In 2023, the U.S. Food and Drug Administration an Alzheimer’s therapy shown in clinical trials to modestly slow disease progression but side effects, brain swelling and bleeding, occurred in some.

Though clinical trials have taken twice as long and cost twice as much due to government regulations, they can't  cover everything and a successful doesn't mean broader demographics won't show different effects. Lawyers are gleeful at the opportunity to sue but they will be disappointed in the latest results for lecanemab. Adverse events associated with lecanemab treatment in clinic patients were rare and manageable.

Lecanemab, an antibody therapy, clears amyloid plaque proteins and was found to extend independent living by 10 months. Amyloid accumulation is the considered the first step in the disease, doctors recommend the drug for people in the early stage of Alzheimer’s, with very mild or mild symptoms. The researchers found that only 1.8% of patients with very mild Alzheimer’s symptoms developed any adverse symptoms from treatment compared with 27% of patients with mild Alzheimer’s. And only 1% of patients 234 patients with very mild or mild Alzheimer’s disease who received lecanemab infusions in the Memory Diagnostic Center at Washington University School of Medicine experienced severe side effects that required hospitalization. Patients in the earliest stage of Alzheimer’s with very mild symptoms experienced the lowest risk of complications.



That's good news for those concerned about a side effect known as amyloid-related imaging abnormalities, or ARIA. The abnormalities, which typically only affect a very small area of the brain, appear on brain scans and indicate swelling or bleeding. In clinical trials of lecanemab, 12.6% of participants experienced ARIA and most cases were asymptomatic and resolved without intervention. A small percentage — approximately 2.8% of participants treated — experienced symptoms such as headaches, confusion, nausea and dizziness. Occasional deaths have been linked to lecanemab in an estimated 0.2% of patients treated.

“This new class of medications for early symptomatic Alzheimer’s is the only approved treatment that influences disease progression,” said Barbara Joy Snider, MD, PhD, professor of neurology and co-senior author on the study. “But fear surrounding the drug’s potential side effects can lead to treatment delays. Our study shows that WashU Medicine’s outpatient clinic has the infrastructure and expertise to safely administer and care for patients on lecanemab, including the few who may experience severe side effects, leading the way for more clinics to safely administer the drug to patients.”