Drug manufacturer Merck knew one of its drugs was killing Alzheimer's patients - but hid the fact from regulators for several years. The drug, the COX-2 painkiller Vioxx (rofecoxib), was finally taken off the market in 2004 after it was found to cause heart attack.
Industry commentators reckon around 60,000 people may have suffered a heart attack after taking the drug, and, earlier this year, Merck made a $4.85 billion settlement to victims' families to end the largest civil suit in legal history.
The drug was originally intended for arthritis sufferers, but the company also thought it might help Alzheimer's victims. But in initial trials, Merck hid the fact that the drug was killing patients - a fact that was lost in papers handed to America's drug regulator, the Food and Drug Administration, in 2004.
Internal papers reported 34 deaths among the 1,069 Alzheimer's patients taking the drug, and yet the studies sent to the FDA said there were 11 'non-drug related' deaths.
(Source: Journal of the American Medical Association, 2008; 299: 1813-7).