Apotex cannot stop sticky platelets without a patent

On Thursday November 6, 2008 the Supreme Court of Canada (“SCC”) released its decision in Apotex Inc v Sanofi-Synthelabo Canada Inc, [2008] 3 SCR 265. This intellectual property case involves a dispute over selection patents between Apotex Inc. (“Apotex”), a generic drug manufacturer, and Sanofi-Synthelabo Canada Inc (“Sanofi”) who held the original patent. TheCourt published a summary of the Federal Court of Appeal case when leave to the SCC was granted more than one year ago.

Sanofi held the original ‘875 patent which covers nearly a quarter-million compounds which can inhibit platelet aggregation activity, or clotting, in the blood. This case involved one of these compounds known as a racemate, a substance which contains equal amounts of two structurally different compounds called the dextro‑rotatory isomer and the levo‑rotatory isomer. The ‘875 patent holder, Sanofi, also held a subsequent ‘777 selection patent which was the dextro‑rotatory isomer. The drug is marketed under the trade name Plavix as an anti-coagulant which essentially inhibits the blood from clotting. Apparently the isomer that was used to make Plavix is less toxic and better tolerated than its counterpart the levo‑rotatory isomer.

But what does Plavix do? On this US website the manufacturer of PLAVIX claims clots in the blood cause more than 90% of heart attacks and more than 85% of strokes. The manufacturer further claims this drug is “proven to help keep platelets from sticking together and forming clots, which can help protect against a future heart attack or stroke.”

Apotex sought a Notice of Compliance (“NOC”) from the Minister of Health which would allow them to produce a generic version of Plavix. The judgment described the NOC process as follows:

A manufacturer, usually a generic manufacturer, wishes to compare its drug with that of a patent holder for which a patent list has been submitted to the Minister by the patent holder. The generic manufacturer’s purpose is to establish the safety and efficacy of its drug for the purposes of securing marketing approval from the Minister. The process of comparison saves the generic competitor time and resources.

However, the Minister will not issue a Notice of Compliance unless the patent on the comparator drug has expired, is invalid, or the generic’s product will not otherwise infringe the patent. Thus the NOC Regulations create a connection between government approval to market a generic drug and the issue of patent validity and infringement.

Apotex’s position was that some claims from the ‘777 patent for Plavix were invalid because they were anticipated by the ‘875 patent. Apotex further accused the drug manufacturer of obviousness and double patenting in the ‘777 patent. Thus Apotex requested the Minister of Health issue an NOC for Plavix since it was not protected by a valid patent.

Perhaps unsurprisingly, Sanofi opposed this application in Federal Court. Sanofi obtained an order from the Federal Court of Appeal prohibiting the Minister of Health from issuing a Notice of Compliance on grounds the ‘777 patent was invalid. Apotex appealed this decision to the SCC.

The issue of selection patents

Originating patents like ‘875 involve an originating invention. In the field of chemical patents, this usually involves the discovery of a new reaction or compound. Selection patents are based on a selection of compounds described in general terms in an originating patent. A selection patent must be made after the originating patent to be novel and furthermore requires a special property of an unexpected character. Otherwise, a selection patent does not differ from any other patent.

Apotex argued the selection ‘777 patent was invalid in principle and specifically on the grounds of anticipation, obviousness and double patenting.


The SCC affirmed a two step approach for anticipation and rejected the appellant’s arguments that selection patents are invalid in principle. The first step involves disclosure of the selection patent in the originating patent. The ‘875 patent was not found to disclose the special advantages of the ‘777 patent, such as reduced toxicity. Therefore the benefits of the ‘777 patent could not have been anticipated by the originating ‘875 patent.

Enablement is the second step of the anticipation analysis. A skilled reader should be able to arrive at the invention the first time they try it and each time after, with limited trial and error. Since anticipation requires both disclosure and enablement, it was unnecessary for the SCC to conclude if there was enablement after finding there was no disclosure. Therefore, the ‘875 patent was found to not anticipate the ‘777 patent as alleged by Apotex.


Courts have supplemented the definition of “invention” contained in statute with the notion of “obviousness.” Professor David Vaver explains “Inventions implied inventive ingenuity, without which an advance was obvious; and patents are not granted for the obvious.

The test for obviousness cited by the SCC involves a four steps: (1) Identifying the person “skilled in the art;” (2) Identifying the inventive concept; (3) Identifying differences between the “state of the art” (‘875) and the inventive concept of the claim (‘777); and (4) Viewed without knowledge of the alleged invention, would the differences be “obvious to try” for a skilled person or do they require a degree of invention?

The SCC found that the appellant failed to establish that the ‘777 patent for the dextro-rotatory isomer would have been “obvious to try” from the ‘875 patent. If it were, Sanofi would not likely have spent the time and resources to develop the Plavix. To satisfy the “obvious to try” test the invention should be more or less self-evident to someone skilled in the art.

Double Patenting

Apotex challenged the doctrine of selection patents on the basis that there may only be one patent covering an invention. They argued granting selection patents allows for “evergreening” or extending the lifetime of an original patent by registering selection patents in the future. The SCC rejected this argument, pointing out that selection patents may be obtained by third parties and that such patents encourage improvement by selection.

The original ‘875 patent was granted under the doctrine of sound prediction. This doctrine “balances the public interest in early disclosure of new and useful inventions even before their utility has been fully verified by tests, and the public interest in avoiding cluttering the public domain with useless patents and granting monopoly rights in exchange for misinformation.” Since the original patent involved over 250,000 compounds it was not possible for the respondent to test them all.

The SCC upheld the applications judge’s finding that the claims of the ‘777 and ‘875 patents were not the same, and that they were furthermore not based on the same compounds. Therefore, there was no double patenting found for these inventions.


The SCC found that the ‘777 patent neither anticipated nor was obvious from the ‘875 patent, and rejected Apotex’s allegations of double patenting. It therefore appears that the doctrine of selection patents will live to see another drug.

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