US panel set to vote on experimental Alzheimer's drug

A US government expert committee was set to vote Friday on whether to recommend the approval of the first new Alzheimer's drug in almost two decades.

The decisions reached by such panels, while nonbinding, are often accepted by the Food and Drug Administration.

If it is eventually approved, Biogen's aducanumab would be the first drug ever to treat cognitive decline associated with Alzheimer's -- a major medical milestone.

Some in the research community, however, say the evidence in favor of aducanumab is not yet clear-cut and more work needs to be done to prove it really works.

There have been two major late-stage clinical trials to test aducanumab, with one demonstrating clear benefits from taking the intravenous medicine -- and the other finding apparently negative results.

The expert committee released several lengthy documents ahead of Friday's meeting, finding that the results of one of the trials was indeed "highly persuasive."

Of the other trial, it said it had agreed with Biogen that certain factors, such as a subset of patients who had far more severe disease, had skewed the results. When this group was removed from the analysis, the findings were also positive.

Thomas Wisniewski, director of the Alzheimer's Disease Center at NYU Langone Health, told AFP: "There have been no disease modifying agents for Alzheimer's disease at all, and this promises to be such an agent."

Wisniewski, who oversaw part of the trial that was clearly positive, said brain imaging showed the drug worked as intended and patients benefited, as shown by results on cognitive tests.

He added a known side effect was a form of brain swelling, but said the condition was "quite manageable."

However, other researchers were not convinced.

"Perfection may be the enemy of the good, but for aducanumab, the evidence doesn't even rise to 'good'," wrote David Knopman of the Mayo Clinic in a document submitted to the panel.

He added: "The straightforward solution is this: Biogen needs to do a third trial with high dose aducanumab."

Aducanumab is a monoclonal antibody that targets the build-up of a protein called beta-amyloid in the brain tissue of Alzheimer's patients.

Alzheimer's disease comes about from an excessive accumulation of these proteins in some people's brains as they age and their immune systems decline.

Providing such patients antibodies could therefore be a means to restore some of their capacity to clear the plaque build-up.

Alzheimer's, the most common form of dementia, is thought to affect 50 million people worldwide and usually starts over the age of 65.

It progressively destroys brain tissue, robbing people of their memory, leaving them disoriented and at times unable to carry out everyday tasks.

It's also associated with dramatic mood swings and trouble communicating.