On November 8, 2012 the Supreme Court of Canada (SCC) released its eagerly anticipated decision in the “Viagra Appeal”. In a unanimous decision written by Justice LeBel, the SCC found the patent at issue invalid for insufficient disclosure. This decision marks the end of a lengthy legal battle between Teva and Pfizer over the validity of Canadian Patent 2,163,446 (the “446 Patent”).

Sildenafil, the medicinal ingredient in Viagra, was initially pursued for its use in treating hypertension and in 1998 Pfizer received a patent claiming sildenafil and its use in treating hypertension and angina. Serendipitously, when testing sildenafil on male patients, it was observed that some patients experienced spontaneous erections. A subsequent study confirmed the result with sildenafil and Pfizer applied for a second patent claiming the use of sildenafil in the treatment of ED. Pfizer received the 446 Patent on July 7, 1998.  In 2007, Teva applied for a Notice of Compliance in order to market a generic version of Viagra. Pfizer responded by bringing a proceeding in the Federal Court for an order prohibiting the Minister of Health from granting approval until expiry of the 446 Patent. Teva alleged the 446 Patent was invalid for insufficient disclosure, obviousness and lack of utility. The Federal Court found the 446 Patent sufficiently disclosed the invention, was not obvious, had utility and prohibited the Minister of Health from issuing a Notice of Compliance. On appeal, the Federal Court of Appeal upheld the Federal Court's decision. Teva, unwavering in its belief that Pfizer’s Viagra monopoly was based on an invalid patent, sought and was granted leave to appeal to the SCC.

The main issue on appeal to the SCC was the sufficiency of the 446 Patent’s disclosure. The 446 Patent discloses that the invention relates to the use of a group of compounds in the treatment of ED.  Despite the fact that sildenafil was the only compound that Pfizer had tested and demonstrated to induce erections, Pfizer artfully drafted the patent to cover an estimated 260 quintillion compounds, effectively hiding the true invention. As described by Teva, Pfizer grew a forest to hide the leaf that was sildenafil.

Teva’s argument before the SCC was simple. In failing to disclose the identity of sildenafil as the only effective compound, Pfizer’s patent failed to fully and correctly disclose the invention as is required by s. 27(3) of the Patent Act.  Teva argued that by not disclosing the identity of sildenafil, the patent did not place the public in the same position as the patentee and forced the reader to embark on a minor research project to identify the true invention. The factums of both parties can be found here.

The SCC agreed with Teva’s argument and stated “the public’s right to proper disclosure was denied in this case” and that the patent obscured the true invention. Justice LeBel wrote that as a matter of policy and sound statutory interpretation, patentees cannot be allowed to “game” the system in this way. The Court reiterated that the patent system is based on a “bargain”, the inventor is granted exclusive rights in a new and useful invention for a limited period in exchange for disclosure of the invention so that society can benefit from this knowledge. Justice LeBel stated that in this particular case, the disclosure failed to enable the public to make the same successful use of the invention as the inventor could at the time of his application, because it failed to indicate that sildenafil is the effective compound.

While it is far too early to conclude what impact this decision will have on Canadian patent law, several interesting implications emerge immediately. First, the decision paves the way for affordable generic Viagra to enter the Canadian marketplace. Secondly, the decision clarifies the disclosure requirement and ensures (hopefully) that patentees will not be able to “game” the patent system to hide their true inventions while retaining the benefits. Finally, it is interesting to note that in a proceeding aimed solely at determining whether the Minister of Health is permitted to issue a Notice of Compliance, the SCC provided the remedy of ruling the 446 Patent invalid. While only father time will reveal the full implications of this decision, it will undoubtedly help ensure the Canadian public receives a fair exchange in patent bargains.

Sean Jackson is a third year J.D. Candidate at Osgoode Hall Law School. A more detailed review of this case will appear in an upcoming edition of the Intellectual Property Journal (IPJ).