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Federal Court Invalidates Sanofi’s Plavix Patent for Alleged Insufficiency and Obviousness

January 11, 2012

On December 6, 2011, the Federal Court of Canada issued its decision1 in the well-known dispute between Apotex Inc. and Sanofi-Aventis over the anticoagulant drug, clopidogrel bisulfate, sold in Canada under the brand name Plavix. This compound is a single enantiomer of a previously disclosed racemate. The Court invalidated Sanofi’s patent (Canadian patent no. 1,366,777, “the ′777 Patent”). An appeal has been filed by Sanofi.

This decision followed a trial in which Sanofi had sued Apotex in an infringement action and Apotex counterclaimed that the patent was invalid.  The Plavix dispute has previously been the subject of separate litigation via a Patented Medicines Notice of Compliance (NOC) Proceeding, which eventually ended up in front of the Supreme Court of Canada.2 In the NOC cases, Sanofi prevailed and their patent was held to be valid in an important precedent where the Supreme Court reviewed and modified the legal tests for obviousness and anticipation. The NOC Proceeding is a summary application process and does not preclude the parties from later initiating an action for infringement or validity.

Justice Boivin, who wrote the trial decision for the Federal Court of Canada, addressed the difference in outcomes between his court and the SCC by noting that the evidentiary records were different. In the present proceedings, oral testimony (not permitted in NOC proceedings) was heard from 9 experts and 14 fact witnesses on a broader range of issues, including a consideration of sound prediction – which was not addressed in the NOC proceedings.  Accordingly, Justice Boivin concluded that the NOC proceedings are not fact determinative, and are “not the gospel.”3

The central issue in the determination of validity of the ′777 Patent in the present case was sound prediction. To assess whether or not the invention claimed in the ′777 Patent was soundly predicted, the court reiterated a message that has echoed through several recent cases, that is: “The promise of the patent must be ascertained.”4

Not surprisingly, the opposing parties had vastly differing opinions on the construction of the patent with respect to its promise. Apotex argued that the promise of the ′777 Patent relates to use in humans whereas Sanofi argued that it merely relates to a “potential use” in humans. Importantly Justice Boivin concluded that the proper purposive construction of the ′777 Patent is that it promises a use of the invention in humans. In particular, the following words used in the ′777 Patent were critical in Justice Boivin’s finding: “medicine”, “patient”, “pharmaceutical compositions”, “Active pharmaceutical index” and “medicine of the invention.”  Also determinative was the fact that the ′777 Patent is a selection patent of Canadian Patent No. 1,194,875, which specifically mentions applications of compounds in humans. Since a selection patent, in most cases, should not promise less than the genus patent, Justice Boivin argued that this is another reason that the promise of the ′777 Patent is use in humans.

A very detailed analysis of the three requirements for sound prediction5 was conducted and, recalling that the promise of the patent was for use in humans, Justice Boivin held that the ′777 Patent did not sufficiently disclose the factual basis and sound line of reasoning for the person skilled in the art to predict that the invention fulfilled its promise. During trial an exhaustive “track record” on the part of Sanofi in the study of this class of compounds and their pharmacology and toxicology was established, however, since critical parts of this record were not in the ′777 Patent, the patent was held invalid for insufficient disclosure.

While Justice Boivin did not need to address other reasons for invalidity of the ′777 Patent, he went on to analyze the issue of obviousness and, contrary to the SCC decision, held that this patent was also invalid because it was obvious. One consideration that led to this finding (and the contradiction with the Supreme Court) was the testimony of one of the inventors in support of undue experimentation to obtain the compound (a single enantiomer of a known racemic compound). The inventor’s testimony was found to be inconsistent and, as a result, not reliable.  Since the racemic compound was part of the common general knowledge, a person skilled in the art, in the mid-1980’s, would have been directed to the classic method used to separate the enantiomers and it was established that there was motivation to perform the separation, the invention was held to be obvious to try.

As we recently advised in our report on the continuing Olanzapine saga, when it comes to selection patents, in particular in the pharmaceutical arts, it is important to ensure that the patent provides sufficient support of their promised utility. In general, Applicants should include any supporting data that they have on hand to ensure that they meet the requirements of a sufficient disclosure for sound prediction. One may also want to consider the language used in an application to describe a promised utility, ensuring that the patent is not restricted to a higher promised utility than what might be supported.


1Apotex Inc. v. Sanofi-Aventis, 2011 FC 1486.  
2Sanofi-Synthelabo Canada Inc. v. Apotex Inc. FC 390, 39 CPR (4th) 202; Sanofi-Synthelabo Canada Inc. v. Apotex Inc, 2006, FCA 421, 59 CPR (4th) 46; Apotex Inc. v Sanofi-Synthelabo Canada Inc. v. Apotex Inc. 2008 SCC 61, 69CPR (4th) 251.  
3Apotex Inc. v. Sanofi Aventis, ibid [28].  
4Ibid [141]-[143].  
5The SCC in Apotex Inc. v Wellcome Foundation Ltd., 2002 SCC 77, [2002] 4 SCR 153 held that in order to have a sound prediction there must be (1) factual basis, (2) sound line of reasoning and (3) proper disclosure.

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Author(s):

Patricia Folkins Patricia Folkins
B.Sc. (Honours Chem.), Ph.D. (Org. Chem.)
Partner
905.817.6101  email Patricia Folkins