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‘Expectation of Success’ as Part of Inventive Step Analysis

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MyriadThis is the second in a series of articles on biotech inventions (the first article can be found here). The present article discusses ‘expectation of success’ which is often considered as part of assessment of inventive step for biotech inventions and also in other life science areas such as pharmaceuticals. Whilst this article is written from the perspective of how the test is used at the European Patent Office (EPO) and in the UK Courts, ‘expectation of success’ is also applicable in other territories.

Part of biotech research involves empirical testing of whether a given invention will work. For example many compounds have activities, such as inhibiting protein activity, that makes them potential treatments for cancer. However the vast majority will not be effective treatments, and this can only be assessed by testing. Biological systems are too complex to allow prediction of which potential treatments will actually work. Many compounds will turn out to be toxic for example. In any given situation there will be reasons as to why the invention would not have worked. Those reasons can contribute to inventive step analysis as ‘expectation of success’, the lower the expectation of success the higher the chance that the invention is inventive.

Assessment of inventive step of biotech inventions often comes down to two considerations: was it ‘obvious to try?’ based on the prior art, and ‘was there a reasonable expectation of success?’. Often where the relevant techniques have become routine there will be an expectation of success. For example if the invention concerns cloning a species homologue of a known gene there would be an expectation of success given that cloning homologous genes is now routine. However if there were other factors, such as the percentage homology being very low or if there was reason to believe a homologue did not exist in that species, then this would influence expectation of success and potentially make the new gene inventive.

At the EPO inventive step is usually assessed by looking at the step required to reach the invention from a primary prior art reference. From knowledge of the prior art and of European practice it is usually possible to predict how expectation of success will be judged by the Examiner. The relevant part of the ‘EPO Case Law Book’ can be seen here, and provides examples of how the EPO looks at ‘expectation of success’ where gene cloning or mutagenesis techniques are used.

However in certain cases expectation of success can lead to unpredictability and it can also be used to ‘salvage’ inventions that seem very obvious. Any teaching in the prior art which gives reason to assume the invention does not work can become the basis of lack of expectation of success and different Examiners will be influenced by this to different degrees.

In addition the definition of what ‘success’ is can also influence whether something is found to be inventive. Using the example given above, ordinarily there would be an expectation of success in cloning a species homologue. However if the new gene turned out to have an unexpected advantageous property it could be found to be inventive. ‘Success’, i.e. the ‘problem being solved’ as the EPO would say, could then be seen as providing a gene with the advantageous property, rather than merely providing a species homologue. The expectation of success in providing a gene with the advantageous property might be low, for example if few genes are known to have that property. Clearly in this situation which definition of ‘success’ is used will determine whether the new gene is judged to be inventive.

In the UK Courts expectation of success is more complicated. In the recent case Teva v Leo [2014 EWHC 3096 (Pat) Mr Justice Birss said:

‘Obvious to try cases usually involve consideration of the level of expectation of success but one cannot lay down a general characterisation of what the true level of expectation must be in every case beyond stating that it must be a fair one. In that way the differences between different cases is taken into account. It is wrong to ask whether something might achieve a particular desired effect. It is correct to ask whether it was obvious that it would achieve that effect.’

He seems to be saying that it is wrong to think of expectation of success as something one asks before the invention is made, in the form of ‘will this drug work?’, for example. Instead once one sees that the inventions does work, one then asks ‘was it obvious it would have worked?’ given what was known at the priority date.

In this case Birss analysed inventive step by along the lines that would have been taken during the R&D process, and essentially decided the case on whether the skilled person would have ‘proceeded to test’ a solvent that was present in the product of the invention, rather than judging whether the solvent was likely to have worked. In the decision it is not clear how expectation of success contributed, if at all.

The decision in Teva v Leo seems inconsistent with Conor v Angiotech [2008] UKHL 49 which is seen as a pivotal case on inventive step of biotech and pharmaceutical inventions. Here the House of Lords warned against judging inventive step based on whether it would be ‘obvious to test’ a substance, and instead expectation of success should be taken into account.

However it is not straightforward to assess expectation of success in a multi-step R&D process. Any specific candidate compound going through the required tests is more than likely to fail, thought it may have been an obvious candidate to choose to test. Should inventive step be judged based on how likely it was to fail or on how obvious it was to test? The UK Courts seem to follow the latter analysis more often and the outcome very much depends on the facts of the case. So whilst expectation of success is an important consideration for inventive step of biotech inventions at the UK Courts it very difficult to predict exactly how it will contribute to the inventive step determination.

Suleman Ali  24 October 2014 

This is part of a series of articles on biotech inventions by Suleman Ali, a consultant at K2, the network of patent and trade mark attorneys and IP consultants developed by Keltie LLP.


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