‘Bonus’ effect under EPO practice

The Guidelines for Examination at the EPO state that the presence of inventive step may be denied despite evidence of an unexpected technical effect: if the effect is dubbed as a ‘bonus’ effect, it may be disregarded in the assessment of inventive step.  Specifically, according to the Guidelines (G-VII, 10.2):

“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, for example because a lack of alternatives created a "one-way street" situation, the unexpected effect is merely a bonus effect which does not make the claimed subject-matter inventive”

This blog post looks at selected decisions in the chemical field applying the case law on ‘bonus’ effects.

T 713/23

In a recent decision (T 713/23), the Board walked through the criteria that had to be satisfied for a ‘bonus’ effect argument to be successful.

Claim 1 defined a liquid laundry detergent comprising, inter alia, a defined weight percentage of a second polymer, the second polymer being a cellulosic polymer.

The presence of the cellulosic polymer was the distinguishing feature over the closest prior art, and, based on the data in the patent, the objective technical problem was defined as the provision of a laundry detergent composition capable of improving the softness of the treated fabric.

The closest prior art disclosed numerous ‘cleaning polymers’, inc. carboxymethylcellulose.  Similarly, another document on file disclosed various polymers (inc. cellulosic polymers) for use in liquid laundry detergent compositions.

That said, none of the cited documents taught the use of cellulosic polymers as softeners.  The technical effect relied upon was unexpected, and so the patentee’s narrative was very fitting for the EPO’s problem-solution approach.  Inventive step was duly acknowledged.

The appellant argued that it would have been obvious to add a cellulosic polymer as a cleaning agent, and that the obtained improved softness was a mere bonus effect.

The Board explained that, for an unexpected effect to be disregarded as a ‘bonus’ effect, certain conditions had to be met; either:

1)            the situation was characterised by a lack of alternatives as regards the means for achieving the first, expected effect, in the present case the cleaning properties (claim 1 defines a ‘laundry detergent’), such as in a "one-way-street" situation; or that

2)            considering the relative technical and practical importance of the effects in the circumstances of the case, the additional unexpected effect was merely accidental

The Board considered that condition 1 was not met; the cited documents described “a long list of possibilities […], making it clear that a cellulosic polymer represents only one option among many”.  In other words, there was no ‘lack of alternatives’.

Condition 2 was not met either, in the Board’s view - achieving improved softening “was the central problem and objective of the contested patent”, and improvements in fabric softness were therefore “at least as important as any cleaning effect, which was not even addressed in the patent*”.  Improvements in fabric softness could not thus be dismissed as merely accidental.

The claim was thus found to be inventive.

*given that claim 1 defines a ‘laundry detergent’, it seems that the Board meant that the patent and its examples did not explicitly focus on the ‘laundry detergent’ properties per se; i.e. how well the compositions cleaned the fabric.

T 1317/13

In T 1317/13 (a slightly older decision), the claimed invention was found obvious with reference to the ‘bonus’ effect case law.

Claim 1 before the Board was directed to a specific human IL-1 beta binding antibody for use in the treatment of gout.

The closest prior art taught that gout could be treated by blocking IL-1 beta, while another (supplementary) document taught compounds suitable for blocking IL-1 beta in patients suffering from auto-inflammatory syndromes, including an antibody according to claim 1 in suit.  On that basis, the Board considered that it would have been obvious to use the specific antibody for the treatment of gout.

There were two further technical effects (improvements) relied upon by the applicant, but those were also found to have been derivable from the combination of the cited documents; in particular, the supplementary document contained some experimental data pertaining to those effects.

Importantly, the applicant also argued that there was one further relevant technical effect not foreshadowed in any of the cited documents.  The effect was allegedly supported by the post-filed data.  According to the applicant, the effect would not have been expected by the skilled person and thus inventive step should have been acknowledged.

The Board said that, in the present case, it would have already been obvious to implement the administration of the specific antibody for the treatment of gout, and that the fact that there was one further (possibly unexpected) technical effect did not contribute to non-obviousness of the claimed treatment.

Notably, the applicant tried to argue that the ‘bonus’ effect case law applied when there was effectively a ‘one-way-street’ situation (i.e. not in the present case); according to the applicant, such a situation arose where the skilled person was ‘inevitably guided towards a particular destination, such that any surprising effects would be a 'bonus' which would have been achieved anyway’.

The Board essentially said that the situation described by the applicant was not a prerequisite for applying the ‘bonus’ effect case law; it was enough that it would have been obvious to arrive at something falling within the terms of the claim, because an advantageous effect was expected to result from the combination of teachings of the prior art documents.

T 1357/21

Further guidance on the concept of the ‘bonus’ effect can be found in T 1357/21.

Claim 1 was generally directed to a pharmaceutical formulation comprising insulin glargine at a defined concentration.

The distinguishing feature was a higher concentration of insulin glargine (100 U/mL in the CPA and 270-330 U/mL in claim 1).

The patent explicitly mentioned two technical effects vis-à-vis the closest prior art: (1) reduced discomfort or pain upon injection and (2) flatter PK/PD profile and longer duration of action.

Effect (1) was due to the increased concentration of the active substance – this enabled reducing the volume of the injection, which in turn provided for reduced discomfort.  There was also data supporting effect (2) in the patent.

The opponent argued that effect (1) was the ‘main’ technical effect.  It would have been obvious to increase the concentration of insulin glargine to reduce the volume of the injection and hence reduce patients’ discomfort; in this way, effect (2) would have been inevitably achieved; it would have constituted a mere ‘bonus’ effect.

The Board recalled that “an additional effect achieved inevitably by the skilled person on the basis of an obvious measure without any effort on his part simply represents a bonus under EPO case law which cannot substantiate inventive step, even as a surprising effect”.

The Board then noted that the case law on bonus effects could not be applied to all cases where a differentiating feature led to two separable technical effects.  According to the Board, it had to be shown either that there was a lack of alternatives in the context of achieving the first, ‘expected’ improvement or that the unexpected effect was accidental.

The Board said that for situations which would not qualify as a ‘one-way-street’, it would not be appropriate to disregard a crucial and unexpected technical advantage as soon as any additional ‘obvious’ effects were mentioned in the patent.

With reference to T 1317/13 (discussed above), the Board acknowledged that the presence of a ‘one-way street situation’ was not a mandatory prerequisite for the existence of a ‘bonus effect’.  However, the Board also said that the relevant case law did not teach “an unqualified application of the bonus effect case law to any situation of plurality of technical effects without regard to their respective technical and practical importance”.  The fact that two technical effects arose from the same distinguishing feature did not mean that one of the two effects must necessarily be regarded as a bonus effect.

The present case was, in the Board’s view, not a ‘one-way-street’ situation: the skilled person could have addressed the issue of discomfort upon the injection by many other means.  In addition, the effects of flatter PK/PD profiles and longer duration of action were considered to be “essential properties of basal insulins” (i.e. technically relevant and at least as relevant as the reduced discomfort upon injection), and there was evidence on file to support this.

Finally, the Board was ‘not convinced’ that the effect of reduced discomfort should be regarded as a ‘bonus’ effect either (i.e. assuming effect (2) was taken as the ‘primary’ effect) but they did not provide any specific reasoning or conclusion on this point.

T 295/22

Yet another decision is T 295/22, wherein the distinguishing feature resided merely in the mode of administration (oral) of apremilast.  The closest prior art described oral administration amongst a few different possible modes of administration.  In addition, a number of technical effects was substantiated in the patent; those generally related to certain advantageous properties of apremilast in the context of oral administration.

The claim was found to be obvious.  In particular, the Board considered that the reasonable expectation that oral administration of apremilast resulted in a safe and well-tolerated treatment prevailed over the unexpected technical effects relied upon by the patentee.  The Board also relied on the apparent motivation of the skilled person to find ways of administering the particular class of compounds encompassing apremilast orally.

Specifically, at the priority date of the patent, it was known that oral administration of that particular class of compounds was challenging and was associated with side effects.  In the present case, the Board noted that that those challenges would have motivated the skilled person to seek the oral administration and that oral administration would have typically represented the first choice for systemic delivery of a pharmaceutically active agents because of the ease of administration.  There was also evidence on file that oral administration of other compounds from that particular class was ongoing and promising.  The Board also said that there was no prejudice against doing so.

The Board acknowledged the approach adopted in T 1357/21 (discussed above), noting that the case law on bonus effects was not applicable to any situation of a plurality of technical effects, without regard to their respective technical and practical importance.  In the present case, the Board found that since the skilled person would have expected the oral administration to be safe and well-tolerated (i.e. it would have been obvious to arrive at the subject matter of claim 1), it was irrelevant that some additional (potentially unexpected) technical effects could be obtained.

T 1065/18

Another decision concerning the concept of the ‘bonus’ effect is T 1065/18, wherein the objective technical problem was to provide a polymorph of febuxostat which was non-hygroscopic and had higher solubility.

The opponent argued that the skilled person faced with this problem would have been motivated to check whether the polymorphic form of the closest prior art underwent a transition into a new, higher-melting form at higher temperatures (a form having a higher solubility below the transition temperature).

After considering detailed technical arguments, the Board held that by performing a DSC analysis of the form of the closest prior art, the skilled person aiming at higher solubility would have identified the claimed form as being the desired form, i.e. a higher-melting form that results from the prior art form by an endothermic phase transition at higher temperatures.  The Board then said that, given this reasoning, the effect relating to hygroscopicity could be considered merely as a bonus effect that the skilled person inevitably achieved because they were primarily looking for a crystalline form of febuxostat with higher solubility.

Conclusion

The ‘bonus’ effect doctrine appears to arise only rarely in the chemical field.  It seems difficult to successfully rely on such an argument as an opponent: inventive step assessment is rarely characterized by situations where there is a lack of alternative options for achieving an effect, and technical effects in the chemical field are rather unlikely to be disregarded as accidental.  Furthermore, as shown by at least T 295/22, the assessment remains highly fact-dependent.

If you have any questions about EPO practice, feel free to get in touch.  

This article is for general information only and is not intended to constitute legal advice. If you would like tailored advice on a specific matter, please do not hesitate to contact me.