Lecanemab is administered by intravenous infusion (injection) every two weeks, and patients in clinical trials underwent regular magnetic resonance imaging (MRI) to monitor effects in the brain and tests to monitor changes in thinking and function.
Results have been controversial. Lecanemab is not a cure, but clinical trials showed people treated with the drug had a 27% reduction in decline in amyloid over 18 months, compared to people who were given a placebo. People taking the drug had slower rates of decline, however this was modest and not generally clinically evident in people who were more affected by the disease.
Lecanemab had numerous side-effects. In one clinical trial involving 1,734 people1, around a quarter (26.4%) had localised reactions to the infusion of the drug. More seriously, abnormalities were found on MRI. Called amyloid-related imaging abnormalities or ‘ARIA’, researchers found 14.0% of people receiving the drug had brain microhaemorrhages, compared to 7.7% on placebo, and 12.6% of people taking the dug experienced oedema (brain swelling), compared with 1.7% taking a placebo.
These side-effects were often asymptomatic and for many mild; most settled spontaneously. However, for a few side-effects were serious including larger haemorrhages. People at greater risk for serious haemorrhages were those on anticoagulants (not aspirin) and those with a certain genetic profile, i.e. having two copies of apolipoprotein E e4
Despite approvals in USA, China, Japan, Korea, Israel and UK but not in European Union (EU), on October 16 2024, the Australian Therapeutic Goods Administration (TGA) declined to register Lecanemab for use in Mild Cognitive Impairment due to Alzheimer’s pathology or in early Alzheimer’s disease. They cited significant safety concerns about the drug that they considered outweighed potential benefits.
The sponsor of Lecanemab, Eisai Australia Pty. Ltd. is planning to appeal this decision.
Since then, the EU has amended its decision and is now approving Lecanemab except for people who have two copies of APOE e4. It remains unknown whether this will influence the TGA.
Another consideration is the cost of Lecanemab, about AUD$40,000 per year. If the TGA approves an application will still need to be made to the Pharmaceutical Benefits Advisory Committee which weighs up costs and benefits. In the UK, the National Institute for Clinical Excellence (NICE) did not approve subsidisation.
Many people in Australia will be bitterly disappointed as new drugs are accompanied by many expectations and hopes. There is however much that can be done to improve quality of life. We encourage you to use this website, Forward with Dementia, to explore proven therapies and strategies to come to terms with dementia and live well.
The medical journal, The Lancet, suggests that Lecanemab may be a starting point for more effective treatments to reduce dementia symptoms or delay progression. But they also suggest that the current focus for public health should be addressing modifiable risk factors for dementia. These include managing high blood pressure and diabetes, stopping smoking and keeping weight at healthy levels, addressing hearing loss and staying socially, cognitively and physically active to maintain brain health across the lifespan. You can read more about reducing your risk on the Face Dementia website.
The Dementia Australia Helpline can be contacted 24/7 on 1800 100 500.
1 van Dyck et al., (2022) Lecanemab in Early Alzheimer’s Disease. NEJM. Doi: 10.1056/NEJMoa2212948
For more information on this website
Other information on medications:
