Pfizer shares fell 15.6 per cent in opening trade today, wiping out nearly $30 billion (£15.2 billion) of market value, after the world's biggest drugmaker scrapped development of its most important experimental medicine.
Pfizer shares fell as low as $23.52 in early trade but later recovered a bit to $24.50, down 12 percent, on the New York Stock Exchange. The stock's year low is $20.27.
The stock was off 10.3 per cent in Frankfurt earlier this morning at €18.62, equivalent to $24.80 and compared to a closing level in New York on Friday of $27.86.
On Saturday Pfizer halted development of Torcetrapib, which was designed to raise levels of "good" HDL cholesterol, after an independent safety monitoring board cited increased deaths and heart problems among patients given the product in a late-stage trial.
With the sudden failure of Torcetrapib, Pfizer's most important experimental product, financial analysts predict shares of the world's largest drugmaker could fall from 5 to 25 per cent on Monday and that the pharmaceutical giant will need to buy other products to fill the void.
Although some rival companies could benefit from the news, experts warned that shares of other drugmakers could be hurt as the setback underscores the risk of drug development and dangers of relying too heavily on potential blockbuster products.
Torcetrapib in earlier clinical trials had boosted HDL cholesterol by 60 per cent, raising hopes that it could greatly reduce the risk of heart attacks and strokes. But it caused slight elevations in blood pressure, itself a major risk of heart disease.
Pfizer, which manufactures the impotence drug Viagra in Ringaskiddy, Co Cork, employs over 1,000 people between its plants in Cork and Dublin.