What Does “Or” Mean?

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

2,226,784 / tadalafil / CIALIS / NOC

This decision raises an important point as to the meaning of the word “or” in a claim, which I will address in this post. It also raises a variety of issues relating to validity, which I’ll address in my next post. For some reason, the decision is not available on the FC website, so I have linked to a version made available by Smart & Biggar.

The facts are quite 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, 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 any ionisable functional groups and consequently it is very difficult to make a salt form [103]. It may be possible to make some salts, but only under extreme conditions that would result in the degradation of 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]; I’ll discuss the invalidity holdings in my next post.

But what about the “or”? Even though tadalafil salts could not be made, there was no suggestion that tadalfil itself could not be made. If the patentee had eliminated the word “or” by doubling the number of claims, with one set directed to the salt forms, and separate parallel claims to tadalafil itself without the phrase “or a physiologically acceptable salt,” it seems clear that the claims to tadalafil would have been valid. In ordinary English, the word “or” is usually used to link alternatives, so one might think that drafting one claim with “or” should have the same effect as drafting two separate alternative claims.

It seems that Lilly did raise this argument, but too late [78]–[79]. St-Louis J nonetheless went on to briefly address the merits of the argument (citations omitted, original emphasis):

[80] In any event, even assuming that Lilly’s argument is properly before the Court, I find Lilly has not met its burden to demonstrate that the element is non-essential. Claim elements are presumed to be essential and a party alleging otherwise bears the onus of establishing non-essentiality. Also, and given my conclusion on [Lilly’s expert’s] credibility and reliability, the opinion he stated at paragraph 150 of his affidavit alone is insufficient to convince me that the formulation “or a physiologically acceptable salt” means such a salt could or could not be present, and that this element is non-essential. Conversely, [the Defendant’s expert] has found it to be necessary. Since Lilly has not met its burden to establish it is non-essential, I find the “physiologically acceptable salt” to be an essential element of the Asserted Claims.

This strikes me as a strange way of framing the issue. As I see it, the issue isn’t whether the phrase “physiologically acceptable salt” is essential, it is about the meaning of the word “or.” Lilly is not asking the court to read “physiologically acceptable salt” out of the claim, which is normally what happens with an non-essential element. It seems to me that what Lilly really wants is for the court to read “or” to mean “or.” Given that the issue was framed in terms of essentiality, I can't fault St-Louis J's analysis, but, in my view, this obscures the real issue. 

The other point that bothers me is St-Louis J’s reliance on expert evidence as to the meaning of the word “or”. The specification and claims must be construed as they would be understood by a skilled person, but at the same time, “claims construction is a matter of law for the judge”: see eg Whirlpool 2000 SCC 67 [61]. What this means is that expert witnesses must educate the judge as to the meaning of technical terms, but it is for the judge, armed with that knowledge, to decide on how the claim should be construed. The US Supreme Court put it this way in Teva v Sandoz 574 US 318 (2015) 332, quoting Markman  Markman 517 US 370 (1996) 388:

Where technical terms are used, or where the qualities of substances ... or any similar data necessary to the comprehension of the language of the patent are unknown to the judge, the testimony of witnesses may be received upon these subjects, and any other means of information be employed. But in the actual interpretation of the patent the court proceeds upon its own responsibility, as an arbiter of the law, giving to the patent its true and final character and force.

In this case, expert evidence was needed to educate the court as to what is meant by the technical term “physiologically acceptable salt,” but once the judge is armed with that knowledge, the interpretation of the interpretation of the ordinary English word “or” is a matter for the court, and expert evidence on this point is not necessary.

This claim drafting style is very common. If this result stands, it will have a major impact on drafting practice, as patent drafters will have to consider avoiding the word “or” in favour of separate claims, which will be problematic in light of the new excess claim fees. In the meantime, it will create uncertainty. In my view, it would have been much preferable if St-Louis J had rejected the argument on the basis that it had been raised too late, without going on to address it on the merits.