A generic form of the Bristol-Myers Squibb anticoagulant Plavix saw launch by Canadian generic drug maker Apotex, delivering a big blow to BMS. The launch came today, shortly after BMS noted in a regulatory filing that it anticipates a generic form of clopidogrel “shortly.” And last week pharmacy benefit management (PBM) concern Medco Health Solutions raised its full year guidance on “market chatter” about a coming generic form of Plavix. Plavix had 2005 global sales of $5.9 billion, including $3.7 billion US, making it the second-biggest selling drug in the world behind Pfizer’s Lipitor. In separate statements, BMS and co-marketer Sanofi-Aventis said they are considering legal options, including seeking injunctive relief. In its quarterly SEC filing today, BMS also said that Apotex terminated its obligation to pursue a legal settlement of ongoing Plavix patent litigation as of July 31.Apotex, in a statement, called its clopidogrel launch “the largest and most successful” in generics history. The company added that it expects the courts will find the Plavix patent invalid.In an attempt to end the patent-infringement case, the three firms agreed on a settlement that would have delayed Apotex’s generic launch until 2011, several months prior to the patent expiry. But the agreement was blocked by several state attorneys general.Under terms of the failed settlement, certain terms of which BMS and Sanofi are still bound by, the two can’t seek an injunction for five days. Even if BMS gets an injunction against Apotex, its US Plavix sales would suffer substantially. About 50% of Plavix is dispensed by mail. The PBM Express Scripts said it expected to receive its first shipment of generic Plavix either today or Wednesday and to begin dispensing from its mail-delivery pharmacies either Wednesday or Thursday, according to The Wall Street Journal.For Apotex, launching its generic before a court decision in the patent case poses a risk. Still, settlement terms limit BMS’ and Sanofi’s damages to a range of 40% to 50% of net sales from a generic, rather than the generally accepted three-fold amount.As previously reported in MM&M, Apotex has 180 days of market exclusivity for the US market.