2023-07-09 05:32:53
Posted 1:32 a.m. Updated 6:00 a.m.
How does the drug work?
Designed by the Japanese pharmaceutical companies Eisai and American Biogen, Leqembi is composed of a molecule called lecanemab. “It’s like Tylenol and acetaminophen,” says Étienne Aumont, neuroscience researcher at UQAM. Lecanemab can be described as a monoclonal antibody, which is a large molecule with two ends. One of these ends binds to a specific protein, in this case amyloid beta, and the other end signals the immune system that there is something to clean up. “The monoclonal antibody will therefore allow the immune system to get rid of the beta amyloid protein, which contributes to the initial progression of Alzheimer’s disease. Leqembi is given every two weeks as an intravenous solution.
How effective is Leqembi?
Leqembi makes it possible to slow down, to a certain extent, the cognitive decline of patients at an early stage of Alzheimer’s disease. It can be given to people who have mild symptoms of cognitive decline. The study that led to the approval of Leqembi by the FDA was published last January in the journal The New England Journal of Medicine.
According to the results of the Clarity AD clinical trial, in which 1,795 patients participated, Leqembi slowed cognitive decline by 27% over an 18-month period.
“It’s a good start, but it’s not phenomenal,” explained Étienne Aumont in an interview. We must also not forget that this is an 18-month clinical trial. It would be interesting to know if the drug slows the progression for three, four, five, six years. And that’s not to mention the side effects, which are not insignificant, according to the researcher.
What are the side effects of Leqembi?
The FDA has granted full approval for Leqembi. According to the agency, the scientific evidence is strong about its potential benefits. However, the label on the product contains a black-box warning, the highest warning level, according to the FDA. Indeed, in rare cases, Leqembi can have very serious effects, which can even be fatal.
During the clinical trial, nearly 13% of patients who received Leqembi experienced swelling of the brain, most often mild or moderate. In comparison, less than 2% of patients who received the placebo experienced such swelling.
Most brain swellings have not caused any symptoms. They usually appeared soon after starting use and resolved within a few months. About 17% of patients given Leqembi experienced bleeding in the brain, compared with 9% of patients given placebo.
According to Étienne Aumont, these side effects underline the importance of closely monitoring the patients treated. “We need to do medical imaging to check that there are not too many bleeding starts, small hemorrhages in the brain. It can happen when you get rid of the amyloid. »
Is the game really worth the candle?
“You have to carefully weigh the risks and the benefits,” explains Frédéric Calon, professor at the Faculty of Pharmacy at Université Laval and neuroscience researcher at the Center de recherche du CHU de Québec-Université Laval. Although not revolutionary, the positive effects are statistically significant, according to the researcher. As for adverse effects, the most serious effects are rather rare, indicates Frédéric Calon. “In the end, it’s not such a dangerous drug. »
However, another factor weighs in the balance: the price of the drug, which amounts to US$26,500 per patient, per year, or about CAN$35,000.
Not to mention the close medical monitoring by imaging, which must be exercised to prevent the most serious effects. “All of this represents enormous costs, which will have to be partially reimbursed,” notes the researcher. That’s a lot of government money that goes to pay for drugs and that doesn’t go to research. Frédéric Calon and Étienne Aumont hope that we will succeed in negotiating the price of the drug downwards, with a view to its eventual approval by Health Canada.
And Canada, in all this?
In light of the results of the Clarity AD study, the FDA approved lecanemab in January, under an accelerated procedure. Domestically, the drug is under review, Health Canada confirmed last May. At this time, the public agency cannot comment on its status or provide a timeline.
“In my opinion, Health Canada will have to approve it, because there are still studies that demonstrate its effectiveness in terms of cognition,” notes Frédéric Calon. The Alzheimer Society of Ontario welcomed the FDA’s approval of Leqembi on Thursday.
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