Memory Disorders Division

The main side effects of donanemab are swelling and bleeding in the brain discovered on a brain MRI, collectively known as amyloid related imaging abnormalities (ARIA). ARIA occurred in 37% of trial participants receiving donanemab, although most ARIA did not cause symptoms. Symptoms due to ARIA developed in 6% of trial participants treated with donanemab. Serious symptoms of ARIA occurred in 1.6% of people on donanemab. ARIA was more common in people with the e4 variant of the APOE gene.

Donanemab joins lecanemab (Leqembi) as the 2nd FDA-approved anti-amyloid antibody treatment approved for Alzheimer disease in the past year. Although the medications have a similar mechanism of action, there are advantages and disadvantages to each.

The Mass General Brigham Alzheimer Therapeutic Program (ATP) is enthusiastic about the FDA approval of donanemab and is seeking to add this medication to the Mass General Brigham hospital formularies as quickly as possible in our preparations to deliver the medication. Like all new medications, donanemab will be carefully reviewed by the Mass General Brigham Pharmacy and Therapeutics Committee, a process which can take weeks to month. If/when donanemab is approved by this committee, members of the ATP will work with eligible patients to discuss the pros and cons of treatment with lecanamab vs donanemab. 

We continue to accept new referrals to determine eligibility for anti-amyloid therapies and to initiate and oversee treatment with them.

The FDA has set guidelines on who will be eligible to receive this treatment, summarized in the FDA label. Only individuals who meet these guidelines will be evaluated to receive it, for safety reasons some individuals will be ineligible to receive this treatment. Experts in the field have also published an article documenting appropriate use recommendations.

Some patients and families may decide they do not want to receive this medication. We will support you by answering your questions, providing medical expertise and guidance as you weigh this new medication option.

The Centers for Medicare and Medicaid Services (CMS) has indicated that coverage will be provided to Medicare beneficiaries if enrolled in an approved Alzheimer Patient Registry. The medication costs approximately $26,500 a year. The exact cost to beneficiaries is not yet known and will vary by different insurance coverage plans. For example, individuals with Original Medicare will pay the standard 20% coinsurance of the Medicare-approved amount for lecanemab once they meet their Part B deductible, whereas patients with supplemental Medicare plans may have much of this deductible covered. Patients may also be responsible for some costs associated with infusions, MRI scans, health care provider appointments, and other aspects of treatment. Some private health insurance plans have announced plans to cover lecanemab with prior authorization, whereas other plans have not yet provided details.

Patient registries will collect information from providers to help ensure appropriate patient selection and use of anti-amyloid antibody treatments for AD. Data about patient outcomes and safety will be of critical importance and will help us make decisions about future treatment options.

On August 22, 2023 the MGB Pharmacy & Therapeutics Committee approved lecanemab for addition to the MGB formulary. With this approval, the Mass General Brigham Alzheimer Therapeutic Program (ATP) is working to complete the remaining steps required to deliver lecanemab to established patients within the Mass General Brigham system. We expect to be able initiate treatments this fall. Mass General Brigham physicians will be instructed on how to refer appropriate patients to the ATP to determine their eligibility and, if appropriate, to proceed with treatment. The ATP will be responsible for monitoring MGB patients on lecanemab.

Please check back on our websites for updates on when lecanemab will be available.
Memory Disorders Unit at MGH
Center for Brain/Mind Medicine at BWH

To be considered for treatment, you must be evaluated for cognitive changes and receive a diagnosis of mild cognitive impairment due to AD or mild AD dementia The following elements must be completed by your primary care doctor, neurologist, psychiatrist, or other referring provider prior to referral:
- Brief cognitive evaluation within 6 months of referral.
- MRI of brain within 12 months of referral
- Basic lab tests within 6 months of referral
- Confirmation that you do not take a full-strength anticoagulation (blood-thinner) medication and/or any medication that suppresses the immune system on a chronic basis.
- Confirmation that you do not have a poorly controlled medical, neurological, or psychiatric condition in addition to AD.
- In addition, the following testing will be necessary to determine eligibility; these can be done either before referral or within the ATP:

1. A test confirming that you have elevated brain amyloid, to be completed either prior to referral or after referral. Tests of cerebrospinal fluid (CSF; obtained by lumbar puncture) or amyloid positron emission tomography (PET) imaging may be used for this purpose. CMS currently does not cover amyloid PET, but this policy could change.
2. A test to determine what versions of the APOE gene you carry. This information is needed for understanding what your risk of side effects would be if you were to receive lecanemab.

Lecanemab is given every 2 weeks by a healthcare provider through a needle placed in your vein (intravenous (IV) infusion) in your arm. Each infusion will last about 1 hour. The Mass General Brigham ATP will be responsible for providing your schedule of infusions. Infusions will be given at Mass General Brigham hospitals and satellite facilities. This infrastructure is currently being developed. Arrangements have not yet been made to accommodate patients who reside part time in a different state, which will require coordination with other facilities providing treatment with lecanemab.

Lecanemab is currently given every two weeks, for a minimum of 18 months. Additional information is being collected on the treatment period to guide decision making once these 18 months are completed. In addition to infusion visits and regularly scheduled visits with their referring providers, patients receiving lecanemab in the ATP will be seen in the ATP clinic every 6 months (or more often, as indicated) and will have safety MRIs completed 2 months, 3 months, and 6.5 months into treatment (plus additional MRIs as indicated).

Lecanemab can cause small areas of swelling or bleeding in the brain called amyloid related imaging abnormalities (ARIA). ARIA is usually asymptomatic and detected only by monitoring MRI scans. In the phase III study investigating lecanemab, only 2.8% of subjects receiving lecanemab had symptoms due to ARIA. Most symptoms were mild, involving temporary symptoms including headache, confusion, dizziness, changes in vision, nausea, or difficulty walking, and were temporary. However, ARIA-related swelling occurred in 12.6% of subjects receiving lecanemab, and 8.4% of subjects had both swelling and bleeding, often without producing symptoms. Patients will therefore need to be monitored with serial MRIs (usually monthly) until it resolves (usually within 6 months).

Rarely, ARIA can cause seizures or larger areas of inflammation and/or bleeding in the brain. The risks of ARIA, symptomatic ARIA, and serious symptomatic ARIA leading to hospitalization are highest in people carrying 2 copies of the APOE ε4 gene. In the phase 3 study, the rates of symptomatic ARIA with lecanemab treatment were 9.2% in participants with 2 APOEε4 genes, 1.7% in participants with 1 APOE4 gene, and 1.4% in participants who did not carry an APOE4 gene. The rates of serious symptomatic ARIA were 2.1% in participants with 2 APOE4 genes, 0.4% in participants with 1 APOE4 gene, and 0.7% in participants who did not carry an APOE4 gene.

In the first part of the lecanemab phase 3 trial where 1795 participants received either active drug (lecanemab, 898 participants) or placebo (salt water, 897 participants) over 18 months, there was no difference in the number of participants who died (6 receiving lecanamb and 7 receiving placebo). Following this part, participants were offered to continue in an extension (open label portion) of the study where everybody received active drug (lecanemab) and nobody received placebo (salt water). During this extension, 3 participants (out of about 900) died from side effects thought to be due to lecanemab Two of the deaths were related to brain hemorrhages (bleeding), one occurring in a participant on anticoagulation (a blood thinner), the other in a patient who received tissue plasminogen activator, a medication used to break down blood clots in patients with acute stroke. The third death occurred in a patient homozygous for APOE4 (with 2 copies of the APOE4 gene) who developed swelling and bleeding in the brain similar to a condition involving excessive amyloid protein in blood vessels in the brain with associated inflammation. Under the ATP protocol, patients on anticoagulation will not be eligible to receive lecanemab. A key purpose of the screening MRI prior to treatment is to identify findings such as small areas of bleeding (microhemorrhages) and other features suggesting amyloid protein in blood vessels that would lead to a higher risk of serious ARIA. Also, all patients will have APOE genotyping prior to deciding about treatment with lecanemab. This will allow us to identify patients with 2 copies of the APOE4 gene, who are at higher risk for developing side-effects.

Donanemab is another anti-amyloid antibody recently investigated in a phase 3 clinical trial, with results suggesting it slows cognitive and functional decline in MCI due to AD and mild AD dementia. The results were recently published in the Journal of the American Medical Association. Because this study was completed more recently, the submission for full FDA approval of donanemab has yet to be reviewed by the FDA.

Aducanumab was studied in two phase 3 studies, that, for various reasons did not provide sufficient data to definitively determine its effectiveness for slowing symptoms of AD. It was granted accelerated approval from the FDA (rather than full approval) and is NOT covered by Medicare. Aducanumab is currently being investigated in a Phase 3b/4 study conducted at numerous sites including the BWH Center for Alzheimer Research and Treatment.

While the phase 3 study provided a preliminary analysis of selected subgroups of subjects with AD, it was not designed or powered to provide conclusive results about the effectiveness or side effects of lecanemab in these subgroups. Additional data from more subjects will be helpful to answer these important questions. This is one purpose of the registry noted above.

Deciding to start treatment is a decision you should make with your family, and your physician. We will continue to be a resource for you if you decide not to receive treatment. We will review options with you and your physician, such as research, and supportive care.
Watch: Hope & Empowerment Through Research

Prior participation in clinical therapeutic research studies will not make you ineligible to receive lecanemab, provided the other eligibility criteria are satisfied.

At present, most if not all clinical therapeutic studies investigating potential new treatments for AD do not allow concomitant treatment with lecanemab. This could change in the future. We recommend speaking with your current provider and/or contacting us at the Center for Alzheimer Research and Treatment if you have questions about whether pursuing treatment with lecanemab or enrolling in a clinical therapeutic research study is the best option for you.

If you are currently enrolled in a clinical therapeutic study or an observational study, please contact your research site about the potential impact of pursuing treatment with lecanemab on your ongoing participation in the study.