The Federal Court released its reasons in Amgen Canada Inc v Mylan Pharmaceuticals ULC on November 3, 2015.The Court dismissed an application commenced under the Patented Medicines (Notice of Compliance) Regulations(NOC proceeding) by pharmaceutical company Amgen for an order prohibiting the Minister of Health from issuing a market authorization (notice of compliance) to Mylan for its version of Amgen’s calcimimetic drug SENSIPAR®.   These reasons are a rare instance of the Federal Court invalidating a patent covering a chemical compound on prior art grounds. The Court’s judgment also serves as a reminder that verifying the predicted properties of previously disclosed compounds is undeserving of a patent.


Canadian Patent No. 2,202,879 (the 879 Patent) disclosed and claimed a very large number of compounds, including the cinacalcet molecule and its pharmaceutically acceptable salts.  Claim 5 was directed to cinacalcet, the medicinal ingredient in SENSIPAR®.

Mylan alleged that the 879 Patent was invalid for anticipation, obviousness and obviousness-type double patenting.  Amgen acknowledged in the NOC proceeding that a prior art patent (the 828 Patent) disclosed cinacalcet generically as part of a claimed genus of over a trillion structures, but Amgen argued that because the inventors of the 828 Patent had neither made nor tested cinacalcet, claim 5 of the 879 Patent was the “selection invention” of cinacalcet from the compounds disclosed in the 828 Patent.  This selection, Amgen argued, was the “complete answer” to Mylan’s invalidity allegations.  

Cinacalcet Not a Selection Invention

The Federal Court disagreed that cinacalcet and the 879 Patent as a whole were selection inventions.  Justice Phelan reiterated that a selection patent does not differ from any other type of patent, but he held that neither the 879 Patent nor evidence submitted by Amgen supported that the invention of the 879 Patent was a selection: cinacalcet simply did not differ qualitatively or quantitatively from other compounds disclosed in the 828 Patent.  In so doing, the Federal Court reaffirmed the principle that it is not an invention to make and test compounds that were previously disclosed, even generically or as part of an enormous class, if the selected species do not have unique and unexpected properties.


Having found that cinacalcet did not have novel properties, the Federal Court held that the prior art 828 Patent anticipated claim 5 of the 879 Patent.  Relying extensively upon Mylan’s experts, the Court concluded that there was no inventive difference between the 828 Patent and cinacalcet.  Mylan’s experts had opined that a skilled person would have made cinacalcet “as part of a routine development based solely on the teaching of the 828 Patent.”  Specifically, the skilled person had to synthesize and test at most 200 compounds to arrive at cinacalcet, and this testing was mechanical.  On these grounds, the Court concluded that cinacalcet was not novel over the class of compounds disclosed in the prior art.    


On the issues of obviousness and obviousness-type double patenting, the Federal Court held that cinacalcet was not inventive and that claim 5 was not patentably distinct from the invention previously disclosed in the 828 Patent.  Relying again on Mylan’s experts, the Court concluded that it would have been obvious to try to obtain cinacalcet because a skilled person would only need to make and test 200 compounds which, on the evidence, was easy and mechanical.  The simple verification that cinacalcet had the properties described or predicted in the prior art did not make it inventive.

Practical Implications

Practically speaking, Amgen Canada v Mylan Pharmaceuticals ULC highlights the crucial role that expert evidence plays in the Court’s assessment of prior art disclosures.  The Court’s reasons also confirm that the generic disclosure of compounds as part of a large prior art class will anticipate the alleged invention of a compound within that class, unless the claimed compound has unique and unexpected properties.  Moreover, the Federal Court’s conclusion on the evidence that making and testing 200 compounds was simple and mechanical illustrates that an alleged invention may be obvious to try, and ultimately uninventive, if it only involves verifying predicted properties through well-known and easy tests.   

Read the Federal Court Reasons for Judgment [PDF].