 This approach is also in line with decision G 2/88 (OJ, 4/1990, pages 93 to 113). In that decision (reasons, 10), the Enlarged Board, with reference to Article 54(2) EPC, made clear that the "word 'available' [to the public] carries with it the idea that, for lack of novelty to be found, all the technical features of the claimed invention in combination must have been communicated to the public" (insertion and emphasis added by the present board). The Enlarged Board also stated (loc. cit.) that "teaching the carrying out of a process for example, also makes available further information which is the inevitable result of carrying out such teaching" (emphasis added by the present board).

3.6.4 The present board therefore concludes that the skilled person, using his common general knowledge, would understand a feature as implicitly disclosed in a prior-art disclosure only if it is the clear and unambiguous consequence, and hence the inevitable result of what is explicitly derivable from said prior art disclosure. Consequently, common general knowledge can be used in order to assess how the skilled person would understand the disclosure of the prior art, but cannot be used to supplement it.

3.7 A claim defining a compound as having a certain purity therefore lacks novelty over a prior-art disclosure describing the same compound only if the prior art discloses the claimed purity at least implicitly, for example by way of a method for preparing said compound, the method inevitably resulting in the purity as claimed.

Such a claim, however, does not lack novelty if the disclosure of the prior art needs to be supplemented, for example by suitable (further) purification methods allowing the skilled person to arrive at the claimed purity.

3.8 The question of whether such (further) purification methods for the prior-art compound are within the common general knowledge of those skilled in the art and, if applied, would result in the claimed purity, is not relevant to novelty, but is rather a matter to be considered in the assessment of inventive step.

3.9 This conclusion is in line with the statement made by the Enlarged Board in G 2/88 (reasons, 10) that "a line must be drawn between what is in fact made available, and what remains hidden or otherwise has not been made available" and that "the distinction should also be emphasised between lack of novelty and lack of inventive step ... in particular, what is hidden may still be obvious". The conclusion is also in agreement with decision T 1523/07 of 24 November 2009, cited above.

3.10 Moreover, this conclusion conforms with the well-established Enantiomers decision T 0296/87 (OJ, 5/1990, pages 195 to 212, reasons, 6.4) stating that "the only technical teachings prejudicial to novelty [of chemical substances] are those which disclose a substance as the inevitable result of a prescribed method or in specific, i.e. individualised, form" (emphasis and insertion added by the present board). With respect to the question of novelty of a specific enantiomer over the disclosure of racemates, the entrusted board stated (reasons, 6.5, 7.1) that "any consideration of the possibility of racemate separation or enantiomer enrichment must be ruled out in the assessment of novelty" and that these considerations "will be more usefully applied to the examination as to inventive step" (emphasis added by the present board).

3.11 The rationale of T 0990/96 and T 0728/98 (3.2, 3.4, supra) is thus not compatible with the case law developed by the Enlarged Board and the above discussed case law of the boards of appeal.

3.12 By applying that case law to the present case, it follows firstly that the purity of the amorphous LH produced according to example 16 of D1 is not explicitly disclosed. Secondly, Report #56 demonstrates that a purity falling within the claimed range is not the inevitable result, and thus not an implicit feature, of the preparation method taught in said example. There is also no teaching at all in D1 to modify this process such that an even higher purity of at least 99.5% as required by claim 1 at issue is achieved.

4. For the reasons given above, a purity as claimed is neither explicitly nor implicitly disclosed in documents D1 and D2/D3. The board therefore comes to the conclusion that the subject-matter of claim 1 at issue, of claim 2 dependent on claim 1, and of claim 3 directed to the medical use of the product of claim 1, is novel over documents D1 to D3 (Articles 52(1) and 54 EPC).