Washington (AFP)

The US regulator on Monday announced that it would authorize a new drug against Alzheimer's disease, for the first time in nearly two decades.

"This clearance is significant in many ways," the United States Drugs Agency (FDA) said in a statement.

Named Aduhelm and produced by the pharmaceutical company Biogen, it is the "first approved treatment for Alzheimer's disease since 2003," the agency said.

Above all, it is the first treatment directed at the cause of the disease, "the presence of beta-amyloid plaques in the brain", and not just the symptoms it causes, she added.

"We are delighted with this historic decision", reacted in a tweet the American organization Alzheimer Association.

In November, however, an expert committee ruled against authorizing this treatment, judging that it had not sufficiently demonstrated its effectiveness.

A non-binding opinion, but it is rare for the FDA to dispense with it.

The committee had studied data from two studies: one large clinical trial concluded that the drug from Biogen laboratories was effective, while another had given negative results.

But "the FDA has determined that there is substantial evidence that Aduhelm reduces beta-amyloid plaques in the brain and that reducing these plaques is reasonably likely to result in significant benefits for patients," a- she declared.

The Agency thus "concluded that the benefits (...) outweigh the risks" of taking this drug, she added.

The FDA also used a fast-track procedure that only grants the product conditional authorization - a possibility that had not been studied by the committee.

"The FDA asks Biogen to conduct post-authorization clinical trials to verify the clinical benefits of the drug," said the US regulator.

"If the drug does not work as expected, we may take steps to take it off the market."

- Glimmer of hope -

Almost 6 million Americans live with Alzheimer's, which is the sixth leading cause of death in the United States.

The disease gradually robs the memory of affected patients, who in the later stages of the disease can no longer perform daily tasks or hold conversations.

"The need for treatment is urgent," hammered the FDA.

The drug uses a molecule, called aducanumab.

These are monoclonal antibodies that aim to dissolve aggregates of this protein, beta-amyloid, which accumulates and creates plaques in the brain tissue of Alzheimer's patients.

This target is one of the main avenues explored by research against this degenerative pathology.

But treatment studies have suffered setbacks in recent years, and no cure exists to date.

This is why this drug was seen as a silver lining.

Despite everything, in accordance with the great debate that agitates the scientific community around this treatment, some experts on Monday tempered the enthusiasm.

"While I am happy that aducanumab has received clearance, we need to be clear that at best this drug will have marginal benefit that will only help some carefully chosen patients," said John Hardy, professor of neuroscience. at University College London.

"We will need better medicine in the future."

Biogen's stock was temporarily suspended on the Wall Street Stock Exchange at the time of the announcement in order, it seems, to prevent too much volatility.

© 2021 AFP