Monday, March 4, 2013

First Application of the Sildenafil Disclosure Requirement

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

Snider J’s Imatinib decision, at [336-387], is the first to apply the disclosure requirement since the SCC released Sildenafil 2012 SCC 60. Snider J has done an admirable job in applying a difficult doctrine, and she has clarified some important points. But the Imatinib decision also illustrates some difficulties that arise from unresolved ambiguities in Sildenafil itself.
Imatinib provides an interesting comparison with Sildenafil. In both cases the patent claimed a broad genus as well as specific compounds. In Sildenafil there were only two individually claimed compounds, and the patent did not disclose that only one of those two, sildenafil, had been tested in humans and shown to treat ED. In Imatinib there were six individually claimed compounds in the same group as imatinib, and test results suggesting that imatinib was potentially more effective than the other compounds as a treatment for chronic myeloid leukemia were not disclosed. Despite these similarities, the SCC held the patent to be invalid in Sildenafil, while Snider J held the ‘203 patent to be valid in Imatinib.

There were also important factual differences that mean that Imatinib is, in my view, consistent with Sildenafil despite the differing outcomes. In Sildenafil the SCC stated that the “key issue” was that “[a]s a matter of policy and sound statutory interpretation, patentees cannot be allowed to ‘game’ the system” by “obscuring the true invention” [80]. In Imatinib the evidence showed that the patentee was not trying to conceal the true invention. As of the filing date, the inventors themselves still did not know which compounds were best: “These researchers had found a number of effective inhibitors and had yet to perform further testing to determine which inhibitor would be most appropriate for drug development” [365; and see 363]. Of the six individually claimed compounds in so-called Group 2, which included imatinib, all had been subjected to similar testing, and all has shown sufficient activity to be considered promising candidates as of the filing date [360]. Indeed, as of the filing date, imatinib was not the highest priority compound [367]. The evidence led Snider J to conclude that “[i]n the case before me, I am satisfied that the patentee did not “game” the system” [387].

At the more technical level, Imatinib clarifies some aspects of the Sildenafil doctrine, and it also illustrates some of the tensions in the doctrine itself.

One important point emerging from Imatinib is that the Sildenafil doctrine does not require disclosure of data; it requires disclosure of the invention. Test results indicated differences between the compounds in various respects, and not all of that test data was disclosed. The plaintiffs argued that these test results should have been disclosed [370]. Snider J responded that (original emphasis):

[375] In my view. . .a lack of data cannot in and of itself result in a finding of insufficiency. Rather, one must ask whether the omission of the data from the patent prevents the person of ordinary skill in the art from using the invention as contemplated by the inventor.

This strikes me as entirely consistent with Sildenafil. In that case, the '446 patent disclosed that “patient studies conducted thus far have confirmed that one of the especially preferred compounds induces penile erection in impotent males,” but it did not disclosure the data from the test, or that the compound was sildenafil. It appears from the SCC decision that the real shortcoming was the failure to disclose that the compound was sildenafil [73]. Had the disclosure referred to “sildenafil” rather than “one of the especially preferred compounds,” it seems that the patent would have been upheld, even if the specific test data had not been presented. There is certainly no suggestion in Sildenafil that the test data itself has to be disclosed. As Snider J indicates, this is not to say that the Sildenafil doctrine can never imply an obligation to disclose test data, but it does imply that disclosure of data is not an element of the doctrine.

Secondly, the Sildenafil doctrine is not a “best mode” requirement. Snider J noted that in arguing that the data in question should have been disclosed, “the Plaintiffs are really raising a ‘best mode’ argument. In other words, the Plaintiffs are asserting that the '203 Patent should have disclosed that [imatinib] was the best of the six compounds. In the face of the evidence that all six compounds were effective inhibitors, this argument cannot be sustained. . . .There is no requirement in s. 27(3) that ‘best mode’ must be disclosed in inventions that are not machines” [376]. Again, I believe this is consistent withSildenafil, but here some line drawing issues arise. The best mode issue was argued in Sildenafil in the FCA, and rejected on the same basis that it does not apply to machines: 2010 FCA 242 [72]. It was not mentioned at the SCC level, so formally, the disclosure requirement in Sildenafil is not a best mode requirement. However, the Sildenafil doctrine is akin to a best mode requirement, in that on the facts the SCC required disclosure of information that differentiated the usefulness of the claimed compounds.

The question is how to draw the line between information that must be disclosed and that which need not be. In Sildenafil the SCC focused on the question “What is the invention in Patent ‘446?” [53]. So, as recognized by Snider J in Imatinib [344], Sildenafil holds that what must be disclosed is not the best mode, but “What is your invention?” In principle, this is preferable to a best mode requirement, because it is nominally an objective inquiry. The best mode requirement depends on the inventor’s subjective state of mind. This results in uncertainty as to what should be disclosed, and may result in disclosure of material of marginal value, where the embodiment thought to be best at the time of filing turns out not to be best in fact. This latter problem is illustrated on the facts in Imatinib, in which it appears that imatinib was not considered the most promising compound as of the filing date [367].

A “what is your invention” inquiry should avoid these problems, if the invention can be defined objectively. However, even though the Sildenafil decision turns on disclosure of “the invention,” it did not provide a clear framework, either conceptually or on the facts, for answering the central question, “what is your invention?” In Sildenafil the SCC shifted between saying that the invention was the use of compounds that are effective in treating ED [68], and the use of sildenafil in treating ED [72]. This was a crucial question, given that the courts below had upheld that patent on the basis that “the invention” is defined on a claim-by-claim basis, and the SCC reversed on this point [54-55]. In Imatinib, Snider J defined the invention as being either the invention of a class compounds that selectively inhibit kinases [351], or, alternatively, as being two inventions, one for each of two groups of compounds that were distinguished functionally and in the disclosure itself as inhibiting different classes of kinase [355]. The SCC in Sildenafil did acknowledge the possibility that there might be more than one invention in a single patent [64], but, as Imatinib illustrates, it is difficult to know when there is really only one invention, and when there is more than one. Even Snider J’s alternative definition of “the invention” largely ignores the use claims, which were directed not simply to kinase inhibition, but to treatment of certain conditions. It is very difficult to see how “the invention” related to these claims is mere inhibition of kinases, as opposed to some kind of in vivo activity, and indeed this is how Snider J construed these claims [268]. Suppose that on the facts the claimed compounds were known, and were known to be kinase inhibitors, so that the compound claims were invalid as being anticipated, but that recognizing that these kinase inhibitors were useful in treating cancer was inventive, so that the use claims were valid. In that hypothetical I think we would have to say that the use claims embodied a separate invention, namely the use of known compounds to treat cancer. Does this mean that the answer to “what is your invention?” turns on facts not known to the inventor? This consistent with, and is arguably a reflection of the rule that claims stand and fall independently. But this is problematic if the disclosure requirement, which must be satisfied by the applicant at the time of filing, turns on the answer to this question. This problem did not feature in the Imatinib case, but this may be because Snider J’s analysis the specific points which the plaintiffs argued constituted insufficient disclosure is only loosely tied to her prior discussion of “what is the invention?”

None of this is to criticize Snider J’s analysis; my view is that the difficulty stems from the SCC Sildenafil decision itself, which does not provide a clear framework, either conceptually or on the facts, for defining “the invention.” In Sildenafil the SCC was able to skirt this issue, as it seems intuitively evident that the real invention was the discovery that sildenafil in particular could treat ED. The facts of imatinib are very different. While it did turn out that one of the claimed compounds was an important commercial success, this was not at all clear at the time, so the discovery really was that of the class of compounds. But the use claims and the disclosure of functionally different groups of compounds, within the broad envelope of kinase inhibition, illustrate that it is difficult to view each claim as disclosing the same invention. Ultimately, I think that the facts of Imatinib illustrate that the FC and FCA in Sildenafil were right to consider that each claim, at least potentially, defines a separate “invention.”

This is not to say that the SCC Sildenafil decision was wrong, but only that it was wrongly framed. I would suggest that the Sildenafil doctrine is best understood as a good faith disclosure requirement, though it does not go as far as amounting to a best mode requirement. I rather hope that I am wrong in this, because a good faith requirement is inherently uncertain. A good faith requirement cannot mean that the patentee must disclose everything of possible relevance, including every dead end or inconclusive experiment. But if complete disclosure of everything is not the rule, there must be some judgment by the court as to whether the important information has been disclosed. If it is possible, I would prefer to see a more objective inquiry, and perhaps the cases to come will develop the kind of clear definition of “the invention” that was not provided in Sildenafil. But my feeling is that the focus on “the invention” in Sildenafil was a way of giving the appearance of objectivity to a case in which the real objection was that the patentee had withheld important information. If we focus on defining "the invention," the uncertainty will simply emerge in that context. It is better to acknowledge openly that it is a good faith requirement that consequently requires the exercise of sound judgment by the court in determining what is important information that should have been disclosed.

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