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news.Shares in Pfizer have fallen over 1.5% after two separate studies cast doubt on its blockbuster cholesterol-lowering drug, Lipitor.
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In the first of the two studies, results showed that Merck/Schering-Plough’s Vytorin (ezetimibe/simvastatin) was better than Lipitor (atorvastatin calcium) at lowering LDL, or ‘bad’, cholesterol across the dosing ranges studied. At the most commonly used starting doses of these two therapies, Vytorin 10/20mg decreased LDL cholesterol by 51% compared with 36% for Lipitor 10mg.
In a subgroup of high-risk patients, significant differences in LDL cholesterol reductions at these starting doses resulted in more patients achieving a goal of less than 100mg/dL with Vytorin as compared to Lipitor. Specifically, 82% of high risk patients on Vytorin 10/20mg achieved an LDL cholesterol goal of less than 100mg/dL as compared to only 47% for patients on Lipitor 10mg.
Results for a higher dose showed that Vytorin 10/40mg decreased LDL cholesterol by 59% compared to 49% for Lipitor 40mg in the subgroup of high risk patients. In this study, 57% of high risk patients taking Vytorin 10/40mg achieved a LDL cholesterol lowering of less than 70mg/dL as compared to 23% of the patients taking Lipitor 40mg.
The news boosted shares in both Merck & Co and Schering-Plough slightly.
In the second study, although coronary heart disease (CHD) patients who reduced LDL cholesterol to very low levels with Lipitor showed a significant decrease in heart attack and stroke compared to those lowering these levels to recommended levels, patient deaths from other causes, including cancer, rose slightly.
As quoted by Reuters, Bertram Pitt of the University of Michigan School of Medicine stated, “Although this increase in deaths from noncardiovascular causes could be due to chance, it is a matter of concern.”
The five-year trial, named TNT, involved 10,000 patients with established coronary heart disease and elevated LDL levels. The study assessed whether high-dose Lipitor patients who aggressively lowered their LDL-cholesterol levels to well below the current guidelines (100mg/dL) would experience additional cardiovascular benefits compared to Lipitor patients who maintained their LDL-cholesterol at recommended levels.
Patients who received 80mg doses of Lipitor had 22% fewer cardiovascular events, including CHD death, non-fatal heart attacks, resuscitated cardiac arrest, and fatal or non-fatal strokes compared to patients who took 10mg of Lipitor. In addition, patients treated with high-dose Lipitor had 25% fewer fatal or non-fatal strokes compared to those treated with just 10mg of Lipitor.