Pfizer appealed from a decision of the Federal Court declaring
Pfizer's Canadian Patent No. 1,321,393 ( '393 Patent)
relating to the medicine amlodipine besylate (NORVASC) invalid for
Amlodipine is a calcium channel blocker and anti-hypertensive
compound, but had originally been formulated in the form of the
maleate salt. However, when problems with stability and
processability arose during the regulatory approval process, Pfizer
began to search for a different salt through an accepted process
known as salt screening. During this process, Pfizer tested seven
other salts, and decided to proceed with the besylate salt. Pfizer
then filed a patent application directed to the besylate salt of
amlodipine based on its alleged unique combination of properties
that made it particularly suitable for preparing formulations of
amlodipine. This application subsequently issued as the '393
In his decision, the trial judge discussed the development of
pharmaceutical products in the 1980's (particularly the salt
screening stage), detailed both the development of amlodipine
besylate and the patenting thereof, and thoroughly summarized all
expert evidence in relation thereto. The trial judge concluded that
the '393 patent was invalid for obviousness, as well as
finding, in obiter, that it was invalid on a number of other
grounds, including: lack of utility; insufficient disclosure;
misleading under s. 53 of the Patent Act; and that it failed to
meet the criteria for a valid selection patent. Pfizer appealed the
decision on both factual and legal grounds.
Regarding the alleged factual error, Pfizer asserted that the
trial judge erred in finding that a person skilled in the art
"would have had every reason to test the besylate salt."
Specifically, Pfizer argued that the trial judge erred by focussing
on the process the inventors used in developing the invention
rather than the outcome or result of the process. Pfizer submitted
that, when an invention is arrived at through testing, it is not
necessarily obvious merely because the utilized tests were within
the knowledge and capacity of the person skilled in the art.
Instead, according to Pfizer, the invention is obvious only if its
result was obvious. In this respect, Pfizer complained that its
cross-examination of one of ratiopharm's experts demonstrated
that the result was not obvious. The Court of Appeal summarily
dismissed Pfizer's argument, characterizing it as "a
complaint that the trial judge was insufficiently persuaded by
Pfizer's cross-examination". This did not demonstrate
palpable and overriding error.
Regarding the alleged legal error, Pfizer argued that the trial
judge misapplied the "obvious to try test" in an
obviousness inquiry. Specifically, Pfizer maintained that the trial
judge asked whether the process was more or less self-evident (or
predictable) when the appropriate question was whether the result
was self-evident (or predictable). Accordingly, in Pfizer's
view, the trial judge misdirected himself as to the law.
Furthermore, Pfizer argued that the trial judge erroneously relied
upon and adopted similar reasoning from U.S. authority on the same
issue. Again, the Court of Appeal rejected Pfizer's position,
stating that it was "a disguised attempt to challenge factual
determinations by characterizing them as errors of law."
Statements made by the trial judge regarding the U.S. decision were
in obiter, and the trial judge had explicitly recognized that
somewhat different principles applied in Canada. Consequently, no
legal or factual errors had been committed, and the appeal was
dismissed with costs.
The content of this article is intended to provide a general
guide to the subject matter. Specialist advice should be sought
about your specific circumstances.
To print this article, all you need is to be registered on Mondaq.com.
Click to Login as an existing user or Register so you can print this article.
A recent Saskatchewan Court of Queen's Bench decision allowed a court-appointed receiver to sell and transfer intellectual property rights free and clear of encumbrances, finding that a license to use improvements of an invention was a contractual interest and not a property interest.
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).