P holds Patent 2,163,446 for the use of a “compound of formula (I)” or a “salt thereof” as a medicament for the treatment of erectile dysfunction (“ED”). The patent’s specification ends with seven cascading claims for successively smaller ranges of compounds, with Claims 6 and 7 relating to a single compound each. Only sildenafil, the subject of Claim 7 and the active compound in Viagra, had been shown to be effective in treating ED at the time of the patent application. Although the patent includes the statement that “one of the especially preferred compounds induces penile erection in impotent males”, the patent application does not disclose that the compound that works is sildenafil, that it is found in Claim 7, or that the remaining compounds had not been found to be effective in treating ED.

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The patent application did not satisfy the disclosure requirements set out in the Patent Act, R.S.C. 1985, c. P‑4 (“Act”). 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.

The ruling goes back to this all-important concept a few times: without disclosure, there can be no patent. It's good to see the court making this a central point, because pharma companies are notorious for attempting to twist the patent system so they get virtually perpetual monopolies on their drugs, while still shrouding their research and manufacturing methods in as much secrecy as possible. In the US, Pfizer had a similar showdown with Teva over generic Viagra starting in 2010, in which Pfizer won using a second patent that didn't cover the active compound in Viagra itself, but rather the marketing of it as an erectile dysfunction drug. Thus, even though the core patent on the drug expired this year, Pfizer will likely retain a monopoly on it until 2019. This is in stark contrast to the UK, where the patent on using the drug to treat ED was invalidated for obviousness way back in 2000—but Pfizer still dominates the market there thanks to related patents on manufacturing methods.

Basically, Pfizer uses any method it can think of to prevent its patents from ever expiring and benefiting the public the way patents are supposed to, including writing disclosures that obscure the necessary facts. The Supreme Court was having none of it—rather than letting Pfizer retroactively fix the disclosure, or coming up with any kind of partial remedy that allowed them to retain the patent, the ruling correctly states that patents must be a deal between two sides to function, and thus the patent is (and always has been) invalid:

Although s. 27 does not specify a remedy for insufficient disclosure, the quid pro quo underpinning the Act leads to the conclusion that deeming the patent invalid is the logical consequence of a failure to properly disclose the invention and how it works. If there is no quid — proper disclosure — then there can be no quo — exclusive monopoly rights.

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There is no question that sildenafil’s utility had been demonstrated as of the time of filing of the patent application. This takes the invention out of the realm of sound prediction. As to the delay of 13 years between the filing of the patent and the challenge, the relevant question is whether the disclosure was sufficient as of the date of filing, so the delay is inconsequential.

This is a big victory for Teva and a major blow to Pfizer's Viagra empire, which is slowly crumbling around the globe. It's also likely to lead to even more illegal cross-border pharma sales, and even more of everyone's favorite email spam advertising online Canadian pharmacies—but that's another story.