Wednesday, April 3, 2019

UKSC Weighs in on Obvious to Try and Golden Bonus

Actavis v ICOS [2019] UKSC 15 (27 March 2019) Lord Hodge: Lady Hale, Lords Kerr, Sumption, Briggs aff’g [2017] EWCA Civ 1671 Kitchin LJ: Lewison, Floyd LLJ rev’g [2016] EWHC 1955 (Pat) Birss J
EP (UK) 1,173,181 / tadalafil dosage / CIALIS

In Actavis v ICOS the UKSC has affirmed the decision of the EWCA holding ICOS’s dosage patent for tadalafil to be obvious on an obvious-to-try analysis. As discussed here, the EWCA decision was consistent with the way the obvious-to-try analysis has consistently been applied by the Federal Courts. The decision of the UKSC provides further reassurance, if any was needed, that the Canadian approach is sound. Along the way, the UKSC expressly affirmed the “golden bonus” rule: if a particular invention is obvious for one reason, it does not become non-obvious simply because it had additional unexpected or non-obvious advantages.

The obvious-to-try analysis was endorsed by the SCC in Sanofi 2008 SCC 61, where the Court stated that:

[65] I am of the opinion that the “obvious to try” test will work only where it is very plain or, to use the words of Jacob L.J., more or less self-evident that what is being tested ought to work.

This might lend itself to the view that it must be self-evident, prior to any experimentation, that the claimed invention will solve the problem at hand. But the Court immediately went on to say that for an invention to be “obvious to try”, there must be evidence that it was “more or less self-evident to try to obtain the invention” [66]. That is, it is trying that must be self-evident, not that that the specific claimed invention would work. In Actavis v ICOS, the UKSC addressed exactly this question.

The facts in Actavis v ICOS are simple, and raise a paradigmatic version of the obvious-to-try analysis. The key claim was to a 5mg daily dose of tadalafil for the treatment of ED.* Tadalafil was known to be an effective oral treatment for ED, but the optimal dosage was not part of the the prior art [23]. It was obvious to carry out a dose-ranging student to determine the appropriate dose. The initial dose ranging study would be of on demand dosing using 25, 50 and 100mg doses. This study would have revealed a therapeutic plateau in that range [35]-[36]. Birss J held that it was “very likely” that a skilled team would then investigate lower doses. Both the EWCA and the UKSC treated this “very likely” finding as meaning that it would have been obvious to do so; ie, that it would have been obvious to try lower doses. Birss J held that if they had done so they would have discovered that a 5mg dose tadalafil was efficacious and had reduced side effects; that is, the posita would have discovered the invention. There would, however, have been no prior expectation that a dose of 5mg would have been efficacious; on the contrary, it would have been surprising that such a low dose would be effective [37]. It would have doubly surprising that the 5mg dose also had reduced side-effects [37].

Birss J held that claims at issue to be non-obvious, essentially because “the claimants failed to prove that efficacy at 5mg tadalafil was predictable or worth considering by the skilled team based on the properties of tadalafil as compared to sildenafil,” and “[a]ssuming a 5mg/day dose of tadalafil was tested, it would not be tested with a reasonable expectation of success” [38]. In other words, Birss J held that the 5mg dose was not obvious because, if the skilled team had been asked, prior to testing, whether a 5mg dose would have been efficacious, the answer would have be "probably not". In Birss J's view, the conclusion of non-obviousness followed notwithstanding that the entire course of research leading to the invention would have been obvious to try. The EWCA reversed, and Lilly (the exclusive licensee), appealed.

The key question was summarized in Lilly’s central submission [50]:

the question which the Court of Appeal should have asked was whether at the priority date, before the skilled team embarked on its investigation, it was obvious in the light of [the knowledge that tadalafil is effective for treating ED], and without knowledge of the alleged invention, that a 5mg per day dose of tadalafil would be a safe and effective treatment, with minimal side effects, for sexual dysfunction.

That is, the invention is not obvious unless there would be a reasonable expectation, prior to undertaking the dose-ranging study, that the 5mg dose would work. A reasonable expectation that some minimum dose would be safe and effective, and that the minimum could be determined from a dose-ranging study, would not suffice, unless there was a reasonable expectation that the 5mg dose in particular would work.

The UKSC rejected this submission [52]: “uninventive steps which the skilled team would take after the priority date to implement the [knowledge that tadalafil is effective in treating ED] are not excluded from consideration in assessing the obviousness of the alleged invention at the priority date” [59]. On the facts, the UKSC affirmed the EWCA in holding the patent to be obvious [105]. This is a clear holding that the mere fact that there would be no reasonable prior expectation that the particular claimed invention – the 5mg dose – would work, does not in itself mean the invention is non-obvious.

The UKSC elaborated with nine points.

First, “it is relevant to consider whether at the priority date something was ‘obvious to try’” [65]. I take this to mean the same as the SCC meant in Sanofi when it held at [64] that the “obvious to try” inquiry is one factor to be considered in the obviousness inquiry. An invention which is obvious to try is not necessarily obvious for that reason alone, as there may be invention in getting it to work.

The second point was that “the routine nature of the research and any established practice of following such research through to a particular point may be a relevant consideration” [66]. Even if it was not obvious in advance that the invention would work, it may nonetheless be obvious, if the route to success was obvious to try, and there were no difficulties along the way requiring invention. The Court continued by saying that this is “weighed against the consideration that the claimed process or product was not obvious to try at the outset of a research programme” [66]. This is a bit obscure to me. The point appears to be that the fact that the particular claimed product – the 5mg daily dose – was not obvious to try at the outset is a consideration. I’m not sure why that should be a consideration, as the premise here is that the specific claim product would not have been predicted in advance, even though it was the outcome of a routine investigation.

“Thirdly, the burden and cost of the research programme is relevant” [67]. The parallels the Sanofi factor asking as to the “extent, nature and amount of effort required to achieve the invention? Are routine trials carried out or is the experimentation prolonged and arduous, such that the trials would not be considered routine?” [69] Even trials that are technically routine might nonetheless rise to the level of invention if sufficiently arduous: “A patient searcher is as much entitled to the benefits of a monopoly as someone who hits upon an invention by some lucky chance or an inspiration” (Halocarbon [1979] 2 SCR 929).

“Fourthly, the necessity for and the nature of the value judgments which the skilled team” [68]. Routine work is no longer routine if it requires extensive exercise of judgement.

“Fifthly, the existence of alternative or multiple paths of research will often be an indicator that the invention contained in the claim or claims was not obvious” [69]. Again, this corresponds to Sanofi (by coincidence also at [69]): “Are there a finite number of identified predictable solutions known to persons skilled in the art?”

“Sixthly, the motive of the skilled person is a relevant consideration. The notional skilled person is not assumed to undertake technical trials for the sake of doing so but rather because he or she has some end in mind. It is not sufficient that a skilled person could undertake a particular trial; one may wish to ask whether in the circumstances he or she would be motivated to do so” [70]. The invention may lie in the decision to try a pursue a particular line of investigation, even if the inquiry is routine after that decision is made. Put another way, an invention that is not obvious to try, is not obvious under the obvious to try test. The invention may lie either in the decision to pursue a particular line of inquiry, or in overcoming obstacles along the way.

“Seventhly, the fact that the results of research which the inventor actually carried out are unexpected or surprising is a relevant consideration as it may point to an inventive step, at least in so far as it suggests that a test was not obvious to try or otherwise the absence of a known target of the research which would make it less likely that the skilled person would conduct a test” [71]. I take this to be related to the previous point. Mere unexpected results – as on the facts, the unexpectedly low effective dosage – does not establish non-obviousness, but the unexpected nature of the results may be relevant to the extent that it supports a finding that the inquiry was not obvious to try in the first place.

“Eighthly, the courts have repeatedly emphasised that one must not use hindsight, which includes knowledge of the invention, in addressing the statutory question of obviousness” [72]. This point is very well recognized by the Canadian courts.

The ninth point is particularly significant, as it is the first time, to my knowledge, that the UKSC has expressly affirmed the “golden bonus” rule. If a particular invention is obvious for one reason, it does not become non-obvious simply because it had additional unexpected or non-obvious advantages. The leading case is Hallen & Co v Brabantia (UK) Ltd [1991] RPC 195 (EWCA), in which it was obvious to coat a corkscrew with slippery PTFE in order to aid its penetration into the cork. The EWCA held that the invention did not become non-obvious simply because it turns out that it also had a non-obvious benefit of improving extraction of the cork. That holding has now been approved in principle by the UKSC [73], and also apparently applied it on the facts, as the 5mg dosage had a surprising beneficial property of minimal side effects, which nonetheless did not make that dosage regime an invention [31].

While the UKSC held the claims at issue to be obvious, the Court took pains to say that dosage patents are not suspect per se, approving the view that: “there [is] no policy reason why a novel non-obvious dosage regime, which was the product of expensive and unpredictable research, should not be rewarded with a patent of a Swiss-form claim” [76], [103]. Moreover, there is no general rule “that the product of well-established or routine enquiries cannot be inventive” [103]. 

It should not be very surprising that the SCC and UKSC jurisprudence on obvious-to-try are consistent, given that the SCC in Sanofi relied heavily on the prior UK case law. It is nonetheless reassuring that a consistent body of jurisprudence has developed, as this indicates that the charted path was the right one.

*The representative claim was Claim 7, which was effectively to a dosage form of tadalafil suitable for oral administration up to a maximum total dose of 5 mg per day, for the treatment of sexual dysfunction.


  1. Your analysis of Sanofi focuses on the wording of paragraph 66: “was more or less self-evident to try to obtain the invention”, and I believe you are trying to draw a distinction between that language and the paragraph 65 language: “was more or less self-evident that what was being tested ought to work”.
    However, at paragraph 69 of Sanofi, the Court expressly sets out the factors which are to operate in an “obvious to try” scenario. The first of these, paragraph 69.1, states:
    “1. Is it more or less self-evident that what is being tried ought to work?”
    Moreover, this same requirement is repeated at paragraph 83 of the decision and was the test adopted when the court evaluated obviousness (paragraphs 84 and 85).

  2. Yes, quite right, there are several statements to that effect in Sanofi, and I would not have been surprised to see the courts interpret it in the same way Birss J did. But on the whole, reading Sanofi in light of the case law it cites, I think the better interpretation is that it says the same thing as the UKSC. I would say that the SCC left both doors open on this point, though we might debate which door was open wider. Since then, the FC/FCA has consistently interpreted obvious-to-try in the same way as the UKSC has now adopted. I also think that interpretation is sound in principle and consistent with Sanofi, though perhaps not compelled by it. So both doors were open, and the courts have chosen the right one.