Recently, the U.S. Food and Drug Administration (FDA) added its strongest warning to the label for blood thinner drug Plavix. Plavix is Bristol-Myers Squibb’s (BMY) lead drug. It is an antiplatelet blood thinner indicated to reduce the risk of heart attack in patients with atherosclerosis (the build-up of plaque and hardening of the arteries). The blockbuster drug is co-marketed by Bristol-Myers Squibb and Sanofi-Aventis (SNY). 

While adding a boxed warning to Plavix, the U.S. agency stated that the blockbuster blood thinner is not effective in patients who fail to metabolize the drug to convert it to its active form thereby exposing them to greater risk of heart attack and stroke. Those patients have a genetic variation that prevents them from making an enzyme needed to break down Plavix. This warning was added to the drug’s label by the FDA in May 2009. However, the agency thought it appropriate to highlight the risk in a boxed warning after reviewing more data.
We note that Plavix must be broken down by a particular liver enzyme for it to work effectively. According to the FDA, 2% to 14 % of people in the U.S. have low levels of the enzyme thereby preventing them from successfully metabolizing Plavix. The FDA stated that the likelihood of being poor metabolizers varies by race. 

The patients can determine if they can process Plavix by taking a genetic test. The U.S. regulatory authority stated that health care professionals should consider alternative dosing of Plavix for the poor metabolizers, or use other anti-platelet therapies to treat them. The sternest FDA warning to Plavix’s label should increase demand for Effient, a blood thinner launched by Eli Lilly & Co. (LLY) in 2009. 

The U.S. regulatory authority stated further that patients should continue taking Plavix unless told otherwise by their doctor. They should consult their health care professional if they have any concerns regarding Bristol’s blockbuster blood thinner. 

Currently, we are Neutral on Bristol-Myers Squibb. The recommendation implies that the stock is expected to perform in line with the overall U.S. equity market over the next six to twelve months. Therefore, we advise investors to retain the stock over this time period.
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