In the  Supreme Court decision of Teva Canada Ltd. v. Pfizer Canada Inc. 2012 SCC 60 – Nov 8, 2012 –  (Decision varied by SCC in 2013 from pronouncement that patent is not valid to “Teva has established its allegation that Canadian Patent 2,163,446 is not valid) the validity issue of the Viagra patent turned on the patent bargain not being met.

The court set out the patent bargain in recognizing:  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. Sufficiency of disclosure lies at the very heart of the patent system, so adequate disclosure in the specification is a precondition for the granting of a patent.

Some points to consider from this decision are:

• Pfizer CA 2,163,446 patent (‘446 patent) is for the use of a “compound of formula (I)” or a “salt thereof” as a medical treatment of erectile dysfunction (“ED”).
• The ‘446 patent ended with cascading claims.  The court reviewed the claims with the view that the useful claim will usually be at the end concerning an individual compound.  However, the cascading claims ended with two separately claimed compounds – one of which was sildenafil and the other to a compound that did not work.
• The patent disclosure listed 10 “especially preferred compounds”, one of which was sildenafil – so the claim to the compound sildenafil was fully supported.
• The patent also stated that “one of the especially preferred compounds” induces penile erection in impotent males” and did not further elaborate as to which one of the compounds was the compound that worked.  At the time of filing the patent application, sildenafil was known to be the compound effective in inducing penile erection in impotent males.
• Even if the claimed subject matter is supported by the disclosure, if the disclosure lacks in its teaching, the claim is invalid.
• The specification as a whole, which includes the claims and the disclosure, determines whether the patent meets the disclosure requirements.
• The disclosure in the specification would not have enabled the public “to make the same successful use of the invention as the inventor could at the time of his application.”
• The patent disclosure does not indicate that sildenafil is the effective compound.
• As far as the cascading claims ending in 2 claims each claiming a compound, one of which is sildenafil, further testing would have been required for a skilled person to determine which of those two separately claimed compounds was actually effective in treating ED.
• The public’s right to proper disclosure was denied in this case, since the claims ended with two individually claimed compounds, thereby obscuring the true invention.
• As a matter of policy and sound statutory interpretation, patentees cannot be allowed to “game” the system in this way.

Take Aways

• Conclusion……Don’t game the system – Don’t hide the invention – disclose what works.
• A subsequent lower court decision when considering issue of sufficiency of the disclosure distinguished from SCC ruling in finding that there was no “gaming” present.