Lecanemab: The Hopes, Hype, and Truths About the New Alzheimer’s Drug
- Linda Andersen
- 2 days ago
- 7 min read
I've been asked several times in the past few weeks about the new Alzheimer's drug Lecanemab (marketed under the name Leqembi). It's obviously on peoples' minds, with questions like:
What's the hype all about and why is it getting so much attention?
Is this drug suitable for my friend or parent?
Does it actually cure Alzheimer's?
Is it safe?
How much does it cost?
These are some important questions, so I'll sum things up for you.
Lecanemab is the first Alzheimer's drug approved by Health Canada that targets
what scientists think is the cause of the disease:
Amyloid-beta protein
Amyloid-beta is a sticky protein that forms clumps (plaque) in the brain, causes an inflammatory cascade which damages brain cells and eventually leads to dementia. Scientists hope that targeting this protein at a stage during it's early formation and clearing it from the brain will slow the progression of the disease. With conditional approval from Health Canada in October of this year, Lecanemab is not yet available for general use in Canada (it could take over a year for it to become available through private drug plans and more than two years through public plans), but it is in several other countries including the United States, Japan, China and the UK.
Donanemab and Aducanumab are similar drugs, also targeting the amyloid protein in hopes of clearing it, but at a later stage when the plaque is more fully formed. Donanemab is currently only in pre-clinical trials and not yet approved by Health Canada. Aducanumab was withdrawn from Health Canada review because data wasn't sufficient to support marketing authorization. Canadian experts also had concerns about the drug's uncertain benefits and significant risks, including brain swelling and microhemorrhages (amyloid-related imaging abnormalities).
(By the way, the 'mab' suffix on these drugs stands for monoclonal antibody, meaning that the drugs are antibodies directed toward the target (amyloid), generating an immune response to destroy the protein.)
Unlike Lecanemab and Donanemab, most of the other Alzheimer's drugs have been focused on treating the symptoms. They enhance cognitive performance by upregulating (increasing the numbers of) certain neurotransmitters help to improve memory and cognitive function - but only temporarily - and have no effect on clearing the amyloid protein. Thus, the disease continues to progress in the presence of these drugs, and it's still only a matter of time before the patient succumbs.
Who is Lecanemab suitable for?
Because the drug specifically targets the early formation of amyloid protein – the hallmark of Alzheimer's disease – it is only suitable for people in the earliest stages of Alzheimer's with confirmed presence of amyloid protein. Some people may not display obvious symptoms of the disease but still show evidence of the protein on brain scans because amyloid can begin to build up decades before it's symptomatic. Unfortunately, by the time a lot of people receive a formal diagnosis, they may no longer be good candidates for this medication due to the advanced build-up.
Patients with other types of dementia such as vascular, Lewy Body or frontotemporal dementias (i.e. the types that are not characterized by amyloid plaque formation) are not eligible for treatment. Additionally, because of the high risk of brain swelling and micro-hemorrhages identified in early clinical trials, those people with specific conditions like stroke, brain bleeding or seizure disorders should not be prescribed. In line with this, people who carry the APOE4 gene are excluded from treatment because of the even higher risk of brain swelling and/or micro-hemorrhages in this population.
Does Lecanemab cure Alzheimer's?
Clinical trial results report that in people with mild cognitive impairment due to Alzheimer's disease (AD) or early stage AD, it can help slow the progression of symptoms such as declining memory, thinking and daily activities. After 4 years in trials, most of the participants are showing slower progression than normal. This is causing considerable excitement and the Canadian public is of course eager to know when it's going to be generally available.
However, it's important to note that this medication is not a cure and
cannot reverse the progression of Alzheimer's disease.
Is Lecanemab safe for people with early-stage AD?
Health Canada's authorization for its commercial use comes only with a careful and rigorous process to assess safety, efficacy and tolerability. However, as with any drug, there are potentially serious side effects and other considerable limitations and challenges.
The primary concern is Amyloid-Related Imaging Abnormalities (ARIA), which are serious adverse events reported during clinical trials involving swelling in the brain and micro- or macro-hemorrhages. People carrying the APOE4 gene are at even greater risk for these adverse events.
Treatment with Lecanemab requires regular MRIs to monitor for the presence of ARIAs. Therefore, patients with certain MRI contraindications may need to avoid Lecanemab.
The drug is administered via infusions every 2 weeks over 18 months, so there is always a risk of infusion-related reactions.
Because of the increased risk of brain bleeding (micro-hemorrhages), the drug's label warns against people taking blood thinners while on Lecanemab.
These considerations make it impractical for the majority of AD patients to prescribed the drug.
Despite Health Canada's authorization for commercial use and the overwhelming positive press it's been getting, I would be remiss if I didn't point out a few other issues. In a Phase 3 clinical trial, the drug slowed down the cognitive decline in patients with early-stage Alzheimer's by 27% over 18 months compared to a placebo. This percentage may sound pretty significant, but some critics argue this translated to only a "small" or "marginal" difference on an 18-point clinical scale (a 0.45-point difference), which may not be clinically meaningful or noticeable enough to allow patients to stay independent for a significant amount of time. Other critics question the value of the benefits in light of the significant risks.
In the early stages of Alzheimer's, many patients are still independent, so one should consider whether these significant risks are really worth it.
Additionally, if the problem of too much amyloid begins years or decades before people become symptomatic, it may be difficult to prescribe the drug at the correct time point.
What about the cost?
Currently, the drug is not covered under any Canadian public drug plan. Lecanemab was approved by Health Canada on October 25, 2025, but could still take over a year to become commercially available through private drug plans and more than 2 years through public plans.
Recently, the Canadian Press reported that the total annual costs for the treatment can run up to $26,000 US a year in other countries. Although commercial availability of Lecanemab is still several years away in Canada, it's estimated that the annual cost of treatment would be in excess of $35,000.
Over and above the cost of the vials of drug, another challenge is the fact that the drug is administered intravenously, which requires safety monitoring through regular MRIs. In addition to the significant expense of this type of imaging, these scans are typically hard to access outside of Canada’s large urban centers, creating a barrier to treatment in smaller centers.
Further Considerations
Something I've been pondering for quite some time is that amyloid protein likely isn't the sole cause of Alzheimer's, even though that's where the majority of AD funding is being allocated. Researchers have found that high amounts of amyloid are present in healthy aging brains as well as in individuals with Alzheimer's. The thing is, in the correct configuration and amount, this protein is actually beneficial and even protective in the brain, but when it aggregates and misfolds over time and is not cleared properly, it becomes toxic. In that case, maybe it's really a clearance problem, not an aggregation problem.
Then there's the question of why some people are not affected by high levels of amyloid in their brain.
This suggests that there are other proteins, perhaps related to faulty clearance of amyloid in the brains of AD patients, that could be targeted in conjunction with amyloid.
Some researchers suggest it's a matter of resilience because the buildup of amyloid alone is not always enough to cause dementia, and other factors like genetics and brain injury play a crucial role. They go on to suggest that the amyloid may be more toxic when combined with other markers of brain injury, suggesting that amyloid's toxicity is likely amplified by other pathological processes.
The bottom line
Lecanemab is a promising new drug for slowing the progression of Alzheimer's disease, but there are significant risks and cost.
So here's an idea: DON'T WAIT UNTIL YOU NEED MEDICATION!
According to the World Alzheimer Report 2024 by Alzheimer's Disease International, when people were asked if they would pursue a dementia diagnosis if they knew a drug was available that could modify the disease, over 90 per cent of respondents said they would.
But what if they were asked:
If you had prescribed access to an intensive lifestyle program that could reduce your risk of Alzheimer's and other dementias by up to 45%, would you do it?
We already know that this is the percentage risk reduction with certain lifestyle changes.
Unfortunately, when it comes to dementia our healthcare system is still focused on treatment rather than prevention. Insurance doesn't cover the cost of lifestyle interventions that are so much more than "moderately" effective for brain health. What if clinicians could be prescribing nutritional and exercise counseling, programs for stress reduction, and activities that engage the brain (cognitive exercises) and rest the brain (meditative practices)?
Occupational therapists can prescribe movement and exercise (and one I know even prescribes Forest Bathing), but only after an injury. This should be available for anyone at risk of dementia before it becomes untreatable.
We need forward-thinking policy makers to make some serious upgrades to the healthcare system that incorporate lifestyle strategies with proven high efficacy for dementia prevention rather than symptom relief.
Additional References and Further Reading
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