Canada Approves Leqembi Alzheimer’s Drug

On October 25, 2025, Health Canada granted conditional authorization for lecanemab, marketed as Leqembi, marking the first disease-modifying therapy approved in the country for early-stage Alzheimer’s disease. This long-awaited approval offers hope to patients with mild cognitive impairment (MCI) or mild dementia due to Alzheimer’s, provided they have confirmed amyloid pathology and are apolipoprotein E ε4 (ApoE ε4) non-carriers or heterozygotes. Unlike symptomatic treatments that only manage symptoms, lecanemab targets an underlying cause by reducing amyloid-beta plaques in the brain, potentially extending quality time for patients and families.

How Lecanemab Works

Lecanemab is a humanized monoclonal antibody developed by Eisai Co., Ltd., and Biogen Inc. It binds to soluble amyloid-beta protofibrils and insoluble fibrils, helping to neutralize and clear these toxic proteins from the brain. Amyloid plaques are hallmark features of Alzheimer’s, contributing to neuronal damage and cognitive decline. By addressing this buildup early, the drug aims to slow disease progression rather than reverse it.

Clinical Evidence and Efficacy

The approval is based on the global Phase 3 Clarity AD trial, involving over 1,700 participants with early Alzheimer’s. Over 18 months, lecanemab reduced cognitive decline by 27% on the Clinical Dementia Rating-Sum of Boxes (CDR-SB) scale compared to placebo (adjusted mean change: 1.21 vs. 1.66; difference -0.45). It also improved daily functioning by 37% on the Alzheimer’s Disease Cooperative Study-Mild Cognitive Impairment-Activities of Daily Living (ADCS-MCI-ADL) scale. Longer-term data from extensions and open-label studies show sustained benefits, with a -0.95 reduction in CDR-SB decline over three years.

Real-world outcomes from early adopters in other countries, such as a 2025 study in a tertiary hospital, confirm its feasibility and safety, with ongoing monitoring needed to assess long-term effects. However, some experts note that the cognitive improvements, while statistically significant, may not always feel clinically meaningful to patients (e.g., a 0.45-point difference on an 18-point scale), underscoring the need for further research.

Administration, Eligibility, and Access

Lecanemab is administered intravenously every two weeks, typically in a clinic or hospital setting, and treatment may continue indefinitely based on patient response. Eligibility requires confirmation of amyloid buildup via PET scans or lumbar punctures, plus ApoE ε4 genetic testing to mitigate risks. It’s not suitable for those with two ApoE ε4 copies (homozygotes), advanced disease stages, or certain comorbidities like stroke or bleeding disorders.

In Canada, rollout could begin by late 2025, but access challenges remain. The Alzheimer Society of Canada urges provincial governments and the Canadian Drug Agency to expedite public funding and infrastructure, including specialized infusion centers and diagnostic tools. Private insurance may cover it sooner, but timelines for public plans could exceed two years. Eisai plans to submit real-world data to Health Canada to verify benefits and potentially remove conditional status.

Cost Considerations

Pricing in Canada has not been finalized, but in the U.S., a year’s supply costs approximately US$26,500 (about CAD$36,700 at current exchange rates). In Japan, it’s around US$20,500 annually. Without public funding, this could limit access for many Canadians. Advocacy groups emphasize equitable coverage to ensure all eligible patients benefit.

Potential Side Effects and Risks

While generally well-tolerated, lecanemab can cause amyloid-related imaging abnormalities (ARIA), including brain swelling (ARIA-E) in 12.6% of patients and micro-bleeding (ARIA-H) in 17.3%. These are often asymptomatic and detected via MRI, but symptoms like headaches, dizziness, or in rare cases, seizures or stroke-like events can occur. Fewer than 1% experience persistent effects after stopping treatment. Infusion reactions, headaches, and falls are other common issues.

Dr. Andrew Frank, a cognitive neurologist at the Bruyère Memory Program in Ottawa, explained that these effects stem from the drug’s action on amyloid, potentially causing inflammation. He supports access, noting patients should weigh benefits against risks with their doctors. Trial deaths were comparable (6 on lecanemab vs. 7 on placebo), but ongoing scrutiny is recommended, especially for those on blood thinners.

Patient and Advocacy Perspectives

Adam Morrison from the Alzheimer Society of Ontario highlighted the excitement among families, viewing lecanemab as a way to gain “more time” with loved ones. The Alzheimer Society of Canada echoes this, advocating for patient registries to track real-world outcomes and calling for investments in dementia care infrastructure. They stress that lecanemab is not a cure and should complement risk reduction strategies, early diagnosis, and support services.

Broader Context: Comparisons and Future Directions

Lecanemab joins a new class of anti-amyloid therapies. In the U.S., it’s approved alongside donanemab (Kisunla), which targets established plaques and is given monthly, potentially showing slightly stronger efficacy in some cognitive measures but with similar ARIA risks. Donanemab is not yet approved in Canada, but its review could follow. Both drugs represent progress after decades of setbacks, with lecanemab now available in about 50 countries since its 2023 U.S. approval.

Experts recommend consulting healthcare providers for personalized advice. As research evolves, including four-year data showing continued benefits, lecanemab could pave the way for combination therapies addressing multiple Alzheimer’s pathways. For now, this approval signals a pivotal shift in managing early Alzheimer’s in Canada.