T 1147/16 - Bonus effect

Key points

• This is an opposition appeal about inventive step. The Board finds that the distinguishing feature provides for the technical effect of "reduction of epimerisation". The Board also finds that none of the cited documents teaches that the feature at issue (adding lactose) will reduce epimerisation. The opponent then argues that adding lactose is well-known to provide for "a more general stabilisation effect", such that "the particular effect of reduction of epimerisation" is a bonus effect which can not provide for inventive step.
• The Board: "As stated in T 227/89, in determining which effect is crucial and which is merely accidental (the so-called "bonus effect"), a realistic approach has to be taken, considering the relative technical and practical importance of those effects in the circumstances of a given case." 
• The Board then turns to the technology at issue and concludes that "the known potential use of lactose to stabilise lyophilisates does not equate with the specific effect of lactose on [] epimerisation disclosed in the patent, nor does this known optional use justify that the crucial epimerisation problem be disregarded in the assessment of inventive step."

T 1147/16 - link

11.5 The appellants-opponents 1 regard the particular effect of reduction of epimerisation as a bonus effect, with the consequence that the known more general stabilisation effect of lactose on lyophilisates would render the claimed subject-matter obvious. The Board does not agree.

As stated in T 227/89, in determining which effect is crucial and which is merely accidental (the so-called "bonus effect"), a realistic approach has to be taken, considering the relative technical and practical importance of those effects in the circumstances of a given case.

It is not contested that lactose is one of many commonly known bulking agents that may optionally be used to physically stabilise lyophilisates. However, as submitted by the appellant-patent proprietor, there is no suggestion in the art that a bulking agent is needed for a tigecycline composition, let alone desired (see D37, paragraph 29). In contrast, the issue of tigecycline C-4 epimerisation appears crucial considering that the C-4 epimer lacks the anti-bacterial efficacy of tigecycline, and that the epimerisation rate of tigecycline is particularly fast (see paragraphs [0010] and [0012] of the patent).

Thus the known potential use of lactose to stabilise lyophilisates does not equate with the specific effect of lactose on tigecycline epimerisation disclosed in the patent, nor does this known optional use justify that the crucial epimerisation problem be disregarded in the assessment of inventive step.