CABINET CHAILLOT

T1994/22 - Purported technical effect not encompassed by the teaching of the application as filed in the sense of G 2/21, no unexpected balance of beneficial properties

G2/21, purported technical effect, balance of beneficial properties, inventive step

The appeal by the opponent ("appellant") lies from the opposition division's decision to reject the oppositions filed against European patent No. 3 275 871.
Claim 1 of the main request relates to Form II of selexipag.
The respondent relied on post-published data D32 and submitted that Form II as claimed had an improved photostability over Form III (comparative).
The appellant submitted that the application as filed made no mention of the photostability of Form II, let alone contained any evidence of it. Based on G 2/21, the respondent could not rely on the effect of improved photostability.
According to G 2/21, "a patent applicant or proprietor may rely upon a technical effect for inventive step if the skilled person, having the common general knowledge in mind, and based on the application as originally filed, would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention."
The question to be answered in the present case is thus whether the improved photostability of Form II can be derived by the skilled person, having the common general knowledge in mind, and based on the application as filed, as being encompassed by the technical teaching (requirement (i)) and embodied by the same originally disclosed invention (requirement (ii)).
The respondent relied on the statements made in T 116/18 as regards G 2/21 and submitted that the skilled person would have understood that the effect of improved photostability was implied by or at least related to the technical problem initially suggested in the originally filed application. Therefore, requirement (i), as encompassed by the technical teaching, was met. Furthermore, the skilled person would not have had any legitimate reason to doubt that the improved photostability could be achieved with the claimed polymorphic form of selexipag. Based on their common general knowledge the skilled person had been aware on the filing date that different polymorphic forms of APIs may have different, e.g. improved, photostability, and so the effect of improved photostability of selexipag Form II was not irreconcilable with the provision of a novel polymorphic form. Therefore, requirement (ii), as embodied by the same originally disclosed invention, was also met in the present case.
In the present case the board acknowledges that the mere fact that photostability or improved photostability is not contained in terms of a positive verbal statement in the application as filed and that the application as filed does not contain any data as regards photostability, as such, does not imply that the effect of improved photostability cannot be relied on in terms of G 2/21 or T 116/18.
The board also agrees with T 116/18 that the purported technical effect together with the claimed subject-matter need only be conceptually comprised by the broadest technical teaching of the application as filed and that it may also be sufficient for the skilled person, having the common general knowledge in mind, and based on the application as filed, to recognise that said effect is relevant to the claimed subject-matter; however, it is precisely this requirement that is not met in the present case.
All that is disclosed in the application as filed is a "thing of a high quality for which constant effect can be always shown and of a form which is handled easily industrially". The board does not consider such a sweeping statement which covers a plethora of potential advantageous properties to encompass photostability, let alone improved photostability. In the present case, the application as filed is in fact directed to properties entirely unrelated to photostability. Therefore, based on these properties, having the common general knowledge in mind, the skilled person would by no means have recognised that (improved) photostability is relevant to the claimed subject-matter. Going from these specific properties to the effect of photostability would also clearly change the nature of the invention, contrary to what is required by T 116/18. Hence, the effect of photostability is not encompassed by the teaching of the application as filed.
It follows that improved photostability of Form II as demonstrated in D32 cannot be taken into account in the assessment of the technical effects achieved by the distinguishing feature.
For the assessment of inventive step, the starting point is example 84 of D10 which discloses the preparation of selexipag. The distinguishing feature of claim 1 of the main request in view of example 84 of D10 is the crystalline form, namely Form II, of selexipag.
The distinguishing feature are: stability; particle size distribution, and linked to this, industrial processability; concentration of residual solvents; and level of residual impurities.
It can be concluded from experimental results that Form II exhibits the best stability but only intermediate industrial processability, intermediate residual solvent content and an intermediate amount of residual impurities. There is no balance of beneficial properties for Form II according to the main request. The objective technical problem may only be considered that of providing a crystalline form of selexipag which is the best for one property, but only intermediate for all other tested properties.
The respondent submitted that there was no reasonable expectation based on the prior art that a suggested investigation in terms of polymorph screening would be successful in finding a form of selexipag having a balance of beneficial properties in terms of stability, industrial processability, solvent content and purity.
The board disagrees. Based on T 1684/16 and T 777/08, an inventive step can be acknowledged if the claimed polymorph has an unexpected property meaning that its selection is non-arbitrary. In the present case, the board sees nothing unexpected in finding a polymorph that is optimum for one property but only intermediate for several other properties. If this were unexpected and thus gave rise to an inventive step being acknowledged, an applicant or proprietor having identified a new polymorph would simply need to carry out tests for long enough to find one single property for which the identified polymorph performs best. This might result in a situation in which almost any polymorph in the world becomes inventive, which would render Article 56 EPC meaningless.
Therefore, the selection of Form II is an arbitrary selection from the host of alternatives covered by the closest prior art. Such an arbitrary selection without any unexpected balance of properties being produced cannot contribute to inventive step.
The patent is revoked.

 

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