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."
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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