Pfizer Canada et al. v.
Pfizer brought an application under
the PM(NOC) Regulations to prohibit the Minister of Health from issuing
a Notice of Compliance to Pharmascience in respect of its PMS-Pregabalin
capsules until the expiry of Canadian Patent No. 2,255,652 ('652 patent).
In accordance with the Regulations,
Pharmascience had served Pfizer with a Notice of Allegation dated February 11,
2011, alleging that the '652 patent is invalid on a number of grounds including
insufficiency, inutility due to lack of sound prediction, and obviousness. The
parties agreed that only claim 3 of the '652 patent was at issue.
Application is dismissed.
The Court found that claim 3
“For use in treating pain, in a
mammal, a therapeutically effective amount of pregabalin or its racemate.”
First, the Court construed the word
“pain”. The Court summarised rules of claim construction, followed Free
World Trust v Électro-Santé Inc.,  2 SCR 1024, and endeavoured to
construe “pain” in the context of that claim in an informed and purposive way.
The Court examined the claims and
the description, and held that the meaning of “pain” as found in claim 3 of the
'652 patent is broad. It encompassed all of the specific pains claimed in
claims 4 to 16, and all of the specific pains mentioned in relevant portions of
the description. When the pains listed were broadened by the words “…but not
limited to”, the broadening would be limited to those pains that, as of the
laid-open date, would be reasonably related to the named pains.
Insufficiency – Claims Broader than
the Invention Made or Disclosed
Pharmascience’s allegation that
claim 3 of the '652 patent is invalid as being broader than the invention made
or disclosed is justified.
The evidence showed that the
inventor never tested or contemplated the testing of the racemate included in
claim 3. The inventor stated that pregabalin is useful only in respect of
chronic or persistent pain, not acute pain. The Court disagreed with Pfizer’s
argument that the effectiveness of the racemate can be inferred as predicted
from the disclosure of the patent.
The Court found the description
insufficient to support use of pregabalin and its racemate in acute pain and
the use of the racemate in any sort of pain relief.
Inutility – Lack of Sound Prediction
Claim 3 is invalid in that it
embraces pain which cannot be treated, as well as pain which, as of the
Canadian filing date, could not have been predicted as treatable by pregabalin.
The Court recited a detailed history
of the jurisprudence on sound prediction, concluding with the recent SCC
decision in Viagra (2012 SCC 60). The Court found that the SCC in Viagra
expressly left the question of sound prediction open for another day, and that
the law as expressed by that Court in AZT and followed by the FC and FCA
is still good law.
The basis for sound prediction, at
least in respect of a pharmaceutical, must be disclosed in the descriptive part
of the patent.
There was no factual basis and no
line of reasoning set out in the '652 patent from which a person skilled in the
art could make a sound prediction that the racemate would be useful in treating
the variety of pain encompassed by claim 3 or even some of them.
Pharmascience’s allegation as to
obviousness is not justified.
The Court applied the Sanofi
test set out by the SCC:
In step 2 of the test, the Court
found that the inventive concept of claim 3 is not simply that pregabalin can
be used to treat some types of pain. The inventive concept is that pregabalin
or its racemate can be used to treat a variety of types of pain.
In step 4, the Court held that the
difference between the “state of the art” and the inventive concept was not
obvious because while anticonvulsants were looked at as a fruitful field to try
and see if any of them worked with respect to pain, one would not know, until
it was tested, whether it worked in fact, and without any harmful effects.
Although the patent bargain is not specifically
discussed in this decision, its application is evident. Whereas the
specification promises that the claimed pregabalin or its racemate is effective
in treating a broad range of pain, in fact pregabalin is only useful in
treating chronic or persistent pain, and there was no evidence that its
racemate is useful whatsoever in treating pain. Justice Hughes’ comment that
his “decision may well have been different had the claims at issue been
directed only to pregabalin and only to certain specific types of pain”,
highlights the importance of drafting the specification to accurately reflect
the promise made under the terms of the patent bargain.