A Promising New Drug for Alzheimer’s Disease

In January, the Food and Drug Administration (FDA) approved Leqembi (lecanemab) for the treatment of early-stage Alzheimer’s disease. While not an all-out game-changer, the new drug represents a new approach—one that is of real benefit to patients, says Dr. Matthew Fink, Neurologist in Chief and Louis and Gertrude Feil Professor and Chairman of the Department of Neurology at Weill Cornell Medicine. 

“For the past 20 years, there was nothing new to offer,” he says. “We’ve had two classes of medication for Alzheimer’s, both inadequate: donepezil (marketed as Aricept, among others), which changes neurotransmitters in the brain a little but has no effect on the underlying causes of the disease; and memantine (Namenda), which prevents the condition from getting worse—a little.” 

There’s a third drug, aducanumab (Aduhelm), that was withdrawn from the market less than a year after approval. Doctors and patients alike saw that the FDA had made a bad decision, based on a finding of improvement in the brain scans of Alzheimer’s patients. But it quickly became clear that Aduhelm had no clinical benefit.  

By contrast, “lecanemab, an antibody-based drug, actually removes some amyloid protein from the brain,” Dr. Fink says. “It’s the first medication that has been shown to slow the progression of the disease for real. It won’t make you better, but it will slow the decline associated with Alzheimer’s.” 

Who should consider taking lecanemab? 

If you have early-stage Alzheimer’s disease, and you’re in good health, lecanemab may be for you. Those with advanced Alzheimer’s are not appropriate candidates for the drug.  

Dr. Fink stresses one important caveat: If you’re on an anti-coagulant drug, you should carefully review the risks for bleeding with your doctors before you decide to take the new drug.  

Safety concerns 

Lecanemab binds to components of the amyloid proteins that are a major cause of the disease, triggering an inflammatory response in the brain, he explains. However, about 25 percent of the patients who participated in the recent clinical trial of the drug had significant swelling, seen on MRI brain scans. A smaller number experienced bleeding as well.  

Most of them didn’t have symptoms and did well on the drug. However, 3 patients died from a massive brain hemorrhage; 2 of the 3 were taking blood-thinning medications at the time of their deaths, upping their risk of a brain bleed. “That’s why we need to be especially careful to warn patients about the dangers of being on an anti-coagulant when taking lecanemab,” he says. 

Alzheimer’s disease FAQs 

How is Alzheimer’s disease different from regular aging? 

Many normal, healthy people worry they might have Alzheimer’s when they experience a few short-term memory issues, such as misplacing their keys or their cell phone or forgetting names. These are examples of normal aging, Dr. Fink says: “Short-term memory loss can actually begin at age 35! We all lose our keys, and that can happen at any age. But if you don’t know how to use your keys, that’s a different story, having to do with executive function: how you organize your day, carry out routine tasks and keep track of time.” 

How is Alzheimer’s diagnosed? 

In recent years, he says, the ability to diagnose Alzheimer’s has improved tremendously. Instead of relying on memory testing, an EEG (electroencephalogram) or traditional brain scans—none of which show changes associated with early-stage Alzheimer’s—doctors can now examine blood and spinal fluid for chemicals associated with the disease. These tests are accurate 90 percent of the time. Doctors also make use of a specific type of PET scan that measures beta amyloid proteins—the main culprit in Alzheimer’s—in the brain. That test is 90 percent accurate as well. 

Are Alzheimer’s and dementia the same thing? 

“Dementia is a general term denoting the loss of cognitive function. Alzheimer’s disease is one form of dementia. About 50 percent of the patients we see with dementia turn out to have Alzheimer’s,” Dr. Fink says.  

Lewy body dementia is the second-most prevalent cause of Alzheimer’s, followed by vascular disease of the brain. 

What can I do to avoid developing Alzheimer’s disease? 

“Even if you’ve heard some or all of these before, there’s strong evidence now that the Simple Seven works to prevent both cardiovascular disease and Alzheimer’s,” says Dr. Fink. In other words, there’s a lot you can do to take control of your present and future health—good news for individual patients and for the health of the nation.  

The new Alzheimer’s drug in perspective 

The fight against Alzheimer’s is far from over, he says. “A great deal of research is still needed. Effective treatment will require a combination of drugs with different mechanisms of action. We’re not there yet, but that’s what the future looks like.  

Lecanemab is a major step toward that future. It’s “a new approach that offers some real benefit to patients. It’s safe to predict that new, better treatments will be coming along. The new drug will stimulate scientists and pharmaceutical companies to step up their research efforts, building on the admittedly modest success of lecanemab.” 

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