Friday, March 1, 2013

Miscellaneous Issues in Imatinib

Teva Canada Ltd v Novartis AG / imatinib 2013 FC 141, Snider J
            GLEEVEC / imatinib mesylate / 2,093,203

As well as the promise of the patent, discussed yesterday, Snider J’s imatinib decision is the first application of the SCC  Sildenafil disclosure requirement, and it also raises interesting issues related to sound prediction. I am still working on posts on those topics. In the meantime, this post discusses some miscellaneous emerging from the decision.

  • Differentiated promise of utility
  • What is a scintilla?
  • Burden of proof
  • POSITA may be an expert
Differentiated promise of utility
The plaintiffs submitted that every claim must have the same utility [174]. The issue arose in a somewhat convoluted fashion. As discussed in yesterday’s post, the plaintiffs argued that the patent promised in vivotherapeutical effect. [170]. This argument was based primarily on the use claims, such as Claim 46, which claimed “use in the chemotherapy of tumours.” Snider J had no difficulty holding that this would incorporate some notion of in vivo efficacy [180.2], in particular the potential for in vivo treatment [183]. In order to leverage this holding with respect to the use claims into a similarly elevated utility requirement for the compound claims, the plaintiffs argued that all the claims in the patent must have the same utility.

Snider J rejected this argument on the basis that “this just does not accord with the reality of the '203 Patent. From the first paragraph in the '203 Patent, the skilled reader is informed that there are four aspects to the patent and four groups of claims that match those aspects” [174]. It may be that in some patents every claim has the same utility, but this is not a requirement as a matter of law [179]. It seems to me that this must be right. The plaintiffs’ argument would effectively read a use requirement from a use claim into a compound claim, which has no such limitation. The basis of the plaintiffs’ argument that every claim must have the same utility is not clear to me from Snider J’s decision. In particular, I can’t tell whether the argument was that as a matter of law, all claims must have the same utility – a kind of “unity of utility” requirement – or if it was simply that on the facts, on the claims in this patent had the same utility. In any event, Snider J’s decision clearly holds that every claim need not have the same utility.

What is a scintilla?
In principle, a mere “scintilla” of utility is enough to support a patent; but how much is a “scintilla”? There is very little case law on point, since utility is almost always assessed on the basis of the promise of the patent. In this case, the point arose because Snider J accepted Novartis’ position that the patent promises only selective inhibition of certain kinases [205]. The question then arises, is this enough utility to support a patent? The scintilla must set a minimum standard; a patentee cannot get a patent for an invention that does not have even a scintilla of utility by promising even less. Snider J had not the slightest hesitation in holding that selective kinase inhibition met the scintilla standard. This is consistent with other Canadian cases which generally find that potential to treat a disease is sufficient utility, and it is probable that this is well above the absolute minimum: see eg HGS v Eli Lilly [2011] UKSC 51 (blogged here) finding a much more speculative use for a compound was sufficient to satisfy the minimum utility requirement. What is interesting is that Snider J seemed to approach this question as one of fact, saying “The experts. . . agreed that selective kinase inhibition is a ‘valuable pharmacological property’. That was a known fact as of April 1, 1993" [206]. But arguably this should be a question of law, or mixed fact and law, as the fact that a compound has a commercial market is not in itself sufficient to establish patentable utility: see eg In re Fisher 421 F3d 1365 (Fed Cir 2005). Not too much should be read into this, as the utility of selective kinase inhibition was not contested.

Burden of Proof
In Wellcome / AZT 2002 SCC 77 the SCC held that in a validity challenge to a granted patent the decision of the Commissioner of Patents to grant the patent is “entitled to limited deference,” [41] and the appropriate “standard of review” is “reasonableness simpliciter” [44]. This confused administrative law principles with what is in fact a question of the interpretation of the statutory presumption of validity set out in s 43(2). In a strongly reasoned passage in Eli Lilly / cefaclor 2009 FC 991 [347ff], Gauthier J refused to follow the SCC on this point, and, as discussed here, the Federal Courts have since generally ignored the SCC’s Wellcome / AZT decision on this point. Snider J’s imatinib decision follows this trend, as she cites Gauthier J’s cefaclor decision regarding the presumption of validity, without any mention at all of SCC’s Wellcome / AZT.

POSITA may be an expert
One of Novartis’ experts got tripped up in explaining his understanding of the question he was to address, and stated that “It's really about whether an expert in cancer biology at the time” would have been able to reasonably infer certain conclusions. The plaintiffs took exception to this. Snider J was ultimately satisfied that the expert in question understood his task. She also remarked that “the notional skilled person, in this case and as discussed below, will have considerable expertise in medicinal chemistry. A person with such expertise may well be referred to as an ‘expert’” [35]. In other words, in a sufficiently technical field, even a person of ordinary skill may be what would colloquially be called an “expert”.

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