Another one bites the dust: Plavix falls off patent today

Yet another milestone on pharma's journey away from the megablockbuster era: Plavix, the gold-standard clotbuster, goes off patent today. And unlike Pfizer ($PFE), which aggressively plugged its newly off-patent Lipitor, Bristol-Myers Squibb ($BMY) plans to back off Plavix marketing immediately.

Bristol-Myers sells Plavix in partnership with Sanofi ($SNY), and both companies have been girding for this day for years. Thanks to the monopoly Plavix enjoyed, it brought in $6.6 billion in net U.S. sales last year, the company disclosed in its annual report. And in the usual post-patent warning language, the report goes on to say "there will be a rapid, precipitous and material decline" in those sales after today.

Until now, Plavix amounted to almost half of Bristol-Myers' U.S. sales. As The New York Times reports, the drug has generated an estimated $42.8 billion for the company during its 15 years on the market.

But rather than follow Pfizer's pull-out-the-stops example on Lipitor--which may not have yielded as much market share as Pfizer wanted, but did help it hang onto sales it otherwise would have lost--Bristol-Myers is content to offer a limited-time-only discount plan for Plavix patients who want to stick with the brand-name drug.

That could be because Plavix will immediately face a host of generic rivals. Lipitor had only one independent competitor, Ranbaxy Laboratories, which owned 180-day exclusivity for Lipitor copies. The company that qualified for those rights on Plavix copies, Apotex, lost it after an at-risk launch in 2006.

- read the NYT coverage

Special Report: Bristol-Myers Squibb - 10 Largest U.S. Patent Losses