The market for one or more drugs once morest Alzheimer’s disease is immense. And yet, it seems very difficult to develop a molecule that can block the evolution of the disease. The rare treatments marketed to date have not been lucky. They were either withdrawn or withdrawn from the market for inefficiency. “The problem is that when you don’t know a disease very well, it is difficult to find a treatment,” says Professor Philippe Amouyel. And then from the moment the disease is diagnosed, it is often already evolving for a long time and the destruction of neurons is irreversible. »
Alzheimer’s disease is characterized by a loss of neurons, with an accumulation of so-called “amyloid” protein plaques in the brain and neurofibrillary degeneration. It begins with the accumulation of this amyloid protein. But is this accumulation cause or consequence of the disease? Does eliminating this protein also eliminate the disease? Attempts to vaccinate once morest this protein in mice suffering from a form of cerebral degeneration have shown an improvement in their condition. But the tests on human beings unfortunately ended in such serious complications that this track was abandoned.
A lead: a monoclonal antibody
A new drug once morest Alzheimer’s, lecanemab, authorized in January 2023 in the United States, is a monoclonal antibody that blocks the amyloid protein. Trial results published in November 2022 reveal that this drug decreases cerebral amyloid protein overload, assessed by imaging, in patients with early stage disease.
The effect on disorders is much less spectacular. On a scale of increasing symptoms ranging from 1 to 18, the drug made it possible to obtain, in eighteen months, a difference of 0.45 points less for treated patients compared to those who were not treated. “If we make the assumption that this effect persists in the long term, the drug following six years, might make it possible to prolong the period without dependence from sixteen to nineteen months. The biological effect is clear, the clinical effect remains moderate,” notes Professor Amouyel.
There are also side effects, 17% cerebral micro-haemorrhages, 13% cerebral oedemas. Finally, and this is not the least constraint, this treatment will probably cost per patient between 25,000 and 30,000 euros per year. The European Medicines Agency is studying the file.
