Sunday, March 3, 2013

Utility of Genus Claims Turns on the Expert Evidence

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

Previous posts have discussed the key compound claims and use claims in the ‘203 patent. This post turns to the genus claims. Because not all of the compounds in the genus claims had been tested, their validity turned on the doctrine of sound prediction [248]. Snider J had concluded that all of the tested compounds had utility as kinase inhibitors, and the key question in respect of the genus claims was “whether it is reasonable to predict, on the basis of a few examples, that all of the compounds of the general claim will operate in a similar fashion” [250]. This is fundamentally a question of fact which Snider J answered on the basis of the testimony of the expert witnesses.

Interestingly, Snider J did not explicitly apply the three part test for sound prediction. Presumably the factual basis is the individual compounds which were shown to have utility, and this was disclosed in the patent. I noted in my last post that the line of reasoning relating to the utility of the use claims was almost entirely provided by expert evidence. This is even more true in respect of the genus claims. The line of reasoning concerned the degree to which the substituents permitted by the claim would change the shape of the compounds. This was introduced entirely through the evidence of expert witnesses [253-62], and was not discussed at all in the patent. I view this as completely unobjectionable, for reasons discussed in my last post. Whether the FCA will see things the same way remains to be seen.

In the result, the broadest claims were held invalid, on the basis that “we cannot extrapolate from the efficacy of the tested compounds to conclude that all of the compounds of Claims 1, 2, 3 and 4 have the utility promised by the '203 Patent” [256]. However, two important genus claims, Claims 5 and 7, which include imatinib, where held to have utility, on the basis that “that it is a reasonable inference that any compound of Claims 5 or 7 would be likely to exhibit the same inhibitory characteristics as the tested compounds” [263]. Claim 5 was narrower than Claim 4 [257], but there was no sharp distinction to be drawn between Claims 4 and 5; it was simply a matter of the "comfort zone" of predictability [260]. Claim 7 was slightly more restrictive than Claim 5, and so utility could also be predicted [261]. (Claims 6 and 8 are genus claims that do not include imatinib, and they were not addressed by the parties [249].)

It is significant that a modest construction of the promise of the patent was important to the conclusion that Claims 5 and 7 were valid. There was some evidence that some of the compounds in these claims could not be predicted to have in vivo utility, but this was irrelevant because Snider J had held that only in vitro utility was promised [257-58].

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