Eleven patients die in Eisai drug trial

CHICAGO (Reuters) – Eleven patients have died while taking
Alzheimer’s disease drug Aricept during a clinical trial,
Japan’s Eisai Co., which makes the medicine, said on Thursday.

There were no deaths among patients who were taking a
placebo, said Eisai, which markets Aricept with Pfizer Inc.

The drug treats mild to moderate Alzheimer’s disease, but
was being tested in patients with vascular dementia, the second
most common form of dementia after Alzheimer’s disease.

The deaths were among 648 patients who received Aricept
once daily for 24 weeks. That compared with no deaths in the
326 patients receiving placebos, Eisai said.

The difference in mortality between the groups was
statistically significant, meaning it probably was not due to
chance.

The trial is a Phase 3 study, the final period of testing
before companies present proposals to regulators for approval.

Applications to expand the use of Aricept to vascular
dementia, which is caused by a stroke or diseased blood
vessels, is pending in the United States, said Eisai
spokeswoman Judee Shuler.

“We are still working with the FDA (U.S. Food and Drug
Administration), discussing it,” she said.

The company does not think the study changes the risk
profile of the drug, she added. Pfizer officials did not have a
comment.

Sam Gandy, chairman of medical and scientific advisory
council of the Alzheimer’s Association, said the findings
“raise a red flag” but that it cannot negate 10 years of the
drug’s safety record on the market.

“It is very surprising, and it is of course of concern, but
it is really outside the typical experience with the drug,”
said Gandy, who is also director of the neuroscience institute
at Thomas Jefferson University in Philadelphia. “I would
absolutely restrict its use to what it is approved for in
Alzheimer’s.”

Aricept was considered innovative when approved in the mid-
1990s, improving upon a widely-used drug that caused liver
toxicity, he said.

The study was conducted in nine countries and involved only
patients with vascular dementia, with no prior diagnosis of
Alzheimer’s disease. Most had a history of stroke or heart
disease, and were therefore also taking medicines to treat
their cardiovascular problems.

Eisai said it had not expected the absence of deaths in the
placebo group, considering the age and sickness of patients in
the study. By contrast, the company said there had been a
combined 2 percent incidence of death among patients taking
placebos in two prior vascular dementia trials.

The incidence of death in the Aricept group was similar to
that in prior trials. But in these earlier studies, the
difference between placebo deaths were not statistically
significant.

Patients taking Aricept in the latest trial showed a
statistically significant improvement in cognitive function,
compared with those taking placebos. But the Aricept group
showed no significant benefit on another primary measure of the
trial, known as global function.

The drug is approved for vascular dementia in a half-dozen
smaller markets, including South Korea and India.

Pfizer shares were up 8 cents at $26.03 in midday New York
Stock Exchange trade. In Tokyo, Eisai closed down 0.4 percent.