Clopidogrel Bisulphate (Plavix): Canadian Supreme court upheld innovator Sanofi’s patent

In a significant decision, the Canadian supreme court has sided with innovator companies on patent evergreening. In a 7-0 judgment today, the Court rejected a request from generic company Apotex to invalidate a competitor's patent for an anti-coagulant drug used to combat cardio-vascular degeneration. Court concluded that innovator took lot of effort to develop New chemical moiety like Clopidogrel. Sanofi spent millions of dollars and even abandoned the project before discovering the compound that led to the development of Plavix.The patent in dispute was challenged by Apotex, which claimed that Sanofi's following patent:

CA1336777(equivalent to US4847265) (Expiry:2012) - Which covers Dextro-rotatory isomer of methyl alpha-5(4,5,6,7-tetrahydro(3,2-c)thieno pyridyl) (2-chlorophenyl)-acetate substantially separated from the levo-rotatory isomer and its pharmaceutically acceptable salts.Is obvious as per earlier expired patent, which covers Clopidogrel genrically .

Apotex attorney said during trial that Sanofi’s scientists used known research methods on a large group of compounds the company had patented earlier to come up with the key ingredient in Clopidogrel as per doctrine of selection. Apotex argued that the doctrine of selection is contradictory to established principles of patent law and urged the court to abolish the practice that allows innovator companies to patent a large group of generic structures and then obtain new patents with enhanced life on individual components that prove useful.

Plavix last year regained its title as the world's second best-selling drug, behind Pfizer Inc.'s Lipitor, with $8.1 billion in global sales.Apotex claims that clopidogrel bisulfate, the active ingredient, was covered by a US4529596 (Expired in 2003). Innovator Sanofi maintains that the earlier patent covered a whole class of generic compounds (Genus) and the discovery of clopidogrel bisulfate was serendipity.Researchers separated the racemic compound into individual enatiomenrs. Sanofi further stressed that resolution of enatiomer resulted into therapeutically active enatiomer.The expert during testimony stressed that abolishing the principle of the doctrine of selection would stifle research and innovation. Supreme court panel announced it would reserve a decision.
The court sided with innovator and concluded that earlier expitred patent covers large group of genus and selection of Clopidogrel was not obvious.
Court concluded that a selection patent that claims a compound that is patentably distinct from the genus patent would not be invalid for obviousness or double patenting. In Clopidogrel case, out of the many compounds (2.5 lakh compounds) predicted to be effective as exhibiting platelet aggregation inhibiting activity in the ‘875 patent, it was found that the dextro-rotatory isomer of the racemate relevant in this case had beneficial properties over both the racemate and the levo-rotatory isomer. Accordingly, the claims in the ‘777 patent reflect a patentably distinct compound from the compounds in the ‘875 patent. As a result, there is no basis for a challenge based on “obviousness” double patenting.
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Court’s decision Here