MAKING SENSE OF NEW ALZHEIMER'S DRUGS

 

Monoclonal antibody drugs for Alzheimer’s disease are making headlines—but what do they really mean for patients and families? At Functional Pharmacy, we help you cut through the hype and clearly understand the potential benefits, risks, and costs so you can make confident, informed decisions about your care.

 

 

 

 

 

Comparing New Treatment to Standard of Care

The figure plots the change on the ADAS‑Cog (0–90 scale; higher = worse) for two cognitive interventions versus placebo — donepezil (a standard symptomatic therapy) and lecanemab (an anti-amyloid disease‑modifying monoclonal antibody). The Y-axis scale is identical for both to enable direct visual comparison [Figure 1 from Espay et al.’s “Lecanemab and Donanemab as Therapies for Alzheimer’s Disease: An Illustrated Perspective on the Data']

What the studies show:

 

With both Aricept and the newer antibody treatments, people’s memory and thinking still decline over time. In studies of lecanemab and donanemab (the new antibodies), after about 18 months of treatment, the benefit compared to placebo was smaller than the benefit Aricept showed after just 6 months. Importantly, in all groups (whether on drug or placebo), memory and thinking got worse during the study. 

 

 

The hope with antibodies:

 

Some experts believe that if people keep taking antibodies longer, the difference between treatment and placebo might get bigger with time. However, this has not yet been proven. For Aricept, when people were followed longer, that extra benefit did not continue to grow.

 

 

Bottom line for now:

 

Both Aricept and the antibodies may slow decline a little, but neither stops Alzheimer’s from progressing. Aricept is simple, inexpensive (just a few dollars a month with generics), and has been studied for over 20 years. It can provide a modest and temporary improvement in memory and daily function, but the benefit fades over time. The new antibody drugs, lecanemab and donanemab, are far more costly (about $26,000–$32,000 per year plus infusion and monitoring costs), require regular IV treatments and brain scans, and carry higher risks such as brain swelling or bleeding. Their benefit so far is small, and it is still uncertain whether they will make a meaningful long-term difference.

 

 

 

 

 

 

Overview of Monoclonal Antibodies in Dementia

What the studies show

 

Lecanemab (Leqembi) and Donanemab (Kisunla) are two Alzheimer’s antibody drugs that slow memory and daily function decline by about one-third in people with mild disease and lower levels of brain changes. But when you look closely, the difference was very small. After about a year and a half, people on donanemab scored only 3 points better (out of 144) compared to placebo.

 

The results from the lecanemab study were similar, with the difference in cognitive decline amounting to about half the change you would expect from using donepezil. Doctors agree that such a small change is something patients, families, and even physicians would not actually notice in daily life.

 

 

 

 

On safety

 

The bigger issue is side effects. These drugs are not very safe:

 

  • With lecanemab, almost half of patients had problems from the drug, and about 1 in 4 developed brain swelling or bleeding. Some of these cases were severe, and a few were fatal. 
  • With donanemab, almost 9 out of 10 patients had side effects, and over 1 in 3 had brain swelling or bleeding. 
  • Brain swelling can actually speed up brain shrinkage, which is already a problem in Alzheimer’s disease. 

 

 

 

Numbers that matter

 

Doctors sometimes use two numbers to weigh benefits and harms:

 

  • Number Needed to Harm (NNH): For these drugs, for about every 3 patients treated, 1 will have a harmful side effect.
  • Number Needed to Treat (NNT): How many patients need the drug for 1 to benefit. With these antibody drugs, we don’t yet know this number—because the studies haven’t shown a clear, meaningful benefit at the individual level. 

 

 
Bottom line & FINAL THOUGHTS

 

These new antibody drugs do not improve memory or thinking. They only slightly slow decline, and the benefit is so small that most patients and families would not notice. The risks, however, are significant—especially brain swelling, bleeding, and even death. Aricept (donepezil), the older pill, may be safer and at least as effective in the short term, even if its benefits are modest and temporary.

 

Drug companies are continuing to test these treatments in people at earlier stages of Alzheimer’s, sometimes paired with lifestyle changes. But right now, the benefits are small, the risks are high, and the cost (about $25,000 per year) would strain patients and the healthcare system if many people started using them.