Skip to main content

After Reconsideration, the Viagra™ Patent is not Void

Reading Time 3 minute read


Technology and Intellectual Property Bulletin

Close to seven months after rendering its decision in Teva Canada Ltd v Pfizer Canada Inc., 2012 SCC 60, the Supreme Court of Canada varied its decision on Tuesday, June 4, 2013, to remove all references to the Sildenafil patent being "invalid" or "void". Instead the Court decided to affirm Teva's allegation of invalidity of the Viagra™ patent pursuant to the Patented Medicines (Notice of Compliance) Regulations ("PM(NOC) Regulations"). The distinction between whether an allegation of invalidity is justified under the Patent Act versus a declaration of invalidity pursuant to the PM(NOC) Regulations, while subtle, is material.

Last November, the Supreme Court declared Pfizer's patent on Sildenafil (the active ingredient in Viagra™) invalid for insufficient disclosure contrary to section 27(3) of the Patent Act despite the proceedings having been brought under the PM(NOC) Regulations. In voiding the patent, there has been some debate as to whether the Court "accidentally" granted a remedy that exceeded its jurisdiction.

By way of background, proceedings commenced under the PM(NOC) Regulations are distinct from patent infringement actions. At their core, these applications consist of disputes between a generic and innovator drug manufacturer about whether the Health Minister may issue market approval to sell a generic version of an approved patented drug. The PM(NOC) Regulations do not contemplate proceeding by way of action nor do they provide for a final determination of issues of validity or infringement of a patent. Rather, proceedings under the PM(NOC) Regulations are applications of judicial review and are intended to be summary in nature. A declaration of invalidity of a patent under the PM(NOC) Regulations only speaks to whether a generic's allegation of invalidity is justified within the application. It does not void the patent for the purposes of the Patent Act.  The Federal Court has repeatedly affirmed that parties continue to enjoy the ability to litigate patent issues in actions, independent of proceedings under the PM(NOC) Regulations.

In the days following the decision, Pfizer brought a motion for re-hearing, to vary the Supreme Court's decision. Pfizer alleged that the underlying proceeding was an application under the PM(NOC) Regulations where, as mentioned, the Court could only determine whether allegations of invalidity and non-infringement by Teva were justified. Pfizer argued that the Supreme Court did not have jurisdiction to "invalidate" or "void" the Viagra™ Patent. Instead, the Court's order under the PM(NOC) Regulations  should have simply set aside the prohibition by the Minister of Health to issue market approval to Teva for the sale of their own version of Sildenafil.

Thankfully, the Court varied its decision restoring some order to the Canadian patent and regulatory regime. As of last Tuesday, Pfizer's patent for Sildenafil is no longer invalid nor void as it relates to these original proceedings. However, since the November decision by the Supreme Court, the Federal Court has declared the Sildenafil patent invalid in an impeachment action brought by Apotex pursuant to the Patent Act (see Apotex Inc v Pfizer Ireland Pharmaceuticals, 2012 FC 1339 – decision appealed).

Had the Court declined to amend its judgment, future motions under these PM(NOC) Regulations would have provided a short cut for generic manufacturers to invalidate patents. Nevertheless, in light of the confusion of the Court in these proceedings, some patentees, as a precautionary measure, may decide to seek a declaration of validity for their patents in order to safeguard their inventions.

Contact the Author

For more information or to discuss a particular matter please contact us.

Contact the Author



    Receive email updates from our team