On December 6, 2011, Justice Boivin of the Federal Court held that Apotex infringed the patent that claims clopidrogel bisulfate (sanofi-aventis's PLAVIX) but that the patent was invalid: Apotex Inc. v. sanofi-aventis 2011 FC 1486, appeal pending.
The same patent (’777) had previously been the subject of litigation under the Patented Medicines (Notice of Compliance) Regulations. As reported in the November 2008 special edition of Rx IP Update, the Supreme Court of Canada upheld the Order of prohibition preventing the Minister of Health from issuing a Notice of Compliance ("NOC") to Apotex (2008 SCC 61). Following its loss in the Supreme Court, Apotex brought an impeachment action, and sanofi-aventis followed with an infringement action. The December 6 decision relates to both actions.
The ’777 patent discloses and claims the enantiomer clopidogrel and its bisulfate salt, as well as processes for its manufacture. An earlier patent (’875) encompassed clopidogrel bisulfate within its claims and included an example describing the racemate. The claims also referred to enantiomers.
Starting with the position that the ’777 patent is a selection patent, the Federal Court concluded that the invention of the ’777 patent is a compound that is useful in inhibiting platelet aggregation, has greater therapeutic effect and less toxicity than the other compounds of the ’875 genus patent, including the racemate and the opposite enantiomer, has the advantages of the salts (crystallize easily, not hygroscopic and sufficiently water-soluble) and the methods for obtaining that compound. Further, the Federal Court held that the patent made an explicit promise for the use of the compound in humans.
Invalidity
The Federal Court rejected Apotex's assertions that the ’777 patent was invalid for overbreadth, insufficiency, lack of novelty and double-patenting. The Federal Court's decision is consistent with the Supreme Court's ruling on the latter two grounds.
The Federal Court found the patent invalid on the basis of lack of utility, both demonstrated or soundly predicted, and obviousness.
Demonstrated utility
Sanofi-aventis had argued that the promised utility had been demonstrated as of the Canadian filing date, at which time a phase 1 clinical study of the compound was underway. While some of the results of the double-blind study were known to sanofi-aventis at the date of filing, the study was not completed until one month later. The Federal Court held that the early results known by sanofi-aventis were inconclusive on the issue of the promised utility.
Sound prediction
With regards to sound prediction, the Federal Court found that sanofi-aventis had a "track record" studying compounds with similar structures to clopidogrel bisulfate. As a result of this "track record," sanofi-aventis established that it had a factual basis and sound line of reasoning for predicting that clopidogrel bisulfate could be used in humans. However, the Court found that the patent did not disclose this "track record," which the Court held was needed to assist the skilled person to predict the promised use. As a result, the patent failed the disclosure branch of the sound prediction test.
Obviousness
In contrast to the Supreme Court's finding that Apotex's allegation of obviousness was not justified in that proceeding, the Federal Court held the invention of the ’777 patent "obvious to try." The Federal Court reasoned that the racemate of clopidogrel was part of the common general knowledge of the skilled person, that the skilled person would have been motivated to resolve the enantiomers of a racemate, and that a particular method of resolving the enantiomers would have been routine at the time.
Infringement
While in principle moot because of the finding of invalidity, the Federal Court nonetheless addressed sanofi-aventis's claim of infringement. The Federal Court held that Apotex infringed the ’777 patent by, among other acts, importing clopidogrel bisulfate and exporting Apo-clopidogrel tablets to the United States.
In the U.S., the parties had entered into settlement agreements regarding the U.S. litigation relating to the U.S. patent claiming clopidogrel bisulfate. By the agreements, Apotex's liability for infringement in the U.S. was limited to 50% of its net sales. Apotex had argued that sanofi-aventis was precluded from recovering for the U.S. Apo-clopidogrel on the basis of these settlement agreements. The Federal Court disagreed, finding the agreements did not consider the ’777 patent and were limited to the U.S. patent and U.S. litigation.
Sanofi-aventis's motion for an interim stay was dismissed. A number of generic manufacturers have since received NOCs for their clopidogrel bisulfate products.
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