Disclosure Front and Centre as Pfizer Prepares to Defend Viagra in Supreme Court of Canada
April 15, 2012 by Sean JacksonThis Wednesday, April 18, Pfizer will defend the patent protecting the little blue pill that has changed the lives of men and women around the world. The pill is of course Viagra and the assailant is Teva, a generic pharmaceutical company. Teva applied for a Notice of Compliance in order to market a generic version of Viagra. In the application Teva alleged the patent covering Viagra (446 patent) was invalid for lack of utility, obviousness and insufficient disclosure. The Federal Court found that the 446 patent possessed utility, was not obvious, contained adequate disclosure and thus prohibited the Minister of Health from issuing a Notice of Compliance. The Federal Court of Appeal upheld this decision. Teva was granted leave to appeal to the Supreme Court of Canada (SCC).
At first glance this may appear as another case involving a generic pharmaceutical company attempting to gain a share of the market for a successful brand name drug. After reading the factums of both sides and examining the issues more closely it becomes clear that there is much more at stake and the decision could have important implications for the patent system as a whole.
One of the central arguments being advanced by Teva is that the 446 patent is invalid based on insufficient disclosure. Section 27(3)(a) of the Patent Act states, “The specification of an invention must … correctly and fully describe the invention and its operation or use as contemplated by the inventor.” This requirement strikes directly at the heart of the patent bargain theory, namely, that in exchange for a limited term monopoly the patentee must completely disclose the invention to the public so that it may practice the invention once the patent has expired.
The disclosure of Pfizer’s 446 patent explains that the invention relates to the use of a compound of formula (I) or a salt thereof in the treatment of erectile dysfunction. The first claim describes formula (I), which gives rise to 260 quintillion possible compounds. The following four claims are for progressively smaller ranges of compounds while claims 6 and 7 each pertain to a single compound.
Teva’s disclosure argument relies on the following facts: (1) that neither the disclosure nor the claims state that claim 7 contains sildenafil citrate, the compound marketed and sold as Viagra; (2) that sildenafil citrate is the active compound; and (3) that despite Pfizer’s knowledge, it was not disclosed that the remaining compounds in the patent had not been found to treat erectile dysfunction. Teva contends that because, as of the patent filing date, Pfizer knew that sildenafil citrate was the only effective compound, they were required by law to disclose this in the patent. Instead of doing this, Teva asserts that Pfizer artfully worded the patent so as to hide the true identity of its active compound from the public.
In essence, Pfizer counters by stating a patent specification includes both the descriptive portion and the claims and since an invention is defined by the claims it has met the statutory requirements of disclosure by claiming sildenafil citrate as a single compound in claim 7 of the 446 patent.
In addition to seeing how the SCC deals with the disclosure issue it will be interesting to see how, if at all, the SCC handles the policy implications that are at stake. Should the Court rule in favor of Pfizer and hold that the disclosure of the 446 patent is sufficient the decision could signal a green light for clever patent lawyers and agents to skillfully draft patents so as to hide crucial information from the public (and competitors) thereby giving the patentee a slight advantage in what can be extremely competitive marketplaces. As such, there will be much more than a share of the erectile dysfunction marketplace at stake when the SCC decides the fate of the Viagra patent.
Sean Jackson is a JD Candidate at Osgoode Hall Law School.
4 Responses to “Disclosure Front and Centre as Pfizer Prepares to Defend Viagra in Supreme Court of Canada”
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Indeed, I recently canvassed the importance of this case in the May issue of the Journal of Intellectual Property Law & Practice (available here: http://jiplp.oxfordjournals.org/content/7/5/302.short?rss=1).
The Canadian Patent Rules have the same force & effect as if they had been enacted in the Patent Act (PA, s 12(2)). Rule 79 requires, in subs. (2), that the patent’s abstract to contain “a concise summary of the matter contained in the application and, where applicable, the chemical formula that, among all the formulae included in the application, best characterizes the invention.” There is more in Rule 79 along the same lines. I wonder how it is thought that the Viagra patent’s abstract can possibly comply with this rule, and whether, if it does not, Rule 79 is a provision for which non-compliance is a “fact or default which by this Act or by law renders the patent void” (PA, s 59). Here is the abstract:
“The use of a compound of formula (I) wherein R1 is H; C1-C3 alkyl; C1-C3 perfluoroalkyl; or C3-C5 cycloalkyl; R2 is H; optionally substituted C1-C6 alkyl; C1-C3 perfluoroalkyl; or C3-C6 cycloalkyl; R3 is optionally substituted C1-C6 alkyl; C1-C6 perfluo-roalkyl; C3-C5 cycloalkyl; C3-C6 alkenyl; or C3-C6 alkynyl; R4 is optionally substituted C1-C4 alkyl, C2-
C4 alkenyl, C2-C4 alkanoyl, (hydroxy)C2-C4 alkyl or (C2-C3 alkoxy)C1-C2 alkyl; CONR5R6; CO2R7; halo; NR5R6; NHSO2NR5R6; NHSO2R8; SO2NR9R10; or phenyl, pyridyl, pyrimidinyl, imidazoyl, oxazolyl, thiazolyl, thienyl or triazolyl any of which is optionally substituted with methyl; R5 and R6 are each independently H or C1-C4 alkyl, or together with the
nitrogen atom to which they are attached form an optionally substituted pyrrolidinyl, piperidino, morpholino, 4-N(R11)-piperazinyl or imidazolyl group; R7 is H or C1-C4 alkyl; R8 is optionally substituted C1-C3 alkyl; R9 and R10 together with the nitrogen atom to which they are attached form an optionally substituted pyrrolidinyl, piperidino, morpholino or 4-N(R12)-piperazinyl group; R11 is H; optionally substituted C1-C3 alkyl; (hydroxy)C2-C3 alkyl; or C1-C4 alkanoyl; R12 is H; optionally substituted C1-C6 alkyl; CONR13R14; CSNR13R14; or C(NH)NR13R14; and R?13? and R14 are each independently H; C1-C4 alkyl; or substituted C2-C4 alkyl; or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition containing either entity, for the manufacture of a medicament for the curative or prophylactic
treatment of erectile dysfunction in a male animal, including man; a pharmaceutical composition for said treatment; and a method of said treatment of said male animal with said pharmaceutical composition or with said either entity.”
[...] Viagra (Sildenifil) – Canada: Disclosure front and centre as Pfizer prepares to defend Viagra in Supreme Court of Canada (IP Osgoode) [...]
Exciting update to this case! The Supreme Court of Canada rules Pfizer’s patent is invalid: http://www.iposgoode.ca/?p=19156