10.8. Surprising effect – bonus effect

An effect which may be said to be unexpected can be regarded as an indication of inventive step (T 181/82, OJ 1984, 401). However, certain preconditions have to be met. In T 21/81 (OJ 1983, 15) the board considered that if, having regard to the state of the art, it would already have been obvious for a skilled person to arrive at something falling within the terms of a claim, because an advantageous effect could be expected to result from the combination of the teachings of the prior art documents, such claim lacked inventive step, irrespective of the circumstance that an extra effect (possibly unforeseen) was obtained (see T 365/86, T 350/87, T 226/88, T 1317/13). Similarly, in T 69/83 (OJ 1984, 357), the board held that where, because of an essential part of the technical problem being addressed, the state of the art obliged a skilled person to adopt a certain solution, that solution was not automatically rendered inventive by the fact that it also unexpectedly solved part of the problem. (see also T 231/97). In T 170/06 the board held that if it was obvious for the skilled person to combine prior art teachings in order to solve an essential part of the problem, the presence of even an unexpected extra effect allowing another part of the problem to be solved at the same time did not in principle imply the presence of inventive step.

Furthermore, in T 192/82 (OJ 1984, 415) the board stated that the skilled person had to be free to employ the best means already available for his purposes, although the use of means leading to some expected improvements might well be patentable in relying on an additional effect, provided this involved a choice from a multiplicity of possibilities. The lack of alternatives in this respect might therefore create a "one-way-street" situation leading to predictable advantages which remained obvious in spite of the existence of some unexpected "bonus" effect (see also T 766/92, T 1936/13). The board also pointed out in T 506/92 that an additional effect achieved inevitably by the skilled person on the basis of an obvious measure without any effort on his part simply represented a bonus under EPO case law which could not substantiate inventive step, even as a surprising effect (see also T 431/93, T 681/94, T 985/98, T 794/01, T 688/13, T 179/18). In T 848/94 the solution of the existing technical problem required a combination of measures that was not suggested by the prior art in such a manner that it would have been adopted by the person skilled in the art (see also T 716/07). Therefore, the person skilled in the art was not in a "one-way-situation".

The board in T 936/96 held that, once a realistic technical problem had been defined and once it had been established that a particular solution to such a problem would have been envisaged by a skilled person in the light of the relevant state of the art, that solution could not be said to involve an inventive step, and this assessment was not altered by the fact that the claimed invention inherently also solved further technical problems. In the case in point the claimed surprising effect could not be regarded as an indication of the presence of an inventive step.

In T 227/89 the board stated that in determining which effect was crucial and which was merely accidental (the so-called "bonus effect"), a realistic approach had to be taken, considering the relative technical and practical importance of those effects in the circumstances of a given case (see also T 732/89, T 729/90, T 1147/16). When assessing chemical substances for inventive step, it is often their surprising properties that are considered (see in this connection T 20/83, OJ 1983, 419).

According to the case law of the boards of appeal, an improvement is not a prerequisite for inventive step (see also in this chapter I.D.4.5 "Alternative solution to a known problem"). In T 154/87 it was pointed out that the achievement of a surprising effect was no precondition for the existence of inventive step. All that was necessary was to ascertain that the respective subject-matter could not be derived by the skilled person in an obvious manner from the available prior art (T 426/92, T 164/94, T 960/95, T 524/97, T 888/08).

In T 551/89 the board stated that an effect which was to be expected as the result of an obvious measure could not contribute to recognition of the required inventive step, even if the scale of this effect was surprising to the skilled person. In this case an effect whose scale surpassed the skilled person's hopes merely represented a bonus effect following inevitably from the use of an obvious measure and obtained by the skilled person without any inventive effort on his part (T 506/92, T 882/94).

In T 240/93 the application related to an apparatus for the surgical treatment of tissues by hyperthermia, equipped with heat protection means. The application was refused by the examining division, which considered the short treatment duration of one hour and further advantages resulting from the use of cooling means to be extra (bonus) effects. The board, however, stated that in the case in point the objective problem underlying the invention was to provide an apparatus for the effective therapeutic treatment of benign prostate hyperplasia in a short period of time. In view of the many considerable practical advantages of a single one-hour hyperthermia session for a patient, such a short treatment duration could not be dismissed as a mere "bonus" effect, but was crucial to the invention and the basis of the objective problem.

In T 2015/20 the application stated that it had been surprisingly found that for treatment of respiratory disorders, in particular asthma and COPD, aclidinium was most effective upon administration by inhalation in a dosage of about 400 μg metered nominal dose. D1 described the combination of a M3 muscarinic receptor antagonist such as aclidinium bromide with a PDE4 inhibitor, and described 1-2 formulations comprising 100 μg aclidinium bromide. It did not provide any suggestion towards an optimized dose of 400 μg. D2 presented a short summary of a trial in which patients suffering from COPD were administered a single dose of 100, 300 or 900 μg of aclidinium bromide, but which the board concluded seemed to teach away from an optimised dose of 400 μg for treatment of a chronic disease such as asthma. The board found that the defined subject-matter of claim 1 was not the obvious result of routine experimentation, but rather represented the unexpected outcome of a study and concluded that the subject-matter of claim 1 involved an inventive step.