LOS ANGELES, CA (Catholic Online) - Aspirin was the traditional treatment for preventing blood clots that eventually led to heart attacks and stroke before Plavix came around in 1997. However, combining both aspirin and Plavix has "tremendously improved" the results, according to Dr. Nissen, chairman of cardiovascular medicine at the Cleveland Clinic. But now, Plavix is coming to an end due to losing its patent protection on Thursday. Bristol-Myers Squibb, which sells Plavix in the United States under a partnership with Sanofi-Aventis, is no longer planning to actively promote the drug.

"This is one of the behemoth drugs that really defined the drug industry in the '90s," said Catherine J. Arnold, an analyst for Credit Suisse.

Bristol-Myers is not the only company to face the loss of a best-selling drug. At least 19 others are to lose patent protection this year, expected to cost the pharmaceutical industry about $38.5 billion in lost sales. Now about 80% of prescriptions written in the U.S. are now filled with generic drugs.

In 2011, Plavix brought in roughly $7.1 billion in net sales, which accounted for a third of the total revenue for the year. In 15 years, Plavix has made over $42.8 billion for Bristol-Myers. It is the biggest name-brand drug to lose patent protection since Lipitor, made by Pfizer.

"We expect a rapid, precipitous and material decline in Plavix net sales," company officials wrote in the 2011 annual report. Analysts expect the price of generic alternatives to be substantially lower than brand-name Plavix.

Drug prices usually take a few months to drop because the first company to file an application with the drug company is given the right to market the drug for the first six months. The Canadian drug producer, Apotex, gave up its right after it sold unauthorized generic versions of the drug in 2006. When Apotex distributed a six-month supply of Plavix before a judge commanded the company to stop, Plavix lost about $1 billion in sales.

Bristol-Myers paid more than $3 million in civil and criminal fines after the Justice Department accused the company of having a secret deal with Apotex to delay its own generic version of the drug. Seven companies have received the approval to market the generic drug, due to Apotex losing its exclusivity. In 2008, Dr. Reddy's Laboratories received approval to sell a 75-milligram dose, however it has been prevented from doing so under court order. The agency usually gives the final approval to generic drug companies on the day the brand-name loses its patent protection.

Last year, Bristol-Myers got the approval of a drug to treat melanoma known as Yervoy. The Federal Drug Administration is expected to decide on the approval of a blood-thinning drug, Eliquis, which Bristol-Myers is making with Pfizer. Eliquis is in a new class of drug that helps prevent strokes in people with the heart arrhythmia called atrial fibrillation. If it is approved, it is expected to bring in billions of dollars in sales.

"It really turned out to not just be rhetoric," Ms. Arnold of Credit Suisse said. "They really have created a confidence in investors that there is life beyond Plavix."

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