Patentees Score A Victory In The Supreme Court Of Canada: Validity Of Selection Patents Upheld

Overview

On Thursday, November 6, 2008, the Supreme Court of Canada

released its much-anticipated decision in Sanofi-Synthelabo

Canada Inc. v. Apotex Inc., 2008 SCC 61

(Sanofi). In this landmark decision, the Supreme Court

gives considerable strength to pharmaceutical patents by rejecting

Apotex's generalized attack on selection patents as

"evergreening" and holding that selection patents do not

differ in nature from any other type of patent. The case is also

significant because it adds important clarification to the test for

anticipation and brings the law with respect to obviousness into

closer alignment with that of the United States and United

Kingdom.

Background

The Sanofi case commenced as an application to the

Federal Court of Canada brought pursuant to the Patented

Medicines (Notice of Compliance) Regulations, in respect of

the blockbuster drug PLAVIX (clopidogrel bisulfate). Sanofi is the

holder of Canadian Patent No. 1,194,875. The '875 Patent

contains "genus" claims that encompass about 250,000

compounds, including the racemate of clopidogrel. A racemate is a

substance containing equal amounts of two structurally different

compounds called optical isomers. Although isomers share the same

molecular formula, they can have very different properties.

Significantly, the '875 Patent does not distinguish between the

isomeric forms of clopidogrel — both are encompassed

within the claims.

Sanofi subsequently discovered that a particular isomer of

clopidogrel is less toxic and better tolerated than its other

isomer. It is the beneficial isomer that was claimed in Canadian

Patent No. 1,336,777.

Apotex challenged the validity of the '777 Patent on the

grounds of anticipation, obviousness, and double patenting. Sanofi

was successful at trial and on appeal. The Supreme Court also found

in favour of Sanofi and dismissed Apotex's appeal. As a result,

the Minister of Health is prohibited from issuing regulatory

approval to Apotex in respect of its clopidogrel product prior to

the expiry of the '777 Patent.

The Decision

The Sanofi decision involves a so-called "old

Act" patent. While the statutory law cited by the Court

therefore comes from the Patent Act as it read pre-October

1989, the decision will undoubtedly have broad applicability even

to so-called "new Act" patents.

Anticipation

Justice Rothstein (writing for the Court) relies heavily upon

the House of Lords' decision in Synthon BV v.

Smithkline Beecham plc, [2005] UKHL 59, which articulates

the two-step approach to the anticipation inquiry: "prior

disclosure" and "enablement." This approach, which

had already been applied in some cases in the lower courts, is now

solidified in Canadian law.

For a claim of a selection patent to be anticipated, the first

requirement is that the prior patent must disclose subject matter

that, if performed, would necessarily

result in the infringement of the subsequent patent. There is no

room for trial and error or experimentation by the skilled person.

If no such disclosure is apparent from reading the document, there

is no anticipation. In the case of the '875 Patent, since it

did not disclose the special advantages of the isomer claimed in

the '777 Patent, the disclosure requirement was not met. It was

not sufficient that the compound claimed in the selection patent

was also encompassed within a...