The Federal Court released reasons, dated November 3, 2015, for dismissing Amgen’s application for an order prohibiting the Minister of Health from issuing a notice of compliance to Mylan for its cinacalcet tablets (Amgen’s SENSIPAR): Amgen Canada Inc v Mylan Pharmaceuticals ULC, 2015 FC 1244. Mylan alleged that Canadian Patent No. 2,202,879 (879 patent) was not a valid selection patent and was anticipated, obvious, and invalid for double-patenting. The Court issued a judgment dismissing the application on October 19, 2015, with reasons to follow, so as to avoid any lack of jurisdiction arising from the expiry of the 879 patent on October 23, 2015. The Court held that none of Mylan’s allegations were disproven by Amgen.
Cinacalcet was part of a genus of previously claimed compounds
In the early 1990s, researchers at NPS Pharmaceuticals, Inc. (NPS) discovered a large family of compounds that mimicked the effect of extracellular calcium on the parathyroid calcium-sensing receptor (CaSR). It was thought that these compounds would reduce the secretion of parathyroid hormone, leading to lower extracellular calcium levels. In 1992, NPS claimed this family of compounds, which included cinacalcet, in a patent application that became Canadian Patent No. 2,115,828 (828 patent). In 1993, the “WO 959” application was filed, disclosing an essentially identical genus of compounds.
The 879 patent asserted by Amgen was filed by NPS on October 23, 1995. It claims trillions of compounds, with preferred compounds that mimic or block the effect of extracellular calcium on the CaSR. The only claim at issue was claim 5 for cinacalcet and its pharmaceutically acceptable salts and complexes.
NPS did not actually focus on cinacalcet until 1996, in part because its research team was wary of compounds with naphthyl functional groups. SENSIPAR was later approved for the treatment of a number of human disorders characterized by abnormally high extracellular calcium levels. The 828 patent expired in 2012.
The 879 patent was not a selection patent and claim 5 was not a selection invention
Amgen acknowledged that cinacalcet was disclosed in the 828 patent and WO 959 application, but asserted that claim 5 of the 879 patent was a selection invention. The Court rejected this submission as Amgen had failed to establish a substantial and unexpected advantage, either qualitative or quantitative, over the previously disclosed genus in respect of either the 879 patent as a whole or with respect to claim 5 in particular.
On the qualitative ground, the Court held that the actual mechanism by which the process works (CaSR was detecting and signaling extracellular calcium levels in the parathyroid gland) and the target upon which cinacalcet acts (the CaSR) was the same as what the inventors had expected in the 828 patent and there was nothing surprising about its potency.
On the quantitative ground, 47 of the 61 compounds listed in a table in the 879 patent caused a larger increase in intracellular calcium levels (a downstream effect of CaSR signaling) than cinacalcet did and such potency fell within the range identified in the 828 patent.
Thus, the Court found there was no substantial and unexpected advantage, and no advantage was even described in the 879 patent.
The Court found that the requirements for a selection were not otherwise met, including as “nothing in the 879 Patent singles out Cinacalcet.” As the 879 patent was not a selection patent, and claim 5 was not a selection invention, the Court found that Amgen had “failed to establish that its patent is novel” (paragraphs 77 and 78).
Claim 5 of the 879 patent was anticipated
The Court analyzed anticipation separately from the selection patent issue. The Court concluded that the 828 patent application and the WO 959 application, both of which had been published before the 879 patent application, disclosed and enabled cinacalcet. The Court found particularly persuasive Mylan’s expert evidence that there was no inventive step to get from the 828 patent to cinacalcet, as only mechanical testing of at most 200 preferred compounds in the 828 patent would have been required.
Claim 5 of the 879 patent was obvious, obvious to try, and the result of obviousness-type double patenting
The Court found that the 828 patent and WO 959 also made claim 5 of the 879 patent obvious. Conducting the four-step Sanofi analysis, the Court found that the inventive concept of claim 5 was cinacalcet per se and not cinacalcet’s activity as a CaSR modulator, as the latter had been described in the 828 patent. There was no difference between the inventive concept of claim 5 and the prior art, as the published 828 patent application and WO 959 application had disclosed cinacalcet’s structure and function.
The Court found further that, if there was a difference between claim 5 and the state of the art, it was obvious to try to obtain cinacalcet as a CaSR modulator. Again, the Court relied on Mylan’s expert evidence that the “preferred claims” in the 828 patent identified at most 200 compounds to test further as part of “routine development”. This “easy and mechanical” process would have verified that cinacalcet acted on the CaSR and that its potency fell within the range set out in the 828 patent (paragraphs 38 and 93-95). In addition, the skilled person would not share the bias that NPS’s research team had against naphthyl functional groups. Therefore, NPS’s delay in arriving at cinacalcet did not gainsay the Court’s finding that cinacalcet was obvious to try. Lastly, with respect to Mylan’s allegation of double patenting, the Court found that, in the light of the findings on obviousness, claim 5 was not patentably distinct from the 828 patent.
The Court decided the application on October 19, 2015 and Mylan received its notice of compliance on that date. The 879 patent expired on October 23, 2015. Amgen did not appeal.
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