Last July, theEuropean Medicines Agency (EMA) had refused the placing on the European market of the lecanemabdeveloped jointly by American and Japanese companies marketed under the name Leqembi®, a new innovative biotherapy in the treatment of Alzheimer's disease, causing incomprehension among patient associations. Especially since the medicine is already authorized in the United States s and in Japan since last year and more recently in the United Kingdom, Israel, China and South Korea.
The EMA is now reviewing its copy and has just authorized its placing on the markethowever limiting its prescription to “mild cognitive impairment (problems with memory and thinking) or mild dementia due to Alzheimer's disease (early Alzheimer's disease)” et “in patients who have only one copy of the ApoE4 gene – a risk factor for the disease – or who have none at all”. However, this gene clearly increases the risk of developing the disease, up to doubling it in certain people.
The EMA thus intends to control the sometimes serious side effects of this medication, by targeting people who are least likely to suffer from them. The medicine should be available for French patients within a few months. It will be administered by infusion under medical supervision, Control MRI will be programmed to monitor possible adverse effects.
The Alzheimer Research Foundation gets excited: detailed results at the end of 2022 in the scientific journal New England Journal of Medicine show “a 27% reduction in cognitive decline in patients who followed this treatment compared to the placebo group. This is the first time that an anti-amyloid antibody has proven its effectiveness!”
In fact, this molecule (a monoclonal antibodyin other words a type of protein) has a hitherto unique mode of action since it is capable of reducing and then eliminating amyloid plaques, responsible for Alzheimer's disease. “These plaques are deposited between nerve cells located in the gray matter of the cerebral cortex, causing a dysfunction of the connections between neurons.”, specifies the Alzheimer Research Foundation.
Side effects linked to the way the drug works
This mode of action, however, has a defect: it can be responsible for bleeding in the brainin other words cerebral hemorrhage.
Questioned by the Medical Research Foundation last September, Professor David Wallon, neurologist and director of the Memory, Resource and Research Center at Rouen University Hospital, explains that this serious adverse effect is linked to “an inflammatory reaction in the brain. This will weaken the vessel wall and most often cause microbleeding. Sometimes, when it is more serious, bruising.”
These risks particularly concern people suffering from ApoE4 gene mutation and those whose disease is advanced.
Alzheimer's: what drugs are available today?
Even if the side effects of Leqembi® are documented, this molecule represents such progress in the therapeutic arsenal currently available to doctors that it will certainly revolutionize care.
Because today there is no medicine able to preventto slow down the progression and even less to cure Alzheimer's disease, unlike this new molecule.
“Currently, we are still stuck for 25 years, with a therapeutic strategy that has existed for a long time”, further indicates Professor Wallon.
The four treatments available today are:
- Donepezil (Aricept)
- Rivastigmine (Exelon)
- Galantamine (Reminyl)
- Memantine (Ebixa)
They improve symptoms but do not slow down the progression of amyloid plaques.
Soon other immunotherapies in the treatment of Alzheimer's?
Others immunotherapies are currently in development and we can hope that within a few months, new drugs capable of slowing down or even reversing Alzheimer's disease will obtain their marketing authorizations (AMM, obligatory for the treatment to be distributed, and possibly reimbursed, in France).
The Alzheimer Research Foundation for example puts a lot of hope in donanemab (Kisunla®), developed by the Eli-Lilly laboratory. “Donanemab also belongs to this new category of treatments against Alzheimer's, based on immunotherapy, a process which directly mobilizes immune cells to act on amyloid plaques. The results of phase III, published in August 2023, confirmed the hopes raised by phase II. A slowdown in decline of 35% was observed in treated patients compared to the placebo group..”
The United States, Japan and Great Britain have already approved its placing on the market.
France
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