Eli Lilly Canada Inc v Apotex Inc 2023 FCA 125 Rivoalen JA: de Montigny, Gleason JJA
affg 2020 FC 816 St-Louis J
2,371,684 / tadalafil / CIALIS ADCIRCA / FC Selection / FC Anticipation
This case is ultimately a straightforward example of the asserted claims being invalid on
an obvious-to-try analysis, but because of the way it was argued it also sheds some light
on the role of the inventive concept in the obviousness analysis.
The asserted claims of the 684 patent are to dosage forms of tadalafil for treating ED,
namely doses from 1 to about 20 mg, as well as specific doses within that range,
including 2.5, 5, 10 and 20 mg doses [FC 197-213]. The question in this case was whether
the 684 patent is valid over the prior art 2,226,784 patent, which claims tadalafil for the
treatment of ED, and disclosed a dose range from 0.2 to 400 mg [12]. At trial, St-Louis J
held on the facts that starting from the knowledge that doses from .02 to 400 mg were
useful, it would be routine for the skilled team to carry out the trials necessary to narrow
that down to the range providing the best balance between efficacy, and safety and
tolerability, and they would be motivated to do so [FC 325–28]. The claimed invention
was therefore obvious to try [FC 323, 330]. The FCA has now affirmed on that basis
[65]–[80].
Lilly’s challenge on appeal was to find a question of law to attack in St-Louis J’s
essentially factual finding. Lilly argued that St-Louis J had erred in her construction of
the inventive concept, a question of law [48] arising at step 3 of the Windsurfing test for
obviousness, which was adopted in Sanofi 2008 SCC 61 [67]. Lilly waffled in its
argument as to what constituted the specific inventive concept, before settling on the
position that the inventive concept is that the claimed dose remains effective in treating
ED, with a reduced flushing side-effect as compared to larger doses of tadalafil
[20]–[27], [61]. (As an aside, getting an extra four years of exclusivity on a popular drug
on the basis of reduced flushing would be grist for the mill for critics of evergreening
practices. From a PR perspective, it is probably a good thing for Lilly that this patent was
invalidated.)
There has been a debate as to the role of inventive concept in assessing obviousness,
which came to the fore in Shire 2021 FCA 52. One central issue is whether the inventive
concept is the “end point” of the obviousness inquiry (Shire [65]), or is rather a
“distraction” that can be avoided if it is unhelpful Ciba 2017 FCA 225 [76]–[77]: see
here. Rivoalen JA held that in this case, it did not matter whether Lilly was right as to
the nature of the inventive concept; the claims were invalid for obviousness in any event
[49].
As noted, St-Louis J used an obvious-to-try analysis, which was endorsed by Rivoalen
JA [65]. (So far as I can tell, Lilly did not dispute that the obvious-to-try test was
appropriate.) St-Louis J found that carrying out a drug dosing study is typically done in
Phase II clinical trials, and it is normally routine work [FC 325]. Such studies aim to
identify the dosage that provides the best balance of efficacy, safety and tolerability [69].
In reviewing the factors relevant to an obvious-to-try analysis, Rivoalen JA pointed out
that the reduced flushing that was eventually identified as an advantage of the optimal
dose does not change the aim of identifying the dose range that offers the best balance
[72]. Further, on the facts that the dosing study in this case was routine; again, this
conclusion is not affected by the fact that reduced flushing turned out to be one of the
advantages of the optimal dose [73]–[77]. After carrying out this routine dosing study,
the skilled person would be motivated to identify and commercialize the optimal dose
[79]. Consequently, the claimed dosage range was obvious [80].
To summarize, there was nothing
inventive about carrying out the dosing study and
identifying the optimal dose—and that conclusion does not depend on the
precise
properties of the final dose. While minimizing the flushing side effect
was one goal of the
dosing study, it is possible that the optimal dose would not have
reduced flushing
significantly; while flushing was a side effect of interest, it is a
relatively minor side-effect, certainly compared to other side-effects
such as passing out from low blood
pressure. So, before carrying out the trials, the skilled person might
not have predicted
that the optimal dose would have reduced flushing. Nonetheless, there
was nothing
inventive about the dosing studies, even though not all the specific
properties of the
optimal dose could not have been predicted ex ante. This is really the
whole point of the
obvious-to-try analysis: when something is obvious to try (finding the
optimal dose) and
the trials themselves are routine, the resulting product is obvious,
even if not all of its
properties could have been predicted in advance.
In other words, apart from the distraction of the inventive concept debate, this was a
perfectly ordinary application of the obvious-to-try test, and the patent was invalidated
on that basis both at trial and on appeal.
What does this tell us about the role of the inventive concept? Rivoalen JA was very
explicit that she was accepting Lilly’s construction of the inventive concept only for the
sake of argument, and her conclusion did not turn on whether that was the true
inventive concept [49], [61]. On its face, this implies that it is not always necessary to
identify the inventive concept in order to assess obviousness.
But there is also a debate as to how to define the inventive concept. In this case, Lilly
seemed to be using it to mean new information that was disclosed in the patent and
embodied in the claimed subject-matter. But the inventive concept has also been
equated to “the solution taught by the patent” (Bristol-Myers 2017 FCA 76 [65]). In a
previous post, I argued that the focus on the obviousness inquiry should be on whether
the subject-matter defined by the claim is the solution to the objective problem that
would have faced the skilled person. This is consistent with Rivoalen JA’s analysis in this
case. In a dosage study, the problem is to find the dose that best balances efficacy
against side-effects. In this case, the solution to that problem was a dose from 1 to about
20 mg. On the facts, that solution was obvious on an obvious-to-try analysis.
So perhaps the underlying issue is how to define the inventive concept. If we define it as
the solution to the objective problem, then perhaps it is the proper focus of the
obviousness inquiry; that view is at least consistent with the result and analysis in this
case. On that view, the real lesson of this case is that if we are going to use the inventive
concept as part of the obviousness analysis, we cannot allow the patentee free rein in
defining it.
Finally, St-Louis J had also held that that the 684 patent was anticipated by the prior art
784, and she had an extended discussion of whether the 684 patent was a selection
patent, evidently on the view that this had important consequences for validity. I had
criticized her analysis of both these points: see here and here. In light of her holding that
the patent was invalid for obviousness, Rivoalen JA found it unnecessary to address
these issues; she added that “[t]hese reasons, however, should not be viewed as
endorsing the Judge’s findings or reasons in respect of these issues” [82].