The new treatment, which will be marketed under the name Leqembi, is now recommended by the American Medicines Agency (FDA) for patients who have not yet reached an advanced stage of the disease.

Administered intravenously once every two weeks, it is developed by the Japanese pharmaceutical company Eisai, in partnership with the American Biogen.

It represents "an important step forward in our battle to effectively treat Alzheimer's disease," which affects some 6.5 million Americans, the FDA said in a statement.

Leqembi, whose active ingredient is called lecanemab, targets deposits of a protein called beta-amyloid.

While the exact cause of Alzheimer's disease remains poorly understood, patients' brains show amyloid plaques, which form around their neurons and eventually destroy them.

This is what causes the memory loss characteristic of the disease.

In the later stages, patients can no longer carry out daily tasks or hold conversations.

The FDA clearance is based on clinical trial results that showed the drug helped reduce amyloid plaques.

The agency also mentions the results of larger clinical trials, recently published in a scientific journal and from which the FDA expects to receive full data "soon".

Conducted on nearly 1,800 people followed for 18 months, these trials revealed a 27% reduction in cognitive decline in patients treated with lecanemab.

A first for a drug of this type.

But the study also revealed serious adverse effects: some of the patients treated suffered from cerebral hemorrhages.

At least one person who received the treatment has died.

"Given these concerns, whether lecanemab will truly be a game-changer as some say remains unproven," experts wrote in the scientific journal The Lancet in early December.

The FDA included a warning about the risk of bleeding in the drug information.

$26,500 per year

According to a press release from Eisai, approximately 100,000 people could receive this treatment in the United States within three years, given the eligibility criteria (mild cognitive impairment and confirmation of the presence of amyloid plaques).

This is the second Alzheimer's treatment recently approved by the FDA, after Aduhelm in June 2021 (which uses a molecule called aducanumab).

Also produced by the companies Biogen and Esai, and also targeting amyloid plaques, it was the first drug brought to market against this disease in almost two decades.

But its launch had not had the expected success: its authorization had sparked controversy, with some experts criticizing the lack of evidence on its effectiveness.

Its use was later restricted to people with moderate cases of the disease.

A recent US parliamentary report also blamed its exorbitant price tag ($56,000 per year).

The federal Medicare health coverage system, intended for the elderly, had announced that it would only reimburse it if it was taken in the context of clinical trials.

The Leqembi will be launched at a price of 26,500 dollars per year, with the aim of "promoting access for patients, reducing the overall financial burden and supporting the sustainability of the health system", announced Eisai on Friday in a press release.

The question of Medicare coverage for this new treatment has not yet been decided.

"People living with this deadly disease don't have time to wait for a miracle cure," Joanne Pike, president of the Alzheimer's Association, said in a statement, calling for Medicare to agree to reimburse Leqembi.

It has been approved under an accelerated program of the FDA, which makes it possible to authorize more quickly treatments against serious pathologies and which cannot already be effectively treated.

For decades, researchers have failed to achieve a real breakthrough in the fight against Alzheimer's disease, and that is why the authorization of this new class of treatment has raised so many hopes among some.

But no remedy allowing a cure still exists to this day.

© 2023 AFP