Recently, the Federal Court of Appeal released its decision in Pharmascience Inc. v. Bristol-Myers Squibb Canada Co., 2022 2022 FCA 142 142 (the "Decision"). The Decision touches on various issues, but I want to focus on one: the relevant date for assessing disclosure sufficiency.
The Decision results from consolidated appeals of Zinn J.'s decision in Bristol-Myers Squibb v. Pharmascience and Sandoz, 2021 2021 FC 1 1, which found Canadian Patent nos. 2,461,202 ("the '202 patent") and 2,791,171 ("the '171 patent"), Bristol-Myers Squibb's patents for apixaban, to be valid. The '202 patent claims the compound apixaban and its use in treating thromboembolic disorders (e.g., stroke), and the '171 patent claims formulations of apixaban. Below, I discuss the disclosure sufficiency attack on the '202 patent.
Previously, the Federal Court of Appeal, in Idenix Pharmaceuticals, Inc. v. Gilead Pharmasset LLC., 20172017 FCA 161 FCA 161 ("Idenix"), held that the filing date is the relevant date for assessing disclosure sufficiency:
Since the filing date, all three synthesis pathways... have been proven to work.... According to Idenix, this fact supports the sufficiency of its disclosure because no matter which pathway the skilled person chose, they would arrive at the Claimed Compound [a compound claimed in the issued patent]. Though reversed on other points, this Court held in Novopharm Limited v. Pfizer Canada Inc., 2010 FCA 242 at paragraph 79,  2 F.C.R. 69, that courts must "determine whether the disclosure was sufficient as of the date of filing. As a result, anything which occurred subsequent thereto is of no relevance." In my view, Idenix's argument reflects the benefit of hindsight rather than the knowledge of the skilled person at the relevant date. (Idenix, ; commentary in square brackets, emphasis added)
Generally, when we assess the validity of a patent, we of course are considering the patent's specification as issued; not as filed, nor as published. After all, we can only invalidate a patent, and not a pending application for one. So then, what exactly do we mean when we say that a disclosure's sufficiency is assessed as of the filing date? There are other factors, outside of the scope of the issued specification, that come into play in assessing disclosure sufficiency; the assessment is made from the perspective of the person of skill in the relevant art, in view of the common general knowledge in the art as of the relevant date. What was commonly known in the art at the filing date may be very different from what was known at other key dates, such as the date of publication or the issue date, and so despite that we are assessing the specification as issued, we are doing so in view of the state of the art as of the filing date. This is no different than other bases for assessing patent validity, such as novelty and obviousness (where the claims as issued are assessed in view of the state of the art as of the relevant claim's "claim date" (i.e., the filing date or, if applicable, the earlier priority date for the claimed subject-matter), or utility (where the utility of the claims as issued is assessed as of the filing date). Locke J.A. acknowledges this in the Decision (para. ), and then states the following:
Even in Teva Canada Ltd. v. Pfizer Canada Inc., 2012 SCC 60,  3 S.C.R. 625 (Sildenafil), which found the patent in issue invalid for insufficiency, it was the specification as issued that was considered, not the specification as it appeared at some prior date.
This approach is consistent with the text of subsection 27(3) of the Patent Act. PMS notes that subsection 27(3) identifies the requirements of the "specification", and argues that subsection 27(2) indicates that it is the specification as filed that must meet those requirements. However, such an argument does not withstand scrutiny. Firstly, it would effectively read out subsection 27(6), which contemplates amendments to bring the application into compliance with the sufficiency requirements. Secondly, a similar argument would seem to apply to the requirements for novelty (the opposite of anticipation) and inventiveness (the opposite of obviousness). Sections 28.2 and 28.3, which address these issues, both refer to requirements for "[t]he subject-matter defined by a claim in an application for a patent." PMS's focus on the specification as filed for determining sufficiency would also imply a focus on the claims as filed for anticipation and obviousness, since the relevant provisions mention "a claim in an application". I can see no reason that the approach that PMS urges for sufficiency would not apply similarly to anticipation and obviousness. However, as indicated above, there is no doubt that anticipation and obviousness are assessed based on the issued claims, not those pending prior to issuance. (Decision, paras.  and , emphasis in original)
I decided to write about this aspect of the Decision because the public commentary reveals some confusion as to whether Locke J.A. is arguing that the filing date is not the relevant date for assessing sufficiency, or if he is simply stating that the specification as issued is what is relevant. Of course, the two are not mutually exclusive; indeed, as discussed above, I believe that the jurisprudence has established that it is the specification as issued that is assessed for sufficiency, in view of the state of the art as of the filing date. Generally, we are asking if the skilled person could put the invention claimed in the issued patent into practice using only the contents of the patent specification, as supplemented by the common general knowledge (such as the tools and techniques) that existed at the filing date.
Of course, there is the practical question of whether the specification as issued can differ appreciably from the specification as filed, given that section 38.2 of the Patent Act does not allow amendments that cannot be reasonably inferred from the specification and drawings contained in the application on its filing date. Locke J.A. does state that section 38.2 of the Patent Act is "without restriction as to whether such amendments might buttress the sufficiency of the specification." (Decision, para. ) For example, in this case, the claims of the as-filed and as-published specification did not focus on apixaban; it was not until shortly before the '202 patent was issued that the claims were amended to focus on apixaban. Despite that the issue was not raised at trial, Locke J.A. did state that he would not consider those amendments not to be reasonably inferable, in view of an example that was included in the originally filed specification of the '202 patent.If we view the Decision as establishing the issue date as the relevant date for assessing sufficiency, including with respect to determining the state of the art, then we can consider this issue unsettled, and perhaps this is where the confusion has arisen for some. However, Locke J.A.'s comments focus on the state of the specification at the issue date, and so if the Decision merely affirms that it is the specification as issued that is assessed for sufficiency, then perhaps the issue of the relevant date for assessing the state of the art is left undisturbed, and the Decision accords with earlier jurisprudence. Locke J.A. does state that "[i]t is important to draw a distinction between the date for determining sufficiency and the claims to be considered in that determination." (Decision, para. ) I am inclined to think that the law remains undisturbed.
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