Zusammenfassung von EPC2000 Art 056 für die Entscheidung T0672/21 vom 15.04.2024

In T 672/21 the appellant (opponent 2) had provided submissions on obviousness based on the assumption that any improved property was absent, so that the objective technical problem was the mere provision of a further polymorph. It relied in this respect on decision T 777/08. The board, however, defined the objective technical problem in a more ambitious way. For this reason alone, the board held the appellant's submission on obviousness had to fail. The objective technical problem as defined by the board was the provision of a crystalline form of selexipag with a balance of beneficial properties, namely an intermediate stability and at the same time improved industrial processability and improved purity in terms of reduced amounts of residual solvents and residual impurities. The board noted that according to T 777/08 "in the absence of any technical prejudice and in the absence of any unexpected property, the mere provision of a crystalline form of a known pharmaceutically active compound cannot be regarded as involving an inventive step" (headnote 1) and "the arbitrary selection of a specific polymorph from a group of equally suitable candidates cannot be viewed as involving an inventive step" (headnote 2). However, in the present case there was no absence of unexpected properties and the selection was not arbitrary, since the selected Form I had a balance of beneficial properties in terms of stability, industrial processability and purity in comparison with Form II and Form III. There was nothing in the prior art which pointed to the fact that the claimed Form I would have this balance of beneficial properties and they were thus not expected. The present case thus differed from the situation at issue in decision T 777/08. The board also distinguished T 41/17, relied upon by the appellant for its further argument that the alleged stability of Form I was not a surprising technical effect because the skilled person always looked for the most thermodynamically stable polymorph in order to avoid the problem of interconversion within the dosage form. In T 41/17 it was concluded that the skilled person would have performed screening of the different polymorphs disclosed in the closest prior art, which could exist in order to isolate and identify the most thermodynamically stable form thereof. By doing so, the skilled person would have arrived at the claimed polymorph, which was the most thermodynamically stable form and which, for this reason, was expected not to convert to other forms under mechanical stress. However, unlike in T 41/17, in the present case the stability was not the only property, but rather part of a balance of beneficial properties. Hence, even if the stability of Form I (which is at an intermediate level) had been expected, the same would not apply to the balance of various beneficial properties. The board also noted that the mere fact that the skilled person would have carried out routine screening for polymorphs as such did not render the claimed Form I obvious. As set out in T 1684/16, the fact that the skilled person was taught in the prior art to investigate polymorphs in order to isolate the crystalline form having the most desirable properties was in itself not necessarily sufficient to consider a specific polymorphic form having a certain desired property or, as in the present case, balance of properties obvious. Thus the subject-matter of claim 1 of the main request, and by the same token of claims 2 to 13, which included the subject-matter of claim 1, involved an inventive step in view of D10 as the closest prior art.