A cure for Alzheimer's: hope put on hold

The European approval of Leqembi (lecanemab) breaks new ground in the treatment of Alzheimer's disease in Luxembourg, where up to 2,000 people could theoretically benefit from it. It's not just another drug to alleviate symptoms - it's an attempt to stop the very mechanism of brain destruction by attacking amyloid deposits, a key link in Alzheimer's pathogenesis. But the promise of a scientific breakthrough hides severe limitations.

Professor Michael Heneka, who heads the Centre for Systems Biomedicine at the University of Luxembourg, explains: the effect of Leqembi is only possible within a narrow time frame - decades after the amyloid accumulation begins, but before significant cognitive damage occurs. In other words, to begin treatment, a patient needs to be diagnosed with the disease long before its obvious symptoms appear. This raises questions about how many people will actually benefit from the therapy - even among the 1,500 who are formally part of the target group.

In addition, the drug has no effect on other parallel neurodegenerative processes that continue to destroy the brain. Thus, Leqembi slows down but does not stop the disease.

Another sticking point is safety. The drug carries a risk of serious side effects, including brain swelling and haemorrhages. People with certain genetic markers - carriers of the APOE ε4 gene variant, for example - are excluded from potential patients because the risk of complications is too high for them. This genetic "sieve" further narrows the pool of those who are eligible for therapy.

Even those who fulfil the medical criteria will have to undergo four mandatory medical examinations during the first year of treatment. This is necessary for continuous monitoring of side effects. In addition, the presence of other medical conditions may automatically make a patient ineligible for Leqembi.

The cost of therapy is about 26,000 euros per year. Before the drug becomes available in Luxembourg, it must be approved by the Belgian regulator (on whose decisions the country is guided), undergo price negotiations, and be included in the national treatment protocol. The Ministry of Health expects the drug to become available by the middle of the year at the earliest.

For those who wish to start treatment earlier, there is an option to make an individual request to the National Health Insurance Fund (CNS), but such cases will be dealt with separately.

Scientifically, Leqembi is an important step forward: it is the first drug recognised in the EU that affects the pathogenesis of Alzheimer's. It offers a chance, however small, of slowing the disease. But practical implementation so far resembles a narrow bottle neck: a multitude of filters - from the time of diagnosis to genetics and comorbidities - leave most patients with little hope of a cure.