Saturday, March 2, 2013

Must the Line of Reasoning be Disclosed in the Patent?

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

In its Latanoprost decision, 2011 FCA 236, the FCA remarked on the disclosure requirement related to the “line of reasoning” branch of the sound prediction doctrine, suggesting that the line of reasoning must be disclosed in the patent itself, and even that the line of reasoning must be found entirely in the patent [original emphasis]:

[42] The inventor's line of reasoning is nowhere to be found in the disclosure of the '132 patent. When asked where, in the patent, was disclosed the line of reasoning, Dr. Wolff could not point to any excerpt. Dr. Fechtner’s was led to the same conclusion:

Q. Yes. So can you point me in the patent where the inventor say here’s the rational from Point A, one time single use, the tables, to Point B, lifelong chronic use, the claims? Where’s the description of that rational in the patent?
A. I don’t find explicitly what you’re describing.

[43] At the hearing, counsel for Pfizer argued that the line of reasoning was to be found in the studies listed in the "References" section of the patent (Patent '132, at pages 30 and 31). Pfizer also took the position that a POSITA, taking the prior art as a whole, would be able to infer that multiple doses of latanoprost would give the same results as the single dose studies.

[44] This position seems at odds with the concept of disclosure in patent law. In Wellcome AZT, Justice Binnie stated that if utility is not demonstrated at the time of filing, the quid pro quo the applicant offers in exchange for the patent monopoly is a sound prediction of utility (Welcome AZT, at paragraph 70). As the applicant is the one who will benefit from the monopoly, I am of the view that only he, and not the authors or inventors of the prior art, can discharge himself of the obligation of disclosure. Besides, our Court found in Eli Lilly Canada Inc. v. Apotex Inc., 2009 FCA 97, at paragraph 17 that a patent that provides no more disclosure than is available in the prior art does not provide a sound basis for the prediction.

In her imatinib decision, Snider J interpreted this passage as modestly as possible. The FCA went on to say that “Moreover, Pfizer pointed to no evidence on the record supporting its position. None of Pfizer's experts bridged the gap between the single doses studies and the claimed chronic use” [45]. Snider J seized on this, remarking that “In Latanoprost, the Court of Appeal acknowledged that expert evidence relating to the knowledge of the skilled person might bridge the gap between the factual basis disclosed in the patent and the prediction of the inventor” [292]. This is a reasonable alternative reading of Latanoprost; while the FCA, in the paragraphs quoted above, suggested that the line of reasoning had to be found in the patent, it also held that even if it were possible to bring the gap with evidence not in the patent, the patentee in this case had not done so. 

In my view, when faced with these alternatives, Snider J was entirely right to emphasize the potential for gap bridging. The notion that the line of reasoning must be entirely disclosed in the patent itself is absurd, as the facts in imatinib illustrate. It was well known that chronic myeloid leukemia was caused by BCR-ABL kinase, and it was well known that a kinase inhibitor that was selective for BCR-ABL would potentially treat that disease. The breakthrough was in finding a compound that acted as a selective BCR-ABL kinase inhibitor, not in drawing any of the links in the chain of reasoning. The only element of the line of reasoning that had been disclosed was the fact that the tested compounds selectively inhibit ABL kinase, and this is arguably part of the factual basis rather than the line of reasoning [313]. The gap to be bridged amounted to almost the entire line of reasoning. But there is nothing wrong with that. There is no good reason why the disclosure should include a discussion of what was already well-known in the art. It is precisely to avoid the need for such lengthy and redundant disclosure that the law takes the reader of the patent to be a person skilled in the art. It is true that Wellcome / AZT 2002 SCC 77 [70] suggests that there might be a need to disclose the line of reasoning in the patent, but it was no more than a hint, and it was expressly obiter. The common law method of reasoning is to test the principles according to the facts, and because the lower courts see far more patent cases than the SCC, they are in a good position to see when a hint dropped by the SCC makes sense, and when it does not. Similarly, inappropriate hints dropped by the FCA should also be modestly interpreted, as Snider J has done in this case.

(Note that I have previously criticized the FCA Latanoprost decision on the separate point that it construed the promise of the patent without reference to the text of the patent itself.)

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