The drug companies have been holding out on us again. This time they've been caught suppressing evidence about the cholesterol-lowering drug Zetia (ezetimibe), which demonstrates it is ineffective.
The manufacturer, Merck and Schering-Plough, revealed the results only when a US Congressional inquiry forced them to do so. The inquiry was set up to investigate why the company had not published the results of the trial that had taken place two years earlier.
The study, which involved 356 people with high cholesterol, discovered that the drug wasn't effective, and that any improvements in the patients were down to another drug, simvastatin.
Nonetheless, Zetia has been a very successful drug, with annual sales of around $5bn (lb2.6bn). With that to protect, Merck took out full page advertisements in America's press, and urged existing Zetia patients not to panic (drug speak for stop taking the drug). The advertisement explained there was "confusion" about the drug, and that people shouldn't rely on the results of just one trial.
Silly Congress. This is probably why they suppressed the results in the first place.
(Source: British Medical Journal, 2008; 336: 180).