Monday, May 22, 2023

Sufficiency, Overbreadth, or Utility?

Eli Lilly Canada Inc v Teva Canada Limited 2022 FC 1398 St-Louis J

2,226,784 / tadalafil / CIALIS / NOC

I’m back to blogging again after an end of term vacation—still catching up on the backlog from my longer hiatus over the winter. In my last post on this case I discussed the meaning of “or”. This post turns to validity. St-Louis J held the 784 patent to be invalid for overbreadth [120] and insufficiency [149], while declining to address utility. I have argued that overbreadth is almost always functionally duplicative of another established ground of invalidity, and this case illustrates that point once again, as the facts supporting the finding of overbreadth were the same as those supporting insufficiency.

The facts are reasonably straightforward. The 784 patent relates to the use of tadalafil for the treatment of ED. Claim 2, which is representative for present purposes, is to a pharmaceutical composition for the treatment of ED in a male animal, comprising “[tadalafil] or a physiologically acceptable salt or solvate thereof.” All asserted claims include the phrase “or a physiologically acceptable salt.”

St-Louis J found on the facts that it is not possible to make a physiologically acceptable salt of tadalafil [118]. Tadalafil does not have an ionisable functional group and consequently it is very difficult to make a salt form [103]. It may be possible to make one or two salts, but only under extreme conditions that would result in the degradation of the tadalafil such that the resultant salt would not be sufficiently pure and stable to be considered physiologically acceptable [118]. As a result, St-Louis J held the 784 patent to be invalid for overbreadth [120] and insufficiency [149], while declining to address utility.

As discussed in my last post, St-Louis J concluded that a physiologically acceptable salt is an essential element of the claim. While I have my doubts about that conclusion, once we accept that, the claim is effectively to a physiologically acceptable salt of tadalafil, and insufficiency then follows directly from the fact that it is not possible to make even one physiologically acceptable salt. This is the classic “how to make” variety of sufficiency. If you claim “Compound X” you have to tell a skilled person how to make Compound X, or the claim is invalid for insufficiency. The traditional view is that the purpose of the disclosure is to ensure that the public would have benefit of the invention after the term expired: see eg Minerals Separation [1947] ExCR 306, 316. If a skilled person cannot make the claimed compound with the guidance provided by the specification, the patentee could get the benefit of patent protection during the term, while keeping its monopoly through secrecy after the term expired. There is an extremely difficult question as to whether the invention has to be enabled across the full scope of the claim. But that doesn’t concern us here, as the specification did not provide sufficient instruction to allow a skilled person to make any physiologically acceptable salt.

A standard statement of the sufficiency requirement is that the specification must enable the skilled person to practice “the invention” [133]; citing s 27(3) and Teva 2012 SCC 60 [51]. But what is “the invention”? That term is notoriously ambiguous: “The word ‘invention’ has many meanings and nuances,” as Henderson pointed out in Patent Law of Canada (1994) 7–8. It can mean the inventive concept, which is to say the information disclosed in the patent which is the quid pro quo for the grant; it can means the invention as claimed, which is the set of all existing or future embodiments of the claimed invention; or it can mean a particular embodiment: see British United Shoe Machinery Co Ltd v A Fussell & Sons Ltd (1908) 25 RPC 631 (CA) 649–51. This led to a debate in this case in which Lilly argued that insufficiency was not available as an attack because the Defendants had not established the nature of the invention [139]. Lilly’s argument isn’t fleshed out in enough in St-Louis J’s decision for me to fully understand it, but I suspect the point is that the inventive concept was the discovery that tadalafil is an effective treatment for ED, and not the discovery of how to make a salt form of a compound that was already known to be effective. If that is indeed what Lilly was arguing, it is effectively another angle on the “or” argument, and one which, in my view, is better framed in terms of claim construction (as discussed in my last post) rather than sufficiency. So, given St-Louis J’s conclusion on the meaning of “or”, I would say she was right to reject Lilly’s argument on this point [143], to focus on whether the specification instructed how to make the salt [144]–[148]. And since the answer to that on the facts is “no,” I agree with her conclusion that the patent is invalid for insufficiency [149] (given her conclusion on the construction of “or”).

With all that said, the ambiguity as to the meaning of “the invention” made this part of the decision more convoluted that it needed to be. Given the ambiguity of the phrase “the invention, I suggest it might be desirable for the courts to simply stop using it altogether, in any context in which precision is necessary—which is to say, especially in defining validity doctrine. Instead, the law should specify “the invention as claimed” or “an embodiment of the invention,” or “the inventive concept,” as appropriate to the particular doctrine. That is a clarification that would probably have to be done by the FCA, since many authoritative statements of the law use the ambiguous term “invention.”

On that note, I would also point out that the law of sufficient disclosure has several threads that need to be disentangled, and the meaning of “the invention” isn’t necessarily the same for each aspect of the disclosure requirement. The SCC in Consolboard [1981] 1 SCR 504, 518, noted that the statutory provision, s 27(3) “gives the impression of a mélange of ideas gathered at random rather than an attempt to enunciate, clearly and concisely, a governing principle or principles.” While the Court in Consolboard at 518 suggested that the haphazard nature of the statutory provision might be the product of amendment over a period of many years, I think the truth is that the case law gives a similar impression of a mélange of ideas. This is illustrated by Thorson P’s well-known summary of the disclosure requirement established by the case law in Minerals Separation [1947] ExCR 306, 316–17. I won’t repeat it here, but it is plain on its face that it runs together several concepts that are sometimes only tangentially related.

Moving on, St-Louis J also held the asserted claims to be invalid for overbreadth:

[120] As I conclude that it is more probable than not that physiologically acceptable salts of tadalafil cannot be made I conclude, as the Defendants argue, that such a salt was not invented. The Asserted Claims therefore claim broader than what was invented and are thus invalid for overbreadth.

In my article Overbreadth in Canadian Patent Law: Part I (2020) 33 IPJ 21 and Part II (2021) 33 IPJ 147, I argued that a finding of invalidity for overbreath is almost always redundant with another established ground of invalidity. And so it is here. All the evidence St-Louis J reviewed in the context of overbreadth went to the question of whether went to whether a physiologically acceptable salt could be made [114]–[119]. Exactly the same facts that results in a finding of insufficiency—that the claim compound could not be made—was also the basis for the finding of overbreadth.

The problem with overbreadth is that it remains ill-defined. St-Louis J noted that “There are two (2) ways that a patent claim can fail for overbreadth (or overclaiming): it can be broader than the invention disclosed in the specification, or it can be broader than the invention made by the inventor” [109]. It seems that in this case she was relying on the second prong, as she noted that

Under the claims broader than invention made, it is a question of fact as to what the inventor actually invented [112].

But what does “actually invented” mean? As I argued in my Overbreadth article, if the patentee has sufficiency disclosed and claimed subject-matter that is new, useful and non-obvious, how could it be said that they had not “invented” the claimed subject-matter? Overbreadth has an air of being something distinct only because of the ambiguity in the phrase “the invention.” It sound very reasonable to say that the patentee cannot claim more than it invented, but if we try to define exactly what is meant by “invention,” it is difficult to give this proposition any content that is independent of the standard grounds of invalidity.

In any event, as noted, this is another case in which overbreadth is redundant as turning on the same analysis as another ground of invalidity, in this case insufficiency.

The third issue is as to utility. The utility argument turned entirely on the point that a physiologically acceptable salt could not be made: the Defendants argued that “the failure of the 784 Patent to indicate which of the many possible salts can be made as a physiologically acceptable salt of tadalafil” renders the asserted claims invalid for a lack of utility [154], while Lilly argued that “the Defendants have not met their burden to establish that a physiologically acceptable salt of tadalafil cannot be made” [159]. That is, the argument was that the invention lacked utility because a physiologically acceptable salt could not be made; it really just recapitulated the sufficiency argument. To my mind, this conflates utility and sufficiency. (This is not a criticism of St-Louis J, as this is the way the case was argued.) I have to admit, this conflation is very common. There was really no distinction between the two in early English practice, before the development of claims; if the specification describes a device that is not operable, there is no distinction to be made between a case where the patentee had devised a useful invention but failed to disclose it and a case where the specification disclosed the invention precisely, and the invention itself was useless, unless recourse is had to extrinsic evidence.

But with the advent of claims, we can distinguish between the two. The utility requirement asks whether the claimed invention works (or can be soundly predicted to work). Sufficiency asks whether the claimed invention can be made. These are different. Suppose, for example, that in the early days of genetic engineering, the patentee claims “Pure human insulin.” The claimed subject-matter, pure human insulin, is undoubtedly very useful. If the patentee cannot actually make it, the patent is invalid for insufficiency, but not for lack of utility. On the other hand, it may be easy to make something that lacks utility. If the patent claims “Oregano oil for the treatment of cancer,” the claim is sufficient, because oregano oil can be made and administered with the intent of treating cancer, but invalid for lack of utility because oregano oil does not in fact treat cancer. Applications for impossible inventions, like a perpetual motion machine, are traditionally rejected for both lack of utility and insufficiency; in my view, they should be rejected for insufficiency alone. After all, a device with greater power output than input would be extraordinarily useful—if it is could be built. With all that said, I acknowledge that there is a lot of confusion in the caselaw on this issue, stemming ultimately, in my view, from the fact that the distinction could not be drawn prior to the introduction of claims.

Ultimately, St-Louis J, wisely, in my view, declined to address the utility argument. The Defendants argued that”a claim must fail if, in addition to claiming something that is useful, it also claims something that is useless” [173]. In other words, the question is whether utility has to be established across the full scope of the claim. St-Louis J reviewed the caselaw and noted the uncertainty on the question of whether a claim is invalid if it claims a single inoperable species [175]–[178]. Given that she had already held the asserted claims invalid on two other grounds, she refrained from deciding this point of law, and so she declined to rule on the utility ground [178]. This is a difficult question, which is better left to a case in which it is the focus of the argument.

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