Canada: Federal Court Of Appeal Affirms Prohibition Order Against Apotex Regarding Abiraterone

As previously reported, in the final decision released under the pre-amended Patented Medicines (Notice of Compliance) Regulations (Regulations), the Federal Court granted a prohibition order relating to Canadian Patent No. 2,661,422 (422 patent), Apotex, and its abiraterone acetate product (Janssen's ZYTIGA). Apotex appealed.

In subsequent separate actions under the amended Regulations brought against Apotex, Dr. Reddy's Laboratories, and Pharmascience (reported here), the Federal Court found the 422 patent invalid on the basis of obviousness and dismissed the actions (Janssen has appealed). As a result, the Minister issued an NOC to Apotex rendering the first appeal moot; however, the Court of Appeal (FCA) exercised its discretion to hear the appeal, as the outcome could affect section 8 damages. On March 4, 2021, the FCA affirmed the decision granting the prohibition order: Apotex Inc v Janssen Inc, 2021 FCA 45.

This article addresses the 2021 appeal decision. The 422 patent concerns the treatment of prostate cancer by administering abiraterone acetate (AA) in combination with prednisone (PN). The FCA examined issues of patentable subject matter, obviousness, inutility and infringement, as set out below.

Patentable Subject Matter

The trial judge held that the 422 patent claims patentable subject matter because the combination achieves an anti-cancer effect greater than with either drug alone. Apotex argued that the validity of a patent for a combination requires synergy – that the result be different from the sum of the result of the elements. However, the FCA found that the key consideration for patentability of a combination was whether the combination offers something that was not available to the public. As there was no dispute that the combination of AA and PN provided improved results than what was previously known, the FCA found the combination claimed patentable subject matter.

Obviousness

The FCA was not convinced that the trial judge made a reviewable error in the obviousness analysis. While the trial judge made observations about elements beyond the scope of the claims, such as that neither AA nor PN had shown a survival benefit, this was not a reviewable error. The trial judge was not defining the differences between the invention and the state of the art, but rather describing some characteristics of it.

The FCA found that the trial judge considered each of the factors relevant to obviousness to try and reached a conclusion based on that consideration.

The FCA found that the trial judge considered each of the factors relevant to obviousness to try and reached a conclusion based on that consideration. The FCA also commented on the obvious to try test, stating that despite some mixed signals from the Supreme Court of Canada, "more or less self-evident that it ought to work" should be treated as a factor in the obvious to try analysis, and not as a requirement, as previously explained by the FCA (see article here).

Inutility

The FCA found no palpable or overriding error in the trial judge's determination that utility of the 422 patent was demonstrated. The FCA observed that testing must be considered cumulatively; that it is not necessary that tests conclusively prove the requisite utility; and that it is sufficient that the test results are strongly suggestive of utility and that no other logical explanation for the test results is likely.

Apotex argued that since prostate specific antigen (or PSA, the measure used in the testing conducted) was a surrogate measure for effectiveness of prostate cancer treatments rather than a direct measure, the results merely provided a factual basis for prediction of utility rather than demonstration. However, the FCA found no error, given the general agreement that a PSA level indicates the response to prostate cancer treatment, combined with the vagueness of the line between demonstration of utility and a prediction of utility.

Infringement

As the 422 patent claimed the combination of AA and PN in the treatment of prostate cancer, and Apotex was proposing to market AA only, Janssen only argued that Apotex would induce infringement. Apotex argued that infringement required that both components of the combination contribute meaningful anti-cancer effects, but Apotex's product monograph contemplated prednisone for its palliative effects.

The FCA rejected this assertion, finding that the trial judge found that both components of the combination will contribute meaningful anti-cancer effects, and that direct infringement will inevitably result from the use of the combination as contemplated in the product monograph.

As Apotex's product monograph contemplated all of the essential elements of the patented combination, the FCA found that Apotex's inducement of the use of the infringing combination, together with its knowledge that its influence will result in the use of that combination, was sufficient to find inducement of infringement.

Should you have any questions, please do not hesitate to contact a member of the Pharmaceutical Litigation Group.

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