New Alzheimer ’ s drug stirs hope and scepticism
The benefits are modest and more data are needed
There ’ s a lot of buzz around an experimental medication that has slowed cognitive decline by 27 percent in patients with early Alzheimer ’ s disease , according to data released by the pharmaceutical companies that developed it .
Alzheimer ’ s Research UK research director Dr Susan Kohlhaas told the BBC this was a breakthrough and a “ historic moment for dementia research ” as it was the first large clinical trial “ in a generation ” to improve cognitive decline , a condition that ’ s a growing health problem worldwide . It ’ s also known as dementia , an umbrella term that comprises several forms of mental decline , including Alzheimer ’ s .
Developed by Eisai and Biogen , the drug lecanemab led to improvements in the CDR-SB score , which quantifies symptom severity in dementia , in a clinical trial involving 1,795 participants who either received the drug or a placebo , a dummy pill . It also managed to decrease the amounts of the protein amyloid in the patients ’ brains , a key hallmark of Alzheimer ’ s that can be diagnosed with imaging technology . But some experts sounded a note of caution . Though the results are “ quite promising […] we ’ ll have to see what the full analysis of the trial suggests ,” Dr Caleb Alexander , an internal medicine specialist and epidemiologist at the Johns Hopkins Bloomberg School of Public Health in the US , told Nature .
He also noted that the clinical benefit provided by lecanemab is small .
The drug was developed to clear amyloid plaques in patients with Alzheimer ’ s , based on the theory that accumulation of the protein has a toxic effect on brain cells that eventually cause dementia .
However , this theory , known as the amyloid hypothesis , has been called into question by several experts who point out that there are many elderly people with amyloid plaques who never develop Alzheimer ’ s .
Amyloid is “ associated with the problem , but it isn ’ t ‘ the ’ problem ”, Dr George Perry , a neurobiologist at the University of Texas at San Antonio and a sceptic of the amyloid hypothesis , told Nature . “ If you modulate it , of course you can have some small benefit .”
A similar drug , Aducanumab , which can reduce amyloid in the brain , was approved by the US Food and Drug Administration last year but has sparked controversy among experts because its benefits are modest while the results observed in clinical trials were mixed . An early analysis showed the drug offered no significant improvement while a subsequent one suggested it could slow the loss of cognitive abilities , though such benefits aren ’ t clear-cut . This prompted the FDA to request additional post-approval trials to verify the new drug ’ s efficacy in helping patients .
“ Aducanumab stands out as a remarkably unique case of poor decision making using very complicated and noisy data ,” Dr Jason Karlawish , the co-director of the Penn Memory Center at the University of Pennsylvania , told Global Health Asia-Pacific .
Though Dr Karlawish believes Aducanumab will “ fade into history ,” other drugs that clear amyloid plaques from the brain are being tested and could still prove to be beneficial to patients with Alzheimer ’ s .
The hope is that lecanemab will be one of them .
There are many elderly people with amyloid plaques who never develop Alzheimer ’ s .
GlobalHealthAsiaPacific . com ISSUE 5 | 2022
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