Animal Tests of Anti-Inflammatory Drug Failed to Predict Human Risk

Within hours of taking their first dose of an anti-inflammatory drug, six participants of a recent London drug trial were hospitalized with severe swelling and multiple organ failure. The drug had been tested extensively in rabbits, mice, and monkeys, and showed no adverse reactions in the animals. Rather, it produced signs of efficacy.

The episode is reminiscent of the recent case of another anti-inflammatory, Vioxx, which appeared to protect against heart attacks and cardiovascular disease in six different animal species. After human studies showed it to be potentially dangerous, Merck, the manufacturer, decided to test the drug on monkeys.

But monkeys don’t normally experience cardiovascular disease or heart attacks. So Merck decided to create these problems artificially—by damaging otherwise healthy monkeys’ arteries with electrical cautery. Over the four years that it was on the market, Vioxx caused 150,000 heart attacks and strokes and 60,000 deaths across the country.

More than 100,000 Americans die each year from reactions to legal drugs, making it the fifth leading cause of death in the U.S. More than 90 percent of drugs that appear safe and effective in animals never make it to market because they prove either unsafe or ineffective in humans, according to the FDA.