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Newsflash | Selection Patents
November 7, 2008 - Selection Patents:
Alive and Well in Canada
The Supreme
Court of Canada released its long awaited decision in
Apotex Inc. v. Sanofi‑Synthelabo Canada Inc., 2008 SCC 61
that will transform and harmonize Canadian patent law with
decisions in the United Kingdom and United States.
This case required the Court to
determine whether selection patents are invalid in principle
or on the facts of this case on the grounds of
anticipation, obviousness and double patenting
Background
Generally, a selection patent is a subsequently filed patent
based on a selection of compounds from those described in
general terms and claimed in an originating patent. A
selection patent claims a substantial advantage to be secured
or disadvantage to be avoided by the use of the selected
members in respect of a quality of a special character
peculiar to the selected group.
Sanofi was the holder of the ‘875 patent which
discloses a large genus or class of over 250,000 possible
compounds useful in inhibiting platelet aggregation activity
in the blood. Sanofi also held the subsequent ‘777 patent
which disclosed and claimed clopidogrel bisulphate, which was
marketed under the trade name of Plavix as an anti‑coagulant
that exhibits platelet aggregation inhibiting activity.
Apotex sought to market its generic
version of Plavix, claiming that it would not infringe
Sanofi's patent for Plavix because the ‘777 patent was invalid
on the grounds of anticipation, obviousness and double
patenting.
Anticipation
The Court held that under Canadian law a system of genus and
selection patents is acceptable in principle and does not
necessarily involve anticipation and therefore invalidity.
Previously, anticipation was based on a determining whether
the invention in a patent had been disclosed in a single prior
publication or patent. The Court relaxed this requirement and
adopted the approach set out in the UK decision in Synthon
B.V. v. SmithKline Beecham plc, [2006] 1 All E.R. 685,
[2005] UKHL 59. Under this approach,
a two‑step approach should
be adopted whereby the requirements of“prior
disclosure”and“enablement”should be considered separately and
proven. For prior disclosure, the genus patent must disclose
subject matter which, if performed, would necessarily result
in infringement of that patent. At this stage, the person
skilled in the art is reading the prior patent to understand
whether it discloses the special advantages of the second
invention. No trial and error is permitted. If in reading the
genus patent, there is no discovery of the special advantages
of the selection patent, the genus patent does not anticipate
the selection patent and the disclosure requirement to prove
anticipation, as in this case, fails.
For "enablement", the person
skilled in the art must have been able to perform the
invention without undue burden. The question at this stage of
the test is how much trial and error or experimentation is
permitted. If an inventive step were required to get to the
invention of the second patent, the specification of the first
patent would not have provided enabling disclosure. The
entire prior genus patent must provide enough information to
allow a person skilled in the art to perform or make the
selected subsequently claimed invention without“undue
burden". The skilled person may use his or her common general
knowledge of the relevant art at the relevant time to
supplement information contained in the prior genus patent and
may conduct routine trials without being considered an undue
burden, but prolonged or arduous trial and error experiments
would not be considered routine.
Obviousness
With respect to obviousness, the Court also relaxed the rigid
test for obviousness which required a determination of whether
a technician skilled in the art
but having no scintilla of inventiveness or imagination; a
paragon of deduction and dexterity, wholly devoid of
intuition; a triumph of the left hemisphere over the right,
would, in the light of the state of the art and of common
general knowledge as at the claimed date of invention, have
come directly and without difficulty to the solution taught by
the patent. This previous test did not
accommodate a “worth a try” test by the skilled person.
The Court considered the tests set out by the
UK and US courts in Generics (UK) Ltd. v. H. Lundbeck
A/S, [2008] R.P.C. 19, and KSR International Co. v.
Teleflex Inc., 127 S. Ct. 1727 (2007), respectively, and
concluded that an “obvious to try” test can be relevant in an
obviousness inquiry. The Court adopted and re-stated the new
approach to be followed from the decision in
Windsurfing International Inc. v. Tabur
Marine (Great Britain) Ltd.,
[1985] R.P.C. 59 (C.A.), and Pozzoli SPA v. BDMO SA,
[2007] F.S.R. 37, [2007] EWCA Civ 588,
as follows:
(1)
(a) Identify the notional
“person skilled in the art”;
(b) Identify
the relevant common general knowledge of that person;
(2)
Identify the inventive concept of the claim in question or if
that cannot readily be done, construe it;
(3) Identify what, if
any, differences exist between the matter cited as forming
part of the“state of the art”and the inventive concept
of the claim or the claim as construed;
(4) Viewed without any knowledge of
the alleged invention as claimed, do those differences
constitute steps which would have been obvious to the person
skilled in the art or do they require any degree of invention?
The issue of “obvious to
try” will arise at the fourth step of the inquiry. For a
finding that an invention was “obvious to try”, there must be
evidence to convince a judge on a balance of probabilities
that it was more or less self‑evident to try to obtain the
invention. Mere possibility that something might turn up is
not enough.
In the case at bar, the
Court concluded that the selection patent was not anticipated
because there was no evidence
that a person skilled in the art would know, from reading the
original patent, the specific beneficial properties associated
with the more active dextro‑rotatory isomer and that it would
be less toxic than the racemate or levo‑rotatory isomer or any
of the other compounds made and tested. Further, the
selection patent was not obvious since there there were five
well‑known methods to separate this racemate into its isomers,
there was no evidence that a person skilled in the art would
have known which of the five known separation techniques would
work with this racemate. Moreover, Sanofi had spent millions
of dollars and several years developing the racemate up to the
point of preliminary human clinic trials before it was
discovered that the dextro‑rotatory isomer was active and
non‑toxic.
Double Patenting
Finally, the challenge to selection patents based on the
ground of double patenting was also rejected. The Court
stated that strategies that attempt to extend the time limit
of exclusivity of a patent may be contrary to the objectives
of the Patent Act, depending on the circumstances, but
a generalized concern about evergreening is not a
justification for an attack on the doctrine of selection
patents. Further, selection patents encourage improvements
over the subject matter of the original genus patent because
that selection does something better than or different from
what was claimed in the genus patent.
Conclusions
The comments by the Court reflect a significant change in
Canadian patent law from a rigid to a more flexible approach
that reflects developments in the UK and the USA. First,
while the Court has relaxed the criteria for assessing
anticipation and obviousness, it has confirmed that a system
of genus and selection patents is acceptable. Second, the
Court has also confirmed that evergreening and strategies that
attempt to extend the time limit of exclusivity of a patent is
permissible and proper so long as anticipation and obviousness
issues are addressed. The Court acknowledged and accepted
that selection patents encourage improvements over the subject
matter of the original genus patent because that selection
does something better than or different from what was claimed
in the genus patent. In this regard, the degree of time and
investment expended by a patentee to demonstrate an advantage
of particular compounds over the compounds claimed in the
genus patent are likely to lead to an inference that the prior
art and common general knowledge of persons skilled in the art
was not sufficient to render the selection patent obvious.
This conclusion will favour patentees who are concerned about
their ability to obtain patent protection of the results
following significant expenditure of time and investment.
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