Case Comment

Apotex Inc. v.
Pfizer Canada Inc. (et al)

citation(s): 2009 FCA 8 (F.C.A. per Noel J.A., Letourneau and Blais JJ.A. concurring) online

copyright 2010 Donald M. Cameron, Cameron MacKendrick LLP



This is the first application of the obviousness test from Apotex Inc. v. Sanofi-Synthelabo Canada Inc., 2008 SCC 61 ("Sanofi-Synthelabo")

[2] In the Memorandum filed in support of its appeal, the appellant pursued the issues of faulty disclaimer, claims broader than the invention made and disclosed, patent ineligibility, obviousness and anticipation. Two days prior to the scheduled hearing, the appellant wrote to advise that it would only pursue the appeal in respect of the issue of obviousness, intending to rely upon the decision of the Supreme Court of Canada in Apotex Inc. v. Sanofi-Synthelabo Canada Inc., 2008 SCC 61 (Sanofi-Synthelabo) released November 6, 2008.

[11] More specifically, with respect to the issue of obviousness, which is the only one left to be considered in the present appeal, the Federal Court Judge held that the core question in the case was whether the person of ordinary skill in the art, in the light of the state of the art and of common general knowledge as at the claimed date of invention, would have found the solution taught by the patent. The “solution taught by the patent” that he used for this inquiry was consistent with his claim construction, namely “the appreciation that the oral administration of sildenafil, as a potent PDE5 inhibitor, would be useful in the treatment of [ED] in men” (Reasons, para. 57).


[3] The respondents market a drug for the treatment of Erectile Dysfunction (ED), under the brand name VIAGRA.

[4] The respondents obtained patent protection for the use of the compound sildenafil for this purpose. They obtained the ‘446 patent on July 7,1998 from an application filed in Canada on May 13, 1994 ...

[10] The Federal Court Judge concluded that, based on the evidence, the respondents’ discovery was truly inventive and that none of the appellant’s attacks on the patent should succeed. He held that the respondents met their legal burden to establish the validity of the ‘446 patent on a balance of probabilities and that the application to prohibit the Minister from issuing an NOC to the appellant until after the expiry of the ‘446 patent should be granted.

The Decision

[15] In concluding his obviousness analysis, the Federal Court Judge held that what emerged from the prior art was a picture of a field of rapidly advancing science which led to the discovery, but which did not point directly to it. He specifically noted that, in 1993, none of the scientists who had speculated that PDE inhibition might be a factor in erectile tissue physiology, arrived at the solution of using oral administration of sildenafil as a PDE5 inhibitor in the treatment of ED. He therefore concluded that the evidence did not establish that the solution taught by the patent was obvious at the time. At best, the Federal Court Judge noted that there was speculation, which in hindsight proved to be correct, that PDE5 inhibitors might treat impotence.

[16] In addition to his findings on the state of the art, the Federal Court Judge also considered the other factors for analyzing obviousness as set out in Novopharm Ltd. v. Janssen-Ortho Inc. 2007 FCA 217, aff’g 2006 FC 1234 (Novopharm). He found that there was a strong motivation to come up with a convenient drug treatment for ED, and genuine surprise when the respondents did so. He also noted the cumulative effect of the secondary indicia such as the commercial success of VIAGRA®, its wide use, and the surprise that accompanied its first publication, all of which he found to further support his conclusion that the use of sildenafil to treat ED was not obvious.

[28] I take it from this that the test adopted by the Supreme Court is a precise application of the test loosely referred to as “worth a try”. After having noted Apotex’ argument that the “worth a try” test should be accepted (para. 55), Rothstein J. never again uses the expression “worth a try” and the error which he identifies in the matter before him is the failure to apply the “obvious to try” test (para. 82).

[29] The test recognized is “obvious to try” where the word “obvious” means “very plain”. According to this test, an invention is not made obvious because the prior art would have alerted the person skilled in the art to the possibility that something might be worth trying. The invention must be more or less self-evident. The issue which must be decided in this appeal is whether the Federal Court Judge failed to apply this test. [30] In my respectful view, he did not. While the Federal Court Judge does not use the phrase “obvious to try”, his reasons show that he conducted his analysis along the dividing line drawn in Sanofi-Synthelabo. Specifically, he rejected the contention that the invention was obvious based on mere possibilities or speculation and looked for evidence that the invention was more or less self-evident.

[31] A review of the Federal Court Judge’s assessment of the experts’ opinions and the literature references tendered in evidence supports this conclusion. More specifically, it is apparent that he turned his mind to the question of whether the patented invention was more or less self-evident in examining this evidence. Indeed, the following excerpts show that he found, based on the expert evidence, that the invention was not self-evident: ...

[32] In the same vein, it is also apparent that the Federal Court Judge was looking for more than mere possibilities in examining the primary literature references relied upon by the appellant. With respect to the Rajfer and Trigo-Rocha papers, he found that they did not disclose, or even suggest, that a cGMP PDE5 inhibitor, like sildenafil, would treat ED: ...

[33] With respect to the Murray paper, while it identified some cGMP PDE5 inhibitors, their relationship to smooth muscle relaxation and their potential uses as a drug therapy, the Federal Court Judge found that (Reasons, para. 105) “… at best, [the paper could] be taken to suggest that there [was] a possibility that cGMP PDE5 inhibitors could be developed for ED, subject to human testing, but that, in any event, [it] point[ed] to the potential utility of zaprinast, not sildenafil.”

[34] Similarly, the Federal Court Judge noted that a similar conclusion could be drawn from the Bush paper, namely that it was not a given that a specific cGMP PDE inhibitor would be clinically effective in treating ED and that it was a possibility to be considered and further researched: ...

[35] The Federal Court Judge goes on to confirm that the most that he could gather from the prior art at the priority date was that using orally administered sildenafil to treat ED was “worth a try”: ...

In so saying, the Federal Court Judge equates the expression “worth a try” with “a possibility worth exploring” as Dr. Ringrose had characterized the matter when he suggested that sildenafil be tried as a treatment for impotence (Reasons, para. 61).

[36] It is apparent from the above review that the Federal Court Judge throughout his analysis looked for more than possibilities understanding that mere possibilities were not enough, and that the prior art had to show more than that. His appreciation of the matter is summed up and further demonstrated by his concluding remarks (Reasons, para. 125):

Although there was a significant amount of evidence indicating that cGMP PDE inhibitors should be further explored with regards to the treatment of ED in the months leading up to the Pfizer discovery, the evidence does not in my view establish that the solution taught by the patent was obvious at the time. At best there was speculation, which in hindsight proved to be correct, that PDE5 inhibitors might treat impotence. Experiments with zaprinast, a cGMP PDE inhibitor, had been performed but in an effort to understand how the erectile process works, not how to treat ED. [My emphasis]

[37] In so holding, the Federal Court Judge drew the line precisely where the Supreme Court drew it in Sanofi-Synthelabo when it held that (para. 66) “the mere possibility that something might turn up is not enough”.

[43] The reasoning advanced by Mr. Justice Laddie and approved by the English Court of Appeal [in the corresponding U.K. case] is that where the motivation to achieve a result is very high, the degree of expected success becomes a minor matter. In such circumstances, the skilled person may feel compelled to pursue experimentation even though the chances of success are not particularly high.

[44] This is no doubt the case. However, the degree of motivation cannot transform a possible solution into an obvious one. Motivation is relevant in determining whether the skilled person has good reason to pursue “predictable” solutions or solutions that provide “a fair expectation of success” (see respectively the passages in KSR International Co. v. Teleflex Inc., 127 S. Ct. 1727 (2007) at page 1742 and Angiotech Pharmaceuticals Inc. v. Conor Medsystems Inc., [2008] UKHL 49, at paragraph 42, both of which are referred to with approval in Sanofi-Synthelabo, supra, at paragraphs 57 and 59).

[45] In contrast, the test applied by Mr. Justice Laddie appears to be met if the prior art indicates that something may work, and the motivation is such as to make this avenue “worthwhile” to pursue (Pfizer Ltd., supra, para. 107, as quoted at para. 42 above). As such, a solution may be “worthwhile” to pursue even though it is not “obvious to try” or in the words of Rothstein J. even though it is not “more or less self-evident” (Sanofi-Synthelabo, supra, para. 66). In my view, this approach which is based on the possibility that something might work, was expressly rejected by the Supreme Court in Sanofi-Synthelabo, at paragraph 66.

[46] The Federal Court Judge rendered his decision on the basis that more than possibilities were required. He concluded based on the evidence before him that Apotex had failed to establish more than that. In so doing, he applied the correct test.

[47] The appellant having failed to establish that either of the two alleged errors was committed, I would dismiss the appeal with costs. ...


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