If There is No Quid Then There Can Be No Quo - Pfizer's Viagra patent invalidated by Supreme Court of Canada

By Suzanne Hof - November 2012

cb photo_91_4f19cd1eeada2Today, in a unanimous decision, the Supreme Court of Canada sided with Teva Canada Limited in its bid to invalidate Pfizer Canada Inc.’s Canadian Patent No. 2,163,446 (the ‘446 patent), thereby clearing the way for generic companies to manufacture and sell a generic version of the multi-million dollar erectile dysfunction (ED) drug, Viagra.

This decision hinged on the finding that the ‘446 patent did not satisfy the disclosure requirements under Section 27(3) of the Patent Act. In this regard, the Supreme Court overturned the findings of both the Federal Court and the Federal Court of Appeal that the ‘446 patent did, in fact, provide sufficient disclosure.

The question of sufficiency was raised around whether the specification would have enabled the public “to make the same successful use of the invention as the inventor could at the time of his application” because it does not indicate that sildenafil (the active compound in Viagra) is the effective compound. Although the ‘446 patent does state that “one of the especially preferred compounds induces penile erection in impotent males,” there is no indication which of the several specific compounds identified throughout the description of the patent is this “especially preferred” compound, i.e., sildenafil. Nor does the specification state that the remaining compounds identified in the ‘446 patent were found not to be effective in treating ED.

Furthermore, although claims 6 and 7 are each directed to specific single compounds, there is no indication in the specification that claim 7 relates to sildenafil. By omitting any clear statement that the sildenafil is the active compound, the Supreme Court found that:


There was no basis for a skilled person to determine which of Claim 6 and Claim 7 contained the useful compound, further testing would have been required to determine which of those two compounds was actually effective in treating ED.


According to fundamental principles underlying the patent system, adequate disclosure of the invention in the specification is a precondition for the granting of a monopoly to an invention. It is this “bargain”, or quid pro quo, that the Court references (“[i]f there is no quid – proper disclosure – then there can be no quo – exclusive monopoly rights”) in its finding that the patent be deemed invalid.


If you have any questions please contact Suzanne Hof

Please read the UPDATE on this in our on Nov 16, 2012 NEWSFLASH - Supreme Court Asked to Reconsider Decision to Invalidate Viagra Patent


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