This was an application brought by AstraZeneca under the
provisions of the Patented Medicines (Notice of Compliance)
Regulations for an order prohibiting the Minister of Health
from issuing a notice of compliance to Apotex for 20 and 40 mg
esomeprazole magnesium tablets until after the expiry of Canadian
Patent No. 2,139,653 (the '653 patent). If successful on the
application, this would have prevented Apotex from marketing a
generic version of NEXIUM in Canada for treating conditions wherein
a reduction of gastric acid secretion is required until May 27,
2014. Apotex, on the other hand, sought early market entry by
arguing that the '653 patent was invalid for lack of sound
prediction, anticipation (or lack of novelty), and obviousness.
The '653 patent relates to an improved process for preparing
highly optically pure esomeprazole, one of the enantiomers of the
racemate omeprazole, that is stable against racemisation (i.e.
recombination). Claim 8 was the claim at issue and could be read as
claiming a salt (e.g. magnesium) of esomeprazole having an optical
purity of 99.8% or greater. There was no provision as to utility
(or use of the invention) in claim 8. This was an important fact,
as the Court noted that where the invention relates to a new
compound, utility does not need to be included in the claim, so
long as it is described in the description portion of the patent.
On the other hand, when the patent relates to a new use for an old,
known compound, that new use must be set out in the claims. In this
case, claim 8 was not directed to a new compound; it was directed
to a previously known compound having a particular purity.
Moreover, utility of the compound was simply described in the
description of the patent as follows:
It is desirable to obtain compounds with improved
pharmacokinetic and metabolic properties which will give an
improved therapeutic profile such as a lower degree of
interindividual variation. The present invention provides such
compounds, which are novel salts of single enantiomers of
However, nowhere in the patent, whether in the Examples or
otherwise, was any information given to the person skilled in the
art as to whether, in fact, the highly pure esomeprazole salt does
give an improved therapeutic profile such as a lower degree of
interindividual variation. Moreover, there was no evidence from any
witness to say that there was anything in the disclosure of the
'653 patent that would inform a person skilled in the art that
the purified esomeprazole salt would fulfill this promise. As a
result, there was a clear question as to whether the invention had
a basis for a "sound prediction" as to utility.
The requirements for sound prediction are well established: 1)
there must be a factual basis for the prediction; 2) the inventors
must have as of the date of the patent application an articulable
and sound line of reasoning from which the desired result can be
inferred from the factual basis; and 3) there must be proper
The facts of the present case did not show that as of the
priority date, May 1993, or even the Canadian filing date, May
1994, that the inventors had either a factual basis for a
prediction that an esomeprazole salt of a particular purity would
have the utility indicated in the patent, nor did they have an
articulable and sound line of reasoning for inferring such a
result. In addition, clearly there was no proper disclosure in the
patent in that respect. As a result, the patent was invalid for a
lack of sound prediction.
As to anticipation, the question was, given that prior art
German patent application DE 40 35 455 A1 (DE '455) described a
process for separating the enantiomers of omeprazole (and salts)
into "optically pure" fractions, did the description,
particularly Examples 5 and 6 (incorporating Examples 1 and 2)
"enable" what was claimed in claim 8 of the '653
patent, a purity of 99.8% (ee) or greater? In this respect, the
Court found that to practice DE '455 "would at best only
occasionally result in a product with the purity level stipulated
in claim 8." On this basis, there was no enablement such as
would support an allegation of anticipation.
As to obviousness, the Court was satisfied on the evidence that,
as of the claim date, May 1993, it was known that omeprazole could
be separated into its enantiomers (+) and (-), that they would be
useful, just as omeprazole was, in treating gastric problems, and
that they could be processed in salt form with a salt such as
magnesium. A purity of 95.6% (ee) for esomeprazole had been
reported as having been achieved in the prior art, and such
technique could have been used to increase that purity to 99.8%
(ee) if desired. In the result, the '653 patent was also found
to be invalid for obviousness.
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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.
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