One of the joys of blogging is that commenters, as well as alerting the hapless blogger to typographical errors and terminological infelicities, can alert to interesting aspects of a decision that did not seem striking at a first review.
So it was with the case of the appeal decision Hospira v Genentech  EWCA Civ 780, which, when this Kat first reviewed it, seemed to be a fairly straightforward case of the first instance judgment being affirmed on appeal – no, the judge did not make any error of principle, appeal dismissed, move on. However, as the comments on the original post showed, in fact there is an interesting discussion of the law of obviousness that basically says that each case turns on its own facts, because the evaluation of obviousness involves a multi-factorial assessment in order to answer the sole statutory question – whether the invention was obvious at the priority date.
This is emphasised in a number of earlier cases referred to in the judgment, such as Generics (UK) Ltd v H. Lundbeck A/S  EWHC 1040 (Pat) (reported by the IPKat here):
"The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success."
One consideration, which nevertheless does not replace the statutory question, is whether the invention was “obvious to try”, which must however be coupled with a “reasonable or fair prospect of success” (mirroring the EPO test of T 60/89). In relation to this last point, however, the question arises, what is “success” and how strong must the prospect of success be? One way of putting this is whether the skilled person “would”, rather than “could”, arrive at the claimed invention without inventive effort (mirroring the EPO test of T2/83), but Lord Justice Floyd (delivering the Court of Appeal decision with which Lord Justice Kitchin and Lord Justice David Richards agreed) stated that this dichotomy can be misleading, as it may bring in non-technical considerations that are not relevant.
Furthermore, “success” does not necessarily entail arriving at the precise combination claimed: Floyd LJ further stated:
“I would however not accept … that it must be established in every case that the skilled person would necessarily have arrived at the precise combination claimed. That would be to place another straitjacket on the law of obviousness. The skilled person may be faced with a range of obvious possibilities, making it statistically unlikely that he will settle on any one of them. They will all be obvious.”
Earlier cases referred to in the judgment have emphasised that the “obvious to try” test itself requires the consideration of many factors. As stated by Kitchin LJ in Medimmune Ltd v Novartis Pharmaceuticals UK Ltd  EWCA Civ 1234:
"Whether a route has a reasonable or fair prospect of success will depend upon all the circumstances including an ability rationally to predict a successful outcome, how long the project may take, the extent to which the field is unexplored, the complexity or otherwise of any necessary experiments, whether such experiments can be performed by routine means and whether the skilled person will have to make a series of correct decisions along the way."
While Jacob LJ in Saint Gobain PAM SA v Fusion-Provida Ltd  EWCA Civ 177 (Katpost) articulated a test that appeared to be rather general – it must be "more-or-less self-evident that what is being tested ought to work", Floyd LJ has now clarified that this “is far from being a test of universal application”, quoting with approval the warning of Kitchin LJ in Novartis AG v Generics (UK) Ltd  EWCA Civ 1623 (Katpost) against imposing a straitjacket on the law by adopting any form of words as a standard:
"What is a reasonable or fair expectation of success will again depend upon all the circumstances and will vary from case to case. Sometimes, as in Saint Gobain, it may be appropriate to consider whether it is more or less self-evident that what is being tested ought to work. So, as this court explained in that case, simply including something in a research project in the hope that something might turn up is unlikely to be enough. But I reject the submission that the court can only make a finding of obviousness where it is manifest that the test ought to work. That would be to impose a straitjacket on the assessment of obviousness which is not warranted by the statutory test and would, for example, preclude a finding of obviousness in the case where the results of an entirely routine test are unpredictable."
The patent that was found to be obvious in the present case [EP 1 516 628] claims a lyophilised formulation of trastuzumab with three excipients – histidine as a buffer, Tween 20 as a surfactant and trehalose as a lyoprotectant. The judge at first instance considered that each of those was an obvious candidate for the respective function and would be in the first or second tier of candidates to be tried. He therefore considered that the claimed invention was an obvious result of using standard screening methods, using routine approaches applied to excipients which were part of the common general knowledge, even though the skilled person would not know at the outset that the formulation arrived at would be that consisting of polysorbate 20, histidine and trehalose. The Court of Appeal confirmed this ruling of Mr Justice Birss, and noted that at the beginning of the project the skilled team would expect to be able to produce promising candidates, while at the end of the project, the skilled team would not be surprised by the result, so that the skilled team had ex ante a fair expectation of success of the project overall.
The situation under consideration was distinguished from that in Teva v Leo  EWCA Civ 779 (Katpost) where Sir Robin Jacob in the Court of Appeal overturned a finding of obviousness by Birss J at first instance, upholding the validity of another pharmaceutical formulation patent. In that case, “it was far from established that any non-aqueous non-toxic solvent would produce a stable ointment”, and “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 so there was no reasonable expectation of success.
The insistence on the statutory question as the sole standard for assessing obviousness is welcome as a matter of law, but the multi-factorial and fact-dependent nature of the assessment must make it difficult to predict how an English court will judge the validity of a patent.