UW Medicine offers second drug for early Alzheimer’s

UW Medicine’s Memory & Brain Wellness Center at Harborview Medical Center in Seattle recently started treating patients with donanemab, an Alzheimer’s drug. The drug is similar to lecanemab, which the center began offering in late 2023.

[Download broadcast-ready soundbites and multimedia about donanemab therapy at Harborview Medical Center.]

The drugs cannot cure Alzheimer’s or reverse memory loss. They have been shown to slow the rate of cognitive decline in patients with mild impairment or mild dementia due to Alzheimer’s disease, said Dr. Thomas Grabowski, professor of radiology and neurology at the University of Washington School of Medicine. He is medical director of the Memory and Brain Wellness Center.

“While we don’t know whether donanemab or lecanemab can arrest Alzheimer’s, they do appear to help people with mild cognitive impairment and extend the time they are independent and able to manage their daily lives,” Grabowski said.

Both drugs are monoclonal antibodies that bind to proteins called amyloid-beta. These proteins form insoluble clumps in the brain, amyloid plaques, which contribute to the brain damage that leads to dementia seen in Alzheimer’s disease. By binding to the proteins, the drugs’ antibodies stimulate the patient’s immune cells to clear amyloid from the brain.

Both drugs are given intravenously, but donanemab is administered once a month, versus every two weeks for lecanemab.

“For people coming to us for treatment from Eastern Washington, Montana, Idaho and the Olympic Peninsula, that donanemab has to be give only once a month is a big advantage,” said Dr. Michael Rosenbloom, associate professor of neurology at the UW School of Medicine and clinical trials director at the Memory and Brain Wellness Center.

Another advantage: Clinical trials showed that donanemab’s benefits were present even when the drug was stopped, once the amyloid plaques were cleared, potentially shortening the length of treatment, Rosenbloom said.

To qualify for treatment, a patient must have early symptoms of Alzheimer’s disease, such as mild cognitive impairment and mild dementia, and evidence of amyloid plaques. Evidence of amyloid can be determined with special brain-imaging studies or tests of cerebral spinal fluid or blood.

The most common side effect of treatment with either drug is leakage of fluid from blood vessels in the brain. This leakage can cause either localized brain swelling or microhemorrhages. These effects often cause no symptoms but can be seen on magnetic resonance imaging (MRI), so they are called amyloid-related imaging abnormalities (ARIA).

All patients are routinely screened for ARIA with periodic MRIs as part of the treatment. If ARIA is detected, the treatment is stopped until the MRI scans return to normal. However, if patients experience major neurological symptoms or have extensive ARIA throughout the brain, the drug will likely be halted.

People who carry one or two copies of a gene called ApoE epsilon 4 have a higher risk of developing ARIA with donanemab. Anyone considering donanemab will be screened for these genes to assess their risk. Someone who carries two copies of the gene might consider choosing lecanemab, Rosenbloom said.

Because the treatment has only been found to be effective among patients with mild cognitive impairment or mild dementia due to Alzheimer’s, it is important for people who experience cognitive problems to consult their primary-care providers for evaluation. If their cognitive problems stem from Alzheimer’s, the medications may be started early, when they are most likely to have benefit, Rosenbloom said.

Medicare covers treatment with both drugs. Private insurance coverage will depend on the provider and plan. Interested patients and family members should speak with their primary-care provider or neurologist. 

Written by Michael McCarthy. 

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