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New Drug May Help Slow Effects of Alzheimer’s for Those with Mild Symptoms

Statistics about Alzheimer’s disease are sobering. According to the Alzheimer’s Association, one in nine Americans ages 65 and older have Alzheimer’s disease, amounting in 2023 to 6.7 million people. So it's no wonder that many paid attention when the Food and Drug Administration (FDA) announced its approval of a new drug called lecanemab in January 2023.  

To date, lecanemab is the first traditional approval of a treatment for Alzheimer’s disease. Its predecessor, aducanumab, received accelerated approval from the FDA but has not been approved for use outside of participation in clinical research by the Centers for Medicare and Medicaid Services (CMS) . 

Registered as Leqembi® by Eisai R&D Management Co., Ltd., the drug shows great promise. “It's by no means a silver bullet,” warns Michelle Sorweid, DO, MPH, medical director of the Aging Brain Care Program in the Division of Geriatrics at University of Utah Health. "We have a long way to go in the field, but we hope it is a step in the right direction.” 

What does the approval of lecanemab mean for patients who are diagnosed with Alzheimer’s?

Lecanemab holds promise for patients in early stages of the disease. The drug slows progression of Alzheimer’s, giving people more time to live independently and participate in daily activities. Lecanemab does not reverse or stop the disease, nor does it restore lost memories or cognitive function. 

How does lecanemab work?

Lecanemab is a monoclonal antibody infusion given every two weeks to clear amyloid plaque proteins from the brain, Sorweid explains. Amyloid plaques are proteins that are found in the brains of individuals with Alzheimer's disease. These proteins have misbehaved, deposited in the brain, and caused nerve cell death or dysfunction. According to Sorweid, this is just one of the causes of Alzheimer's disease, which is why this medication and others in its class are not a cure. 

Who is a candidate for lecanemab?

The drug is for those who have mild Alzheimer’s disease, which means mild cognitive impairment or mild dementia. These patients are still independent in most daily activities and don’t need help with daily tasks like bathing, going to the bathroom, and eating. Sorweid says that those individuals also meet certain memory assessment screen scores above a specific cutoff.  

What are the side effects of lecanemab?

According to the study results, patients using lecanemab did not have as much cognitive and functional decline as those on the placebo. However, there were some associated adverse reactions. 

Sorweid says some of these side effects include: 

  • Infusion reaction 
  • Headache 
  • Dizziness 
  • Confusion 

A side effect unique to the anti-amyloid class of drugs is ARIA (Amyloid Related Imaging Abnormalities), microhemorrhages or edema (small areas of swelling) on brain MRIs used in clinical trials for all patients. Most of these ARIA were asymptomatic and occurred in about 12% of patients. Only about 3% were symptomatic. 80% of patients who showed they had ARIA also experienced resolution of these symptoms by the end of the trial.  

Researchers suggest longer trials are needed to determine the efficacy and safety of lecanemab in early Alzheimer’s disease. 

What can patients do who are interested in taking lecanemab?

For those who have a diagnosis of mild cognitive impairment or mild dementia due to Alzheimer’s disease, ask your primary care provider for a memory screening assessment.  Those with mild symptoms who are not on certain blood thinner medications may benefit from an evaluation by a dementia specialist in their area.