The case stems from May 2008, when the Commissioner of Patents refused to grant Bayer a patent to a pharmaceutical compound per se because a previous patent had already been issued to it for the same compound when made by a particular process (product-by-process patent). After Bayer's appeal to the Federal Court was dismissed, it appealed to the Federal Court of Appeal.
Bayer argued that "obviousness-type" double-patenting didn't apply to the situation at hand. However, the Federal Court of Appeal disagreed and dismissed the appeal, stating that: There is nothing inventive or "patentably distinct" in a claim for a product that is the subject of a previous process-dependent patent. On the other hand, a process-dependent patent may be granted, even though a patent has already been issued for the product itself, if the process claimed and described for making the product exhibits inventive ingenuity.
Consequently, the Commissioner correctly denied the Application on the ground of "obviousness" double patenting because the patent would have disclosed no new invention. For her to have granted a patent for the compound would have improperly "evergreened" the parent patent, now expired, by creating a second monopoly in the use of the compound running from the date when the Application was approved.
This decision puts an end to any disparity in the jurisprudence, as the Federal Court of Appeal effectively overruled the decision in Aventis Pharma Inc. v. Mayne Pharma (Canada) Inc., 2005 FC 1183, 42 C.P.R. (4th) 481, rev'd. on other grounds, 2008 FCA 21, 380 N.R. 35.