The Court of Appeal has confirmed that two Genentech patents concerning lyophilised formulations of trastuzumab (the active ingredient in Herceptin) are invalid for obviousness. It also confirmed that a finding of obviousness does not require, in every case, that the skilled person "would" have arrived at the claimed invention without inventive effort.

Giving the leading judgment, Lord Justice Floyd took the opportunity to provide a succinct summary of the law regarding inventive step and the place of the 'obvious to try' doctrine within it.

The law regarding inventive step

Floyd LJ made clear that there is only one statutory question, namely, whether the invention was obvious at the priority date.

Asking whether the invention was "obvious to try" is not a substitute test for obviousness, merely one of many considerations which it may be appropriate for the court to take into account in addressing the statutory question. In any case, it must be coupled with a reasonable or fair prospect (or expectation) of success.

There is no single standard of what amounts to a fair expectation of success. How much of an expectation is needed depends upon the facts of the case. Jacob LJ's statement in Saint Gobain v Fusion-Provida [2005] EWCA Civ 177 that it must be "more-or-less self-evidence that what is being tested ought to work" is, said Floyd LJ, "far from being a test of universal application".

A finding of obviousness also does not require in every case that the skilled person, acting only on the basis of the prior art and his common general knowledge, "would" have arrived at the claimed invention. A "would" test, said Floyd LJ, can be misleading as it is liable to bring in irrelevant considerations, such as whether it would be worthwhile commercialising an otherwise technically obvious product. Such a test would also place another straightjacket on the law of obviousness.

In practice, the skilled person may be faced with a range of obvious possibilities, making it statistically unlikely that he will settle on any of them, but they will all be obvious:

In an empirical field it will...seldom be possible to predict in advance that any individual experiment will work. In many cases, the fact that a routine screening exercise could be carried out will be inadequate to establish obviousness. Nevertheless, on the facts of an individual case ... the team may have a reasonable degree of confidence that a series of experiments will produce some which will work. To impose a requirement that the skilled team must be able to predict in advance which would be the successful combinations is wholly unrealistic. It would lead to the grant of patents for a whole variety of combinations which in fact involved no inventive effort.

However, Floyd LJ indicated that "could" is a minimum condition. He also noted that the Pozzoli decision ([2007] EWCA Civ 588) continues to provide a useful structured approach for judges and tribunals assessing obviousness.

Genentech's appeal dismissed

At first instance, Birss J concluded that the differences between the claimed invention and the prior art ("Carter") "were the result of nothing more than the application of routine screening techniques to common general knowledge excipients" by the motivated skilled team. Birss J's first instance decision of 21 November 2014 is discussed here.

Floyd LJ noted that the judge was well placed to form an impression of the degree of interest in trastuzumab by the time it was known that phase II clinical trials were under way and it was open to him, upon the evidence, to reach the conclusions that he had reached as to the skilled person's motivation to start developing a lyophilised formulation.

Genentech argued that the fact that the claimed excipients would each be on a list of eight or so excipients in each class which could be made the basis of screening experiments went nowhere towards establishing that there was a fair or reasonable expectation of success, but the Court of Appeal was not persuaded by this.

The Court of Appeal also supported the judge's consideration of whether the outcome of the project was what the skilled team would have expected. Rejecting Genentech's submissions that this looked at matters the wrong way around, Floyd LJ said:

If, at the outcome of the project, the skilled team would not be surprised by the result, that is further confirmation of what their expectation had is clear that the judge's assessment was that the skilled team had an ex ante fair expectation of success.

Floyd LJ also distinguished the present case from the Teva v Leo case, which we have previously examined. In that case, Sir Robin Jacob quoted from his own judgment in Saint Gobain and concluded that, in the empirical field in question, in which testing was entirely routine, the claimed invention would only be obvious if the prospect of success with the relevant candidate raised it over and above other candidates.

However, Sir Robin Jacob had noted that "it was not even proved that there was a good expectation that if you did try 20 [non-aqueous solvents] one of them would work", and Floyd LJ considered the facts of the present case to be rather different.

Birss J had made no error of principle.

The Court of Appeal's decision of 27 July 2016 ([2016] EWCA Civ 780) is available here.


This case could be seen as putting Jacob LJ's commentary in St Gobain slightly to one side, and the Court of Appeal's decision in Teva v Leo (now from Sir Robin Jacob) in the 'on its facts' box. Floyd LJ & Kitchin LJ are perhaps looking to take a firmer line on inventive step than Jacob LJ indicated he was willing to consider.

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