FC Finds Teva’s Allegation Justified that the SEROQUEL Patent is Obvious

FC Finds Teva’s Allegation Justified that the SEROQUEL Patent is Obvious

AstraZeneca Canada Inc. v. Teva Canada Limited, 2013 FC
245

AstraZeneca seeks an order prohibiting the
Minister of Health from issuing a Notice of Compliance to Teva Canada in
respect of quietiapine fumarate extended release tablets (sold under SEROQUEL
XR) until the expiry of Canadian Patent No. 2,251,944 (‘944). By the time of
the hearing, the only grounds of the NOA advanced were invalidity based on
obviousness and ambiguity.

Application is dismissed. The allegation of
invalidity is justified on ground of obviousness.

Claim Construction

Claim 1: A sustained release
formulation comprising a gelling agent and
11-[4-[2-(2-hydroxyethoxy)ethyl]-1-piperazinyl]dibenzo-[b,f][1,4]thiazepine or
a pharmaceutically acceptable salt thereof, together with one or more
pharmaceutically acceptable excipients.

Where, as in this case, the inventive concept
of the claims is not discernible from the claims themselves because they
present a bare chemical formula, the Court is directed to read the
specification in the patent to determine the inventive concept of the claims.

A purposive and complete reading of the patent
leads the Court to conclude that a decreased occurrence of dose dumping and a
less frequent dosing regimen are key elements of the inventive concept claimed
by the ‘944 patent.

Obviousness

The Court held that the claimed invention was
obvious based on the four-step obviousness framework outlined by the Supreme
Court in Sanofi.

At the fourth step, the Court applied the
obvious-to-try analysis, and held that the question in this analysis is whether
it is more or less self-evidence to try to obtain the invention. The Court
rejected AstraZeneca’s position that the analysis requires asking whether it is
obvious, before any experimentation is carried out, that successful results
will be achieved.

Then the Court assessed four factors relevant
to the obvious-to-try analysis. First, the Court interpreted “self-evident”,
and held that the correct standard against which to assess obviousness is not
“predict with certainty,” but rather “fair expectation of success.” Upon
analyzing the evidence, the Court concluded that it was self-evident or plain
that there was a fair expectation that a sustained release formulation of
quetiapine using HPMC would be successful.

Second, the Court assessed the extent, nature
and effort required to achieve the invention. The Court found that the choice
of HPMC and its specific grades would have been the product of routine
experimentation.

Third, the Court assessed whether the skilled
person would have been motivated to achieve the invention. The Court first
clarified the definition of the skilled person, and held that while it is true
that the clinician and the formulator are both part of the “team” that
comprises the notional person skilled in the art in this case, it is a notional
skilled person upon whom the characteristics of the real-life team are layered,
and not a notional skilled team.  As such, both clinician and formulator
are equal participants in each step of the “obvious to try” test. Then the
Court held that the skilled person would not have viewed the hurdles to
achieving the invention as “lions in the path”, but rather as paper tigers.

Fourth, the Court assessed the inventors’
actual course of conduct in arriving at the invention. The Court noted that
AstraZeneca did not lead any evidence with respect to the length or difficulty
of the trials conducted, or with respect to whether their inventors possessed a
knowledge base that was above that which should be attributed to the skilled
person in this case. The Court drew and adverse inference from this lack of
evidence.

Overall, the Court held that it was more or
less self-evident to try to obtain a sustained release formulation of
quetiapine using HPMC, and that the person skilled in the art would have had a
fair expectation of success.

Ambiguity

Considering its finding of obviousness, the
Court declined to address the ambiguity argument.