Its Alive! Court of Appeal resurrects clopidogrel enantiomer patent



On July 24, 2013, the Federal Court of Appeal released its Reasons for Judgment in an appeal involving Canadian Patent No. 1, 336, 777 and Sanofi’s clopidogel product, PLAVIX. In 2011, Justice Boivin (2011 FC 1486) had concluded that the 777 Patent was invalid for failing to meet the promise of the patent, specifically, that clopidogrel was useful in humans. Justice Boivin has also held that the 777 Patent was obvious to try in light of prior art disclosing racemic clopidogrel and a general motivation to separate enantiomers.

The 777 Patent, which was considered by the Supreme Court of Canada in the context of a proceeding under the Patented Medicines (Notice of Compliance) Regulations, is a selection patent wherein the dextrorotary enantiomer was selected from the previously disclosed racemic mixture disclosed in, among other places, Canadian Patent No. 1,194,875.

Utility – Promise of the 777 Patent

Justice Pelletier, with whom Justice Noël concurred, concluded that the Trial Judge had erred in importing a promise of therapeutic utility in humans. Justice Pelletier, clarified that the earlier decision of the Court of Appeal in olanzapine did not mean that all patents contain an explicit promise:

[50] When this Court said at paragraph 80 of Olanzapine, cited above, that the promise of the patent must be ascertained, it should not be taken to have assumed that every patent contains an explicit promise of a specific result since, subject to what is said below with respect to selection patents, there is no obligation on the part of the inventor to disclose the utility of his invention in the patent. In Olanzapine, the Court was simply indicating that the firs step in assessing utility was to determine the standard against which utility will be measured. This requires the Court to construe the patent to determine if a person skilled in the art would understand it to contain an explicit promise that the invention will achieve a specific result. If so, the inventor will be held to that promise. If there is no explicit promise of a specific result, then a mere scintilla of utility will do.

Justice Pelletier concluded that the Trial Judge had erred by reading in the promise of therapeutic utility in humans based on “indications” or “inferences” in the disclosure:

[66] While these “indications” are consistent with human use, they are not inconsistent with other uses. Although Dr. Hirsh was entitled to form an opinion on the basis of the inference which he drew, the Trial Judge was held to a higher standard. He erred in law in reading into the ‘777 patent a promise for use in humans on the basis of inferences, in the absence of language at least as clear and unambiguous as that used to establish the advantages of the selection over the compouds of the genus patent.

Since the trial judge had found that the inventors had demonstrated that clopidogrel had greater therapeutic effect and less toxicity than the compounds of the 875 Patent, Justice Pelletier concluded that Apotex’s attack based  on inutility ought to have been dismissed.


Justice Pelletier concluded that the key factor in the Supreme Court of Canada’s “obvious to try” analysis was the lack of knowledge of the properties of the enantiomers of the compounds of the 875 Patent. Justice Pelletier held that the Trial Judge found himself in the exact same position as the Supreme Court of Canada and ought to have come to the same conclusion, namely that the invention of the 777 Patent was not the difficulty in separating the enantiomers but rather the unknown properties of the enantiomers once resolved. Without any knowledge of the advantageous properties, Justice Pelletier concluded that the skilled person would not think to separate the enantiomers of the clopidogrel racemate and the absence of this knowledge was fatal to Apotex’  “obvious to try” attack:

[81] Given that the Trial Judge applied the test for obviousness set out in Plavix, and given that he applied it to the same material facts as the Supreme Court, he ought to have come to the same conclusion. His error lay in failing to recognize that the unknown nature of the properties of the enantiomers of PCR 4099, or of any of the other compounds of the ‘875 Patent, was fatal to the “obvious to try” analysis. Put another way, the distance between the common general knowledge and the inventive concept of the ‘777 Patent could not be bridged by routine experimentation since the results to be obtained were unknown. On the facts, this was confirmed by the fact that the inventors, who had more knowledge that the person of ordinary skill in the art, attempted to resolve a number of other compounds before finally trying PCR 4099: see Reasons, at paragraphs 752-759.


Justice Pelletier held that Trial Judge was correct to conclude that Apotex’s limitation defences were not applicable, albeit for perhaps the wrong reasons. The Trial Judge was correct to deny Apotex the exception to infringement provided by section 55.2 of the Patent Act because Apotex could not account for the ultimate use of clopidogrel tablets used for regulatory purposes.  In such circumstances, it was reasonable to infer that they were subsequently sold, a use which fell outside the exception provided by subsection 55.2(1)

Justice Pelletier also concluded that the importation of clopidogrel into Canada from Mexico was not a cause of action that arose in Ontario alone such that a six year limitation period applied and that none of Sanofi’s claims were time barred.

Justice Pelletier further held that Apotex could not rely on an agreement Apotex had entered into in the United States limiting Apotex’ damages to 50% of U.S. sales, because Apotex’ repudiated that agreement when it sought to impeach the 777 Patent:

[117] It is inconceivable that Apotex could retain immunity from the consequences of its infringement of the ‘777 Patent while at the same time seeking a declaration of invalidity of that patent. If terms are to be implied into the Liability Exposure Provision to give it business efficacy, surely one of the implied terms would be that the parties would accept the decision of the U.S. court as binding on them for the purposes of their dealings in Canada. Apotex would retain 50% of its net U.S. sales even though it infringed the ‘265 patent but in return Apotex would respect Sanofi’s Canadian monopoly. In commencing an action seeking a declaration of invalidity of the ‘777 Patent, Apotex breached the implied term and lost the benefit which it would otherwise have enjoyed under the Liability Exposure Provision.

Justice Gauthier’s Concurring Reasons

Justice Gauthier also noted that not every patent contains a promise of utility and that the Court ought to be particularly prudent in applying Consolboard to statements in the disclosure clearly based on expectations. Where the advantages required to make the selection inventive were not based in speculation but were fully and properly described and demonstrated, the level of disclosure required by law should be lower:

[133] It is clear that the Trial Judge was satisfied that the patent application was not filed on the basis of mere speculation. The patentee had a solid track record based on an extensive research program and a reasonably sound line of reasoning. It is not challenged here that the invention is indeed useful and extensively used. Thus, neither the description of the invention (per s. 34 of the Act) nor the policy reasons discussed in the AZT decision at paragraph 69 are at issue.

[134] In contradistinction with the situation in AZT, where the invention claimed was the new use/utility and thus the quid pro quo for the grant of the monopoly was a full disclosure in respect of such utility, the public here received all the information necessary to make and use clopidogrel, the invention claimed in the ‘777 Patent. The Trial Judge found, and this is no longer challenged, that the advantages necessary to make the selection inventive and thus justify the grant of a monopoly on clopidogrel were fully and properly described and demonstrated in the patent.

[135] In such a case, the level of disclosure required by law should be lower. If again I were to assume that the Trial Judge’s construction was correct, the clear indication in the statement at page 21 of the ‘777 Patent that use in humans was predicted as opposed to demonstrated should be sufficient at law to meet the test for sound prediction. Indeed, this is enough to enable the public to know that such practical application was not demonstrated at the time the patent application was filed. Therefore, the public would have the ability to challenge the monopoly based on whether it was granted on mere speculation, and determine whether the inventor in fact had the required factual basis and sound line of reasoning to support this statement at the relevant time.

On obviousness, Justice Gauthier held that the Trial Judge had erred by failing to weigh the extent, nature and amount of work required to arrive at a decision to actually develop PCT 4099 as apposed to any of the 21 other exemplary compounds of the 875 Patent. Relying the inventors actual course of conduct, Justice Gauthier concluded that the 875 Patent would not point directly or indirectly to the clopidogrel racemate and that the Trial Judge’s conclusion on obviousness could not stand.

A copy of the Court of Appeal’s Reasons for Judgment may be found here.