New Alzheimer’s treatments: revolution or illusion?

Two new drugs that promise to slow the disease Alzheimer are causing controversy in the medical world. Some see them as an unprecedented opportunity. Others see them as a new disappointment after decades of fruitless research.

These treatments, the Leqembi and the Kisunla are “a turning point,” biologist John Hardy, whose work has guided much of the research into Alzheimer’s since the 1990s, told AFP.

But for Rob Howard, a specialist at University College London, they are creating “Unrealistic false hopes for Alzheimer’s patients and their families”.

These statements sum up the often bitter positions on these two recently introduced drugs for Alzheimer’s disease, the most common dementia with tens of millions of patients worldwide.

One is Leqembi, based on the lecanemab molecule and developed by Biogen and Eisai laboratories. The other is Kisunla, based on the donanemab antibody and designed by Eli Lilly.

The reception of these drugs, with a similar profile, has been uneven depending on the country.

The United States has approved both, but the European Union recently refused to approve lecanemab, suggesting a similar decision could be made for donanemab.

At the end of August, the United Kingdom opted for a middle path: it approved lecanemab, but refused to reimburse it for use by the public health system.

The controversy lies in that, Although they are the most effective drugs ever seen against Alzheimer’s, their effectiveness is very limited, with a 30% reduction in cognitive decline at the beginning of the disease..

The figure may seem high, but it is a small difference considering that it is based only on the year-and-a-half period during which the laboratories carried out their tests.

“The benefits are so small that they are almost invisible.”, afirma Howard.

Astronomical cost

For critics, the improvement is small and the risk high: The drugs can cause cerebral edema, which is occasionally fatal.

Plus, the cost is astronomical.

At the price requested by Biogen/Eisai in the United States, Treating all potential patients in the EU with lecanemab would cost the public coffers an unaffordable 133 billion euros (almost 150 billion dollars).as published in the Lancet magazine in 2023.

Proponents of these treatments, including many neurologists, argue that they can offer patients valuable months of autonomy.

They also believe that their effectiveness could be increased if they are given earlier.now that science is rapidly advancing in the early diagnosis of this disease.

Beyond the medical debate, the EU and the UK are also accused of contributing to healthcare inequality: “the richest patients will go to the US,” says Hardy.

The debate overlaps in part with discussions about the “amyloid cascade,” a hypothesis for the origin of the disease described in 1992 by Hardy.

This theory states that the presence of amyloid protein plaques, a constant in the brains of these patients, is not a symptom like any other, but rather the factor that causes dementia.

For this reason, most of the drugs developed decades ago to combat Alzheimer’s, including Leqembi and Kisunla, attack these plaques.

This partly explains the virulence of some detractors, who recall other treatments previously advocated by doctors and associations despite their obvious ineffectiveness.

Pressure from families

“Why would wise societies support drugs that are of no interest to them?” asks Christian Guy-Coichard, president of Formindep, a body that monitors conflicts of interest.

This pharmacist believes that There is excessive closeness between researchers, associations and laboratories.

Asked by AFP, France Alzheimer’s, the main French patient association, insists that it receives very little funding from Biogen/Eisai or Eli Lilly and, on the other hand, a lot of pressure from families.

“They don’t understand (the EU’s decision), they say to us: ‘But did they react?'” says its managing director Benoît Durand.

But in the same industry, some actors admit that the past does not inspire confidence.

An anonymous Eli Lilly doctor criticizes Biogen for having previously sold a treatment, Aduhelm, controversially approved in the United States in 2021 and then withdrawn.

“Aduhelm’s studies were not really neat (…) That did a lot of damage and sowed chaos in the discipline”this source says.

But at the same time, this doctor calls for looking more to the future than to the past and defends the interest of these new treatments.

However, like many specialists, he admits that it is worth exploring mechanisms other than the amyloid cascade.

“Given the complexity of Alzheimer’s disease, It is unlikely that treatments (that follow the same path) can obtain more important effects” than Leqembi and Kisunlanumerous experts said in a letter published in the Journal of Alzheimer’s Disease Prevention in August.