The gloves are off. Overnight, Pfizer came out with a new study on the world's top-selling drug, Lipitor, for cholesterol. The company says if you switch from its drug to generic Zocor you've got a 30% greater chance of dying from a heart attack, stroke or some other "major cardiovascular" event.
Pfizer did what's called an "observational study". In other words, it's not a gold-standard, randomized, placebo-controlled clinical trial. Researchers looked at the medical records of more than 11,500 patients in the UK--2,500 took Lipitor and then switched to Zocor, more than 9,000 stayed on Lipitor--from 1997 to 2005. And they concluded that making the switch resulted in a statistically significant 30% increase in the relative risk of having serious heart trouble. In the press release though Pfizer says, "As with all observational studies, the findings should be regarded as hypothesis generating."
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Lipitor is under intense competitive pressure from cheaper, generic Zocor and brand name drugs like AstraZeneca's Crestor and Merck and Schering-Plough's Vytorin. U.S. sales of Lipitor in the second quarter plummeted 25% as doctors and insurers switch more patients from the Pfizer drug to a generic. In the most recent week Deutsche Bank analyst Barbara Ryan tells clients in a research note that new Lipitor prescriptions were down 1.5% and total Lipitor prescriptions dipped 1.4%. Since generic Zocor hit the market last year Ryan says Lipitor's market share has fallen about 10%. Nonetheless, Lipitor is still, by a wide margin, the biggest prescription drug in history.
Investors are not putting much stock in the study. In early trading, PFE shares are down again.
Full disclosure:I have been taking 10mg of Lipitor for the past couple of years. I have received a letter from Medco asking me to consider switching to generic Zocor, but since periodic blood tests show Lipitor as well as a regular exercise regimen and a cocktail of homeopathic remedies (CholestOff, red yeast rice capsules, flaxseed oil capsules, garlic tablets--and I am not endorsing any of these) are apparently lowering my cholesterol, I continue to pay the higher co-pay for Lipitor.
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