The appellants (Sanofi-Aventis and Schering Corporation) appealed a motion judge's decision dismissing their motion to amend their statement of defence.
The appellants sought to plead that a 2009 Federal Court decision invalidating their patent for the drug Ramipril was based on wrong legal principles, specifically the "promise doctrine," which was subsequently struck down by the Supreme Court of Canada in 2017.
The motion judge had dismissed the motion on the basis of issue estoppel, finding no change in law justified departing from the doctrine.
The Court of Appeal allowed the appeal, holding that the Supreme Court's decision striking down the promise doctrine constituted a change in law that warranted exercising discretion not to apply issue estoppel, particularly given the centrality of the patent validity issue to the respondent's claim for damages.
