Viagra patent declared invalid by Supreme Court of Canada

November 8th, 2012 by Barry Sookman Leave a reply »

In an important case released today, Teva Canada Ltd. v. Pfizer Canada Inc. 2012 SCC 60, the Supreme Court of Canada ruled that Pfizer’s patent for its popular drug Viagra used for treating erectile dysfunction  was void for not meeting the disclosure requirements in s. 27(3) of the Patent Act.

To satisfy the disclosure requirements, the inventor must disclose his/her invention and describe how it works in the specification. In addition, the inventor must disclose in the specification  how “to make the same successful use of the invention as the inventor could at the time of his application”. These disclosure obligations are the quid pro quo for obtaining the monopoly right to make, use and sell the invention for the term of the patent.

Pfizer’s patent was ruled to be invalid because the specification did not indicate that sildenafil was the effective compound that worked. Having failed to disclose this essential information, the patent was declared invalid.

The Court commenced its analysis by going back to the fundamental principles underlying the patent system:

The issues in this appeal are best understood by reference to the fundamental principles underlying the patent system. As the courts below noted, sufficiency of disclosure lies at the very heart of this system. If the issues are viewed through this lens, the case becomes more straightforward, and the conclusion flows easily from this principle.

The patent system is based on a “bargain”, or quid pro quo: 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. This is the basic policy rationale underlying the Act. The patent bargain encourages innovation and advances science and technology…

Having set out the quid pro quo for obtaining a patent, the Court then explained why Pfizer’s patent specification failed to live up to the patent bargain:

As I noted above, this Court made it clear in Consolboard that the specification, which includes the claims and the disclosure, must define the “precise and exact extent” of the privilege being claimed so as to ensure that the public can, having only the specification, make the same use of the invention as the inventor (p. 520). In my view, the courts below misread Consolboard when they stated that the only questions that must be answered are “What is your invention?” and “How does it work?” Dickson J. did not state that those were the only relevant questions. In fact, quoting Minerals Separation, he went on to say, at p. 520: it ought to be getting in exchange for exclusive monopoly rights?

Recall that in this case Pfizer had conducted tests that demonstrated that sildenafil was effective in treating ED. None of the other compounds in Patent ’446 had been shown to be effective in doing so. Therefore, the invention was the use of sildenafil for the treatment of ED. This had to be disclosed in order to meet the requirements set out in s. 27(3) of the Act…

Although Patent ’446 includes the statement that “one of the especially preferred compounds induces penile erection in impotent males” (A.R., vol. X, at p. 173), the specification does not indicate that sildenafil is the effective compound, that Claim 7 contains the compound that works, or that the remaining compounds in the patent had been found not to be effective in treating ED. The claims were structured as “cascading claims”, with Claim 1 involving over 260 quintillion compounds, Claims 2 to 5 concerning progressively smaller groups of compounds, and Claims 6 and 7 each relating to an individual compound.

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”, because even if a skilled reader could have narrowed the effective compound down to the ones in Claim 6 and Claim 7, further testing would have been required to determine which of those two compounds was actually effective in treating ED. As the trial judge stated, at para. 146, “[a] skilled reader would then conduct tests on those two compounds and determine which of those compounds worked.” And as he also stated, at para. 135, “the skilled reader must undertake a minor research project to determine which claim is the true invention”.

Pfizer argued in the Court of Appeal that Teva had already been able to make the same use of the invention having only the specification, because it had filed a submission with the Minister of Health for a drug product containing sildenafil (F.C.A. reasons, at para. 48). However, this does not change the fact that the specification required, at a minimum, “a minor research project” in order to determine whether Claim 6 or Claim 7 contained the correct compound. The fact that Teva carried out this minor research project is irrelevant to Pfizer’s obligation to fully disclose the invention. More importantly, what must be considered is whether a skilled reader having only the specification would have been able to put the invention into practice. The trial judge clearly found that the skilled reader would have had to undertake a minor research project to determine what the true invention was.

Pfizer had the information needed to disclose the useful compound and chose not to release it…

It chose a method of drafting that failed to clearly set out what the invention was. Even now, in its factum to this Court, Pfizer offers no explanation as to why — knowing that Claim 7 contained the tested and thus, the useful, compound — it elected to withhold that information…

…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. The disclosure failed to state in clear terms what the invention was. Pfizer gained a benefit from the Act — exclusive monopoly rights — while withholding disclosure in spite of its disclosure obligations under the Act. As a matter of policy and sound statutory interpretation, patentees cannot be allowed to “game” the system in this way. This, in my view, is the key issue in this appeal. It must be resolved against Pfizer.

Print Friendly, PDF & Email
Advertisement
%d bloggers like this: