The Inventive Concept as the Focus of the Obviousness Analysis

Hoffman-La Roche Ltd v Apotex Inc / valganciclovir (NOC) 2013 FC 718, Kane J
            2,154,721 VALCYTE

Yesterday’s post discussed anticipation. This post discusses obviousness, which was the other main validity issue. Ultimately, obviousness turned largely on the facts, but the analysis raised an important question as to whether the focus of the obviousness inquiry should be the invention as claimed, the inventive concept of the specification, or the inventive concept of the individual claims.

Valganciclovir is the mono-L-valine ester of ganciclovir [32]. Ganciclovir is an antiviral nucleoside which effective in the treatment of certain herpes viruses [4]. Acyclovir is another antiviral nucleoside which effective in the treatment of certain herpes viruses. Both acyclovir and ganciclovir suffered from poor bioavailability when taken orally. In the prior art the L-valyl ester of acyclovir, valaciclovir, was the acyclovir prodrug with the best oral bioavailability. (As I understand it, an “L-valyl” ester and an “L-valine” ester are the same.) The question was whether the good bioavailability of the L-valyl ester of acyclovir made it obvious to develop the same ester of ganciclovir in order to improve bioavailability. Kane J held it did. This conclusion turned largely on the facts.

Because this is a field in which prediction is difficult, the obvious to try test was invoked. Roche argued that for an invention to be obvious to try “the skilled researcher must know or must predict with almost certainty before carrying out any experiments that the invention claimed ‘ought to work’. The mere possibility that something might turn up is not enough.” [309]. In my view this is wrong. The point of the obvious to try is test is that “[i]n areas of endeavour where advances are often won by experimentation" (Sanofi 2008 SCC 61, [68])  predicting the outcome of experiments with certainty is not possible. If prediction with certainty were the test, then no inventions would be obvious in such fields. But that cannot be right, because there are some cases where it is obvious to try a particular approach, and that approach does in fact work when tried; in such cases, the invention is obvious, even if the success could not have been predicted with certainty beforehand. Roche’s position is no doubt inspired by the statement in Sanofi 2008 SCC 61 that

For a finding that an invention was “obvious to try”, there must be evidence to convince a judge on a balance of probabilities that it was more or less self-evident to try to obtain the invention. Mere possibility that something might turn up is not enough [66].

But that is with respect to whether it is obvious to try, not whether it is obvious that the attempt will be successful. Apotex’s position is a more accurate reflection of the law: “there is no requirement that the skilled person 'know' the result of the experiment before it is undertaken; only a fair expectation of success is required” [320]. (Though even if there is a fair expectation of success, the invention may nonetheless be non-obvious if there are unexpected hurdles to be overcome in achieving that success.)

Kane J seems not to have picked between these positions. Instead, she seems to have held that the invention was obvious even on Roche’s standard: “it would have been more or less self-evident that adding the mono-L-valine ester to ganciclovir would also result in increased bioavailability over ganciclovir” [340], and “it was self-evident that it ought to work based on the acyclovir research and on the prior art” [353]. If that is so, then a fortiori the invention is obvious on the test as stated by Apotex.

This is all reasonably straightforward. What is more noteworthy about Kane J's analysis is that it did not follow the Windsurfing / Pozzoli approach to obviousness approved by the SCC in Sanofi [67]. In particular, the second step is “Identify the inventive concept of the claim in question or if that cannot readily be done, construe it.” In this case, Kane J focused entirely on the inventive concept, notwithstanding that identification of the inventive concept “is a point of major disagreement between the parties” [99]. In Windsurfing [1985] RPC 59 (CA) itself, the second step was identification of “the inventive concept embodied in the patent in suit.” Pozzoli [2007] EWCA Civ 588 [23] modified this step to “Identify the inventive concept of the claim in question or if that cannot readily be done, construe it” (my emphasis). The reason for this modification, as Jacob LJ explained in Pozzoli is that identification of the inventive concept “can develop into an unnecessary satellite debate” and in such cases “the sensible way to proceed is to forget it and simply to work on the features of the claim.” Kane J acknowledged this advice [268] (though she mistakenly attributed it to Lewison J, who was the trial judge in Pozzoli), but rather than following it, she chose to focus on the inventive concept, saying its identification “is essential for the assessment of all the allegations and it should therefore be addressed at the outset” [99].

Roche argued that the inventive concept was improved bioavailability valganciclovir over the prior art esters of ganciclovir [100]. Apotex argued that the inventive concept was the crystalline form of valganciclovir [104], which was claimed separately in Claim 4. Kane J concluded that the inventive concept was “valganciclovir, a stable prodrug with low toxicity and improved oral bioavailability over ganciclovir” [132]. This does not coincide with the position of either party; Kane J specifically held that the inventive concept was improved bioavailability over ganciclovir, not over the prior art esters [126], [132]. The prior art includes EP 329, which, as discussed in yesterday’s post, disclosed esters with improved bioavailability over ganciclovir. This analysis raises two issues: (1) the focus on the inventive concept of the specification, rather than the claims; and (2) comparing the inventive concept with the genciclovir, rather than with the state of the art.

To begin with this second point, this analysis is contrary to s 28.3 of the Act, which provides that the subject matter defined by the claim is to be assessed in light of the state of the art (s 28.3(a), (b)). Kane J determined the inventive concept by an analysis of the specification: she stated that “Based on my review of the Patent and of the views of the experts, I find that the ‘721 Patent does not assert that the invention is an improvement over the bis-ester (EP 329) and other prior art but only over ganciclovir,” and “The Patent does not assert that the invention is an improvement over the bis-ester (EP 329) and other prior art but only that it is an improvement over ganciclovir” [123], [124], and see also [126], [167], [168]. The effect of this analysis is to render the obviousness analysis subjective, which is to say that obviousness will turn on the inventive concept as understood by the inventor. By specifying that the question is whether the invention is obvious in light of the state of the art, s 28.3 establishes that the obviousness inquiry is objective. This means that when the inventor is mistaken as to the true nature of the technical advance, obviousness will be assessed in light of the true contribution, not the contribution understood by the inventor. Suppose valganciclovir was obvious in light of EP 329, which disclosed esters with improved bioavailability, but not in light of ganciclovir alone. If that were the case, that the patent asserted the invention was improved bioavailability over ganciclovir would not save it; the question is whether the true inventive contribution - improved bioavailability over the EP 329 esters - was obvious, not whether the contribution the inventors thought they had made was obvious. On the facts, it seems that no harm was done. The state of the art, which included EP 329, was more advanced than ganciclovir, and the risk in asking the wrong question is that Kane J might have found the invention to be non-obvious over ganciclovir, even though it might have been obvious over EP 329 which disclosed significant progress in bioavailability. Given that she actually concluded that valganciclovir was obvious over ganciclovir, it would necessarily follow that it was obvious over the state of the art.

The first point, the focus on the inventive concept, raises similar problems. Section s 28.3 provides that it is “[t]he subject-matter defined by a claim” that is the focus of the obviousness inquiry. Section 58 provides that claims stand or fall independently. It is normal that a patent will have broad claims and narrower claims, and the effect of these provisions together is that if the broader claims are invalid as being obvious, the patentee may nonetheless rely on the narrower claims, which must be assessed independently for obviousness. Again, this is important when the patentee is mistaken as to the true nature of its contribution, thinking it had contributed a broad new class of compounds, when in fact it had only contributed a sub-class or an individual compound. The effect of the focus on the inventive concept as understood by the patentee, rather than the invention as claimed, is that if the inventor is mistaken as to the inventive concept, and the inventive concept as understood by the inventor is obvious, then all the claims will be invalid without an independent obviousness inquiry, contrary to s 28.3 and s 58. This appears to have happened in this case. The ‘721 patent claimed both valganciclovir (Claim 1) and valganciclovir in the crystalline form (Claim 4). Kane J held that the improved bioavailability of valganciclovir was obvious, and she consequently held all the claims to be invalid for obviousness, without an independent inquiry as to whether the crystalline form was inventive [354]. This is not necessarily a flaw in decision. Roche argued that the inventive concept was improved bioavailability – it was Apotex that argued it was the crystalline form – so it is entirely possible that Roche did not advance any independent argument as to non-obviousness of the crystalline form. In general, however, this approach may lead to error. The problem is not the focus on the inventive concept rather than the claims; in the case of a chemical compound claim in particular, it is normally identification of the properties of the compound which provide the inventive contribution, and so it is necessary to look to the specification to identify the inventive concept. The problem lies in the focus on the inventive concept of the specification as a whole, as opposed to inventive concept of the subject matter defined by the claims. As Jacob J has pointed out, “It is the ‘inventive concept’ of the claim in question which must be considered, not some generalised concept to be derived from the specification as a whole. Different claims can, and generally will, have different inventive concepts” Unilever v Chefaro [1994] RPC 567, 580 (Pat).