2,307,632 / gatifloxacin ophthalmic
Yesterday morning I posted on Shire v Apotex 2016 FC 382, in which Locke J gave little weight to the practice of “blinding” the expert witness; then in the afternoon the FC released Allergan v Apotex, in which Zinn J has taken almost the opposite approach to the same issue. Apotex prevailed on the issue of obviousness primarily because Zinn J preferred the evidence of one of Apotex’s witnesses , and he preferred the evidence of that witness primarily because she was blinded (though also in part because her expertise was more directly relevant to the issue at hand) (my emphasis):
 While I am not convinced that all of these alleged flaws are made out, I am satisfied, for the following reasons, that the evidence of Dr. Sheardown [Apotex’s expert] is to be preferred and given more weight than that of Dr. Fix [Allergan’s expert] and Dr. Myrdal [Apotex’s expert].
 As noted by Apotex, Dr. Fix was not blinded; he offered his opinion after having read the 632 Patent and Apotex’s NOA and after having discussed both with Allergan. The Supreme Court of Canada in Apotex Inc v Sanofi-Synthelabo Canada Inc, 2008 SCC 61, 3 SCR 265 [Plavix SCC] at para 67, directs that an obviousness assessment is to be made “without any knowledge of the alleged invention as claimed.” Relying on this observation, this Court has recognized that evidence from experts who have not seen the patent nor been apprised of the positions of the litigants is to be given greater weight on issues going to obviousness and patent construction than the evidence of an expert with full knowledge of the patent’s disclosure and the positions of the parties: [citations omitted]
 Like Dr. Fix, Dr. Myrdal had prior knowledge of the 632 Patent (or the U.S. equivalent) and the positions of the parties. As acknowledged by Apotex, “[Dr. Myrdal] testified in a United States case on the corresponding patent and his evidence … in the present proceeding was consistent with his U.S. evidence.”
 Unlike the other experts in pharmaceutical formulation, Dr. Sheardown expressed her opinion on the common general knowledge and the prior art with no knowledge of the patent at issue or the positions of the parties. As such, her responses to the questions asked of her came without any influence, conscious or unconscious. Moreover, of the three, only Dr. Sheardown’s expertise focused on “studying and developing delivery formulations for ophthalmic applications.” Dr. Fix and Dr. Myrdal are expert formulators. However, given that the alleged invention in the claims at issue is specifically directed to an ophthalmic medication in the form of an eye drop, I am of the view that the evidence of the one expert specializing in that area, whose opinion is offered with no possible influence, is to be preferred.
As discussed here, the FCA in Mishan v Supertek 2015 FCA 163 recognized an inherent tension in the SCC’s approach to obviousness. On the one hand, Sanofi  says that the differences between the state of the art and the inventive concept must be “[v]iewed without any knowledge of the alleged invention as claimed.” But that is impossible: “The differences are based on the inventive concept of the claims in issue and the relevant prior art and, therefore, are determined based on some knowledge of what is claimed in the patent in issue. Therefore, some knowledge of the alleged invention will be reflected in the differences that are analyzed in applying step 4 of the Sanofi test” [Mishan v Supertek ].
So far as I can tell, in this case that tension was resolved by having Dr Sheardown express her opinion “on the common general knowledge and the prior art”  without knowledge of the patent or the position of the parties, but she must have then been provided with the patent before opining that “There is no practical difference between the inventive concept of the claims of the 632 Patent and the common general knowledge. Any differences between the inventive concept and the claims of the 632 Patent and what was known to the skilled person as of August 1998 constituted steps that would have been obvious to the skilled person” .
There are also two sides to this debate as a matter of policy. While blinding an expert may help avoid hindsight bias, unless the expert is asked to focus on “where the shoe pinches” it might be difficult to elicit relevant evidence. Also, as noted in yesterday’s post, the issue has arisen in the context of claim construction as well as obviousness. Is there a principled difference between the two contexts which would rationalize the divergent case law? In any event, the law on this point continues to develop, but until some consensus is reached it will be difficult to know how to instruct an expert.