Wednesday, February 13, 2013

Cryptic Obvious to Try Analysis

Pfizer Canada Inc v Pharmascience Inc / pregabalin (NOC) 2013 FC 120 Hughes J
            2,255,652 – LYRICA

The ‘652 patent claims the use of pregabalin for the treatment of pain. As discussed in a previous post, Hughes J found it to be invalid for lack of utility / overbreadth. However, he also held it was not obvious.

While the discussion of obviousness was brief, it appears the attack was based on an obvious-to-try argument, as Hughes J began his analysis at [186] by quoting the relevant passages from Sanofi 2008 SCC 61 and Pfizer / sildenafil (NOC) 2009 FCA 8. Pregabalin was a compound known to be useful as an anticonvulsant, and the evidence indicated that at the relevant time “physicians would try or expect that anticonvulsants would be useful in treating some forms of pain,” [193], though at the same time a skilled person “would not have an expectation that pregabalin would be useful to treat pain without making and testing it” [194].

After his review of evidence, Hughes J’s reasoning on obviousness is contained entirely in the following passage:

[202] . . .I accept that, looking at all the evidence of all the experts, that while anticonvulsants were looked at - at least by some researchers - as a fruitful field to try and see if any of them worked with respect to pain, one would not know, until it was tested, whether it worked in fact, and without any harmful effects. The statements of Lord Justice Kitchin at paragraph 90 of his Reasons in MedImmune, [[2012] EWCA Civ 1234], are appropriate:
…there are areas of technology such as pharmaceuticals and biotechnology which are heavily dependant on research, where workers are faced with many possible answers to explore but have little idea if any one of them will prove fruitful. Nevertheless they do pursue them in the hope that they will find new and useful products. They plainly would not carry out this work if the prospects of success were so low as not to make them worthwhile. But denial of patent protection in all such cases would act as a significant deterrent to research.
[203] Therefore, I find that Pharmascience’s allegation as to obviousness is not justified.

This reasoning is cryptic. It might be taken as saying that because one would not know whether the particular compound would work until it was tested, therefore it was not obvious, particularly in light of the need to provide an incentive for such experimental research. But it is exactly when success can be predicted, but the exact form of the success cannot, that the obvious to try analysis applies. As the EWCA said in the next paragraph of the MedImmune decision:

For these reasons, the judgments of the courts in England and Wales and of the Boards of Appeal of the EPO often reveal an enquiry by the tribunal into whether it was obvious to pursue a particular approach with a reasonable or fair expectation of success as opposed to a hope to succeed.

A good example is provided by Hughes J’s decision in Ratiopharm v Pfizer / amlodipine besylate 2009 FC 711 aff’d 2010 FCA 204, in which the maleate salt of amlodipine was the preferred embodiment in the prior art. The maleate salt had certain production problems, such as stickiness. The patentee conducted a routine salt screen, which is to say it prepared a variety of pharmaceutically acceptable salts of amlodipine, and determined that the besylate salt had the best set of manufacturing properties of those salts tested. It could not be predicted in advance that the besylate in particular would be the best salt (or it would not have been necessary to carry out the screen) but it was obvious to try a salt screen, and it was obvious that one of the salts tested would succeed, at least in the sense of being better than the others. Therefore the invention was obvious.

As noted, Hughes J’s obviousness reasoning in this case was very brief, no doubt because the conclusion on utility / ovrebreadth was dispositive, and it would be wrong to read too much into it. I suggest that his decision in the amlodipine besylate case is a better guide to the obvious to try test than is his reasoning in this case.

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