Pfizer's Lipitor safer than Merck's Simvastatin: Study

In a relief to the declining year over year sales of Pfizer's cholesterol drug Lipitor, a new study showed that the drug has significantly lower relative risk of experiencing any cardiovascular event, a heart attack, or revascularisation compared to patients who took simvastatin, Merck's hypercholesterolemia drug. This positive result is expected to boost the sales of Lipitor.

The observational study conducted in new statin users without cardiovascular disease, showed that patients taking Lipitor had a significant 12 per cent lower relative risk of experiencing a cardiovascular event. In a secondary analysis, patients taking Lipitor had a significant 15 per cent lower relative risk of experiencing a heart attack, and a significant 12 per cent lower relative risk of revascularisation compared to patients taking simvastatin. These differences were evident in patients taking doses of Lipitor or simvastatin that would have been expected to deliver similar LDL reductions (Lipitor 10 mg or 20 mg or simvastatin 20 mg or 40 mg). There was no significant difference between the groups in stroke or mini-stroke.

"An important concern for clinicians, as well as for public health in general, is whether patients treated with different statins will experience different cardiovascular outcomes," said Dr JoAnne M. Foody, associate professor of medicine at Harvard Medical School and director of the Cardiovascular Wellness Center at Brigham and Women's/Faulkner Hospitals, Boston. "This study suggests that there may be differences in cardiovascular outcomes between atorvastatin and simvastatin. Given the large number of patients receiving statin therapy, the availability of generic statins, and the clinical and economic burden of cardiovascular events, the results of this observational study could have significant public health implications."

This is one of the largest observational studies to date to examine cardiovascular outcomes in patients without cardiovascular disease treated with different statins in routine clinical practice.

The study was a retrospective analysis using anonymous patient-level health plan data from IMS Health. At the time of the analysis, the database, known as the PharMetrics Patient-Centric Database, included fully adjudicated medical and pharmacy claims for 52 million individual patients from 92 health plans across the US.

The analysis examined claims from 219,631 patients without cardiovascular disease who initiated statin therapy from January 2003 to September 2005 and who were enrolled in US health plans (168,973 patients began therapy with Lipitor 10 mg or 20 mg daily and 50,658 patients began therapy with simvastatin 20 mg or 40 mg daily). Patients were followed for a median of one and a half years.

A cardiovascular event was defined as the time to first hospitalisation due to a heart attack, chest pain or coronary artery disease, stroke, mini-stroke, vascular disease, or revascularisation.

Since patients were not randomly assigned to each group, the two treatment groups were adjusted based on certain risk factors, such as age, gender, co-morbidities and prior healthcare cost. Various statistical methods were employed to address residual imbalances.

The results of this study complement the large body of evidence from multiple clinical trials demonstrating the cardiovascular benefits of Lipitor and support findings from previously published observational studies.

According to Dr. Michael Berelowitz, senior vice president, global medical division, Pfizer, "There has been widespread encouragement by managed care companies and governments for physicians to prescribe generic statins based on what is believed to be comparable LDL-lowering doses, assuming that this will result in similar cardiovascular benefits. This analysis calls into question those assumptions and those policies and reaffirms that treatment decisions need to be made by physicians based on a patient's risk for developing cardiovascular disease."

Lipitor is the most prescribed cholesterol-lowering therapy in the world, with nearly 144 million patient-years of experience. It is supported by an extensive clinical trial program involving more than 400 ongoing and completed trials with more than 80,000 patients. There have been more than ten cardiovascular outcomes trials with more then 50,000 patients.