Citing the 'interests of patient safety', US drug manufacturer Pfizer said it was stopping all clinical trials of the cholesterol-controlling drug Torcetrapib.
In a statement released at the weekend, the company said it was in the process of notifying all clinical investigators and regulatory authorities, including the Food and Drug Administration.
Pfizer operates six separate manufacturing plants in Cork and Dublin and has an Irish workforce of over 2,000.
The Torcetrapib decision came after Pfizer officials were informed that the independent Data Safety Monitoring Board (DSMB), reviewing a morbidity and mortality study for Torcetrapib, recommended terminating the trial 'because of an imbalance of mortality and cardiovascular events.'
With the sudden failure of the drug, Pfizer's most important experimental product, financial analysts predict shares of the world's largest drugmaker could fall from 5 to 25% today and that Pfizer will need to buy other products to fill the void.
At just after 7pm this evening, Pfizer's share price had tumbled by 11.45% to $24.67.
Shares in the company fell as low as $23.52 in early trade but have since recovered some ground on the New York Stock Exchange. The stock's year low is $20.27.
The company is in the process of asking all clinical investigators involved in the programme to inform patient participants to stop taking the medication immediately.
'While the DSMB information we received was both surprising and disappointing, our focus is on the best interests of patients and making sure all this information is communicated to appropriate medical and regulatory authorities as quickly as possible,' said Pfizer CEO Jeffrey Kindler.
He added the drug maker understood 'the challenge that this represents and we will respond quickly and aggressively to it.' Pfizer said it would accelerate plans to improve operations and cut costs in view of the Torcetrapib setback and reaffirmed plans to introduce about six products a year, starting in 2010.
Investors were counting on Torcetrapib to be approved before the patent expires by 2010 or 2011 on Lipitor, Pfizer's $13 billion-a-year pill that cuts levels of 'bad' LDL cholesterol, and make up for most of Lipitor's lost sales.
Torcetrapib in earlier clinical trials had raised 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.
