Leqembi and Down Syndrome

This viewpoint reports on the results of the Clarity AD trial, a phase 3 randomized clinical trial of lecanemab for patients with early Alzheimer disease, in which lecanemab’s clinical efficacy was demonstrated using well-established outcome measures. Authors discuss the implications of the findings and the reported risks. From a clinician's perspective, they comment that persons diagnosed with Alzheimer's disease should have access to this drug, although no mention is made of its safety or applicability to adults with intellectual disability. The authors note the work that still remains to be undertaken, lecanemab's success represents a major milestone for the field, and what they consider as a moment of great hope for patients and families living with Alzheimer's disease.

Source: Wolk DA, Rabinovici GD, Dickerson BC. A Step Forward in the Fight Against Dementia-Are We There Yet? JAMA Neurol. 2023 Mar 13. doi: 10.1001/jamaneurol.2023.0123. Epub ahead of print. PMID: 36912845.

An Advisory and Consensus Statement of the Working Group on Criteria for Access to Alzheimer’s Therapeutics for Adults with Down Syndrome; experts were convened to determine prescribing criteria equivalences that would be inclusionary of adults with Down syndrome. This advisory and consensus statement is the result of the experts’ deliberations and recommendations for addressing this inequity to treatment access and includes alternative inclusionary language and modified criteria, as well as providing a roadmap for prescribers when determining eligibility for adults with Down syndrome.

The Food and Drug Administration on July 6, 2023 gave full approval to the Alzheimer’s drug Leqembi, and Medicare said it would cover much of its high cost, laying the foundation for widespread use of a medication that can modestly slow cognitive decline in the early stages of the disease but also carries significant safety risks. Leqembi will be available for people with mild dementia or a pre-Alzheimer’s condition called mild cognitive impairment. The F.D.A. label instructs doctors not to treat patients without testing to confirm they have an accumulation of the protein amyloid, a hallmark of Alzheimer’s that Leqembi attacks. The F.D.A. decision granting full approval to Leqembi means that Medicare will cover it for eligible patients. Some patients will be unable to afford the 20 percent Medicare does not cover, possibly about $6,600 a year. Including costs of medical visits and required regular brain scans, some of which will receive Medicare reimbursement, the treatment could run to about $90,000 a year. Doctors prescribing Leqembi will be required to submit medical information about each patient before and while they are being treated with the drug. The information will be kept in patient registries and evaluated to learn more about Leqembi’s benefits or harms.

Food and Drug Administration on January 7, 2023, approved another Alzheimer’s drug that may modestly slow the pace of cognitive decline early in the disease, but also carries risks of swelling and bleeding in the brain.

LuMind IDSC has noted that there remain substantial barriers to Leqembi being deemed safe and accessible for people with Down syndrome, as no one with Down syndrome was included in the Leqembi clinical trials to date. LuMind IDSC recommends that a safety study specifically geared to people with Down syndrome should take place prior to widespread use in the Down community.

Lecanemab (Leqembi®) is a therapeutic approved in the United States for the treatment of Alzheimer’s disease (AD) to be initiated in early AD (mild cognitive impairment [MCI] due to AD or mild AD dementia) with confirmed brain amyloid pathology. Appropriate Use Recommendations (AURs) are intended to help guide the introduction of new therapies into real-world clinical practice. Adverse events may occur with lecanemab including amyloid related imaging abnormalities (ARIA) and infusion reactions. Monitoring guidelines for these events are detailed in this AUR. Most ARIA with lecanemab is asymptomatic, but a few cases are serious or, very rarely, fatal. Microhemorrhages and rare macrohemorrhages may occur in patients receiving lecanemab. Anticoagulation increases the risk of hemorrhage, and the AUR recommends that patients requiring anticoagulants not receive lecanemab until more data regarding this interaction are available. Patients who are apolipoprotein E ε4 (APOE4) gene carriers, especially APOE4 homozygotes, are at higher risk for ARIA, and the AUR recommends APOE genotyping to better inform risk discussions with patients who are lecanemab candidates. Patients and their care partners must understand the potential benefits, the potential harms, and the monitoring requirements for treatment with this agent.

“Persons with Down syndrome develop AOAD and are amyloid positive. There is an increased occurrence of CAA in patients with Down syndrome and they should be excluded from treatment with lecanemab. Clinical trials for patients with Down syndrome are under consideration and additional data including information that may guide the use of lecanemab in this population are expected.” [p. 13]

Source: Cummings, J., Apostolova, L., Rabinovici, G.D. et al. Lecanemab: Appropriate Use Recommendations. J Prev Alzheimers Dis (2023). https://doi.org/10.14283/jpad.2023.30