Problems With Alzheimer’s Vaccine Halt Shots
A dozen volunteers inoculated with a highly touted experimental vaccine designed to reverse the course of Alzheimer’s disease have fallen seriously ill with brain inflammation, forcing the vaccine’s manufacturer to stop giving the shots and raising doubts about the product’s clinical potential, according to sources familiar with the study.
The vaccine, made by the Irish pharmaceutical company Elan and known by its code name AN-1792, had generated unusually intense enthusiasm among scientists and patient advocates during the last two years, as experiments with mice suggested it could halt the progression of Alzheimer’s and perhaps cure the deadly disease.
The ailment gradually robs people of their mind. It affects 2 million to 4 million Americans and is expected to affect 15 million by 2030. Even today’s best treatments have a very modest effect.
Taking an immunological approach to treating the disease, the vaccine aims to elicit an immune system attack against “beta amyloid,” the brain protein believed to be at the root of Alzheimer’s.
Company officials have released few details about the problems. A spokesman said an independent committee is reviewing data from the study, which has enrolled about 360 people in four European countries and 11 U.S. cities who have mild to moderate Alzheimer’s.
But sources familiar with the study, including some who have been in contact with Elan officials, said there is little question that the vaccine triggered the brain reactions, which some called encephalitis (an inflammation of the brain) and another source called “meningoencephalitis” (an inflammation of the brain and surrounding membranes).
Some scientists had warned that the vaccine might trigger such complications or even exacerbate Alzheimer’s, a disease some believe is caused by natural inflammatory processes.
One such critic, Trey Sunderland, chief of the geriatric psychiatry branch at the National Institute of Mental Health, said Thursday that the vaccine may have directly caused the encephalitis in volunteers or it may have caused a disruption of blood vessels in their brains. That would allow viruses or other infectious agents to enter and cause encephalitis.
Elan, which is developing the vaccine with Wyeth, a pharmaceutical division of American Home Products Corp. of Madison, N.J., would not say Thursday how quickly it had halted inoculations after the first few patients were diagnosed.
A company spokesman said only doctors at individual test sites could address that issue, but officials at several sites Thursday said they had been told by the company not to talk to reporters.
