Shares of Shire Pharmaceuticals Group Plc fell as much as 4.4 percent after European and Canadian health regulators raised safety concerns about the Alzheimer's drug Reminyl, which the U.K drugmaker developed with Johnson & Johnson.
The Basingstoke, England-based company's shares fell 22 pence, or 3.5 percent, to 615 pence as of 8:46 a.m. in London trading, after dropping as low as 609 pence.
Clinical trials of 2,000 people evaluating Reminyl as a treatment for mild cognitive impairment showed a higher death rate among patients taking the medication, prompting the review, Johnson & Johnson said in a statement on Friday.
The product, developed from daffodil bulbs, is marketed in 69 countries as a treatment for mild to moderate Alzheimer's disease.
Fifteen of the 20 people who died of causes including cancer and heart attacks during the trials were on Reminyl, Johnson & Johnson said in a statement.
Johnson & Johnson, the maker of products ranging from Tylenol to artificial hips, said it's discussing the results with regulators.
Shares of the New Brunswick, New Jersey-based company fell 64 cents, or 1 percent, to $61.85 on Friday in New York Stock Exchange composite trading.
Canadian and European health regulators are basing the safety reviews on a preliminary analysis of findings presented to regulators and at scientific conferences.
The studies took place in 16 countries.