Lecanemab autoinjector offers first at‑home maintenance option in early Alzheimer’s disease

In a significant milestone for Alzheimer’s care, the U.S. Food and Drug Administration has approved lecanemab‑irmb, a once-weekly, subcutaneous autoinjector for maintenance treatment in early Alzheimer’s disease, including mild cognitive impairment and mild dementia. This marks the first amyloid‑targeting therapy permitting at-home administration for ongoing care beyond initial intravenous treatment.¹

The approval may show a shift in maintenance therapy toward patient-centred, accessible care. For neurologists and dementia specialists, integrating this option into treatment planning may enhance both efficacy and quality of life for individuals navigating early Alzheimer’s.

Quicker alternative to hospital infusions

Lecanemab delivers 360 mg via a prefilled autoinjector in approximately 15 seconds, offering patients and caregivers an alternative to hospital infusions. After completing 18 months of intravenous (IV) therapy (10 mg/kg every two weeks), patients may opt to continue IV infusions monthly or switch to the weekly subcutaneous format.²

The from Clarity AD Phase 3 open-label extension trials. Switching to weekly subcutaneous dosing maintained clinical and biomarker benefits comparable to continued IV therapy. In over 600 patients studied, notably none of the 49 receiving 360 mg weekly experienced injection-related adverse events. Systemic reactions occurred in fewer than 1% of patients versus nearly 26% in the IV group.³

Clinical trials supporting approval

The FDA approval stems from the Clarity AD core study (NCT03887455). Patients treated with intravenous lecanemab every two weeks demonstrated a statistically significant slowing of decline compared with placebo. At 18 months, the mean difference between groups on the primary endpoint, the Clinical Dementia Rating, Sum of Boxes (CDR-SB) global cognitive and functional scale, was 0.45 points (p=0.00005).

To contextualize, an increase of 0.5-1.0 points on CDR-SB domains such as memory, community affairs and home/hobbies reflects progression from mild impairment to a loss of independence. This translates into reduced ability to live safely alone, recall recent events, manage household tasks or participate meaningfully in hobbies and intellectual activities.^4,5

Longer-term findings from the Clarity AD open-label extension (OLE) reinforced these results. Over 48 months, patients receiving lecanemab showed a -1.75-point reduction in decline on CDR-SB compared with the expected trajectory of the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort.

When benchmarked against the BioFINDER cohort, the effect was even greater, with a -2.17-point reduction in decline observed at four years.

Implications for clinical practice

• Improved accessibility and adherence: Subcutaneous delivery opens treatment access to patients in rural areas or with mobility limitations and may reduce burden on infusion centres.^3,1
• Streamlined treatment timeline: At-home administration could facilitate earlier initiation of maintenance therapy and support combination strategies targeting multifactorial disease mechanisms.³

In over 600 patients studied, notably none of the 49 receiving 360 mg weekly experienced injection-related adverse events. Systemic reactions occurred in fewer than 1% of patients versus nearly 26% in the IV group.

While the subcutaneous format shows a favourable safety profile, standard precautions remain essential including:⁶

• Baseline and routine monitoring of amyloid‑related imaging abnormalities (ARIA)
• Vigilance for injection-site reactions or hypersensitivity
• Special consideration in patients with APOE ε4 genotype or cerebral amyloid angiopathy.

Subcutaneous lecanemab is scheduled to launch in the US on October 6, 2025.¹

Further content on Alzheimer’s disease

This content has been developed independently by Touch Medical Media for touchNEUROLOGY.

Editor: Katey Gabrysch, Editorial Director.

Disclosures: This short article was prepared by touchNEUROLOY and was developed and edited by human editors. No fees or funding were associated with its publication. touchNEUROLOGY utilize AI as an editorial tool (ChatGPT (GPT-4o) [Large language model]. https://chat.openai.com/chat).

Cite: Lecanemab autoinjector offers at‑home maintenance option in early Alzheimer’s disease. touchNEUROLOGY. 01 September 2025.

References:

1. PR Newswire. FDA approves Leqembi IQLIK (lecanemab-irmb) subcutaneous injection for maintenance dosing for the treatment of early Alzheimer’s disease. 2025. Available at: https://www.prnewswire.com/news-releases/fda-approves-leqembi-iqlik-lecanemab-irmb-subcutaneous-injection-for-maintenance-dosing-for-the-treatment-of-early-alzheimers-disease-302542371.html (accessed 1 September 2025).

2. van Dyck CH, Swanson CJ, Aisen P, et al. Lecanemab in early Alzheimer’s disease. N Engl J Med. 2023;388:9–21. doi:10.1056/NEJMoa2212948.

3. Alzheimer’s Drug Discovery Foundation. FDA approval of Leqembi subcutaneous formulation charts path to combination therapies for Alzheimer’s disease. 2025. Available at: https://www.alzdiscovery.org/news-room/announcements/fda-approval-of-leqembi-subcutaneous-formulation-charts-path-to-combination-therapies-for-alzheimers-disease (accessed 1 September 2025).

4. Cohen S, Cummings J, Aisen P, et al. Lecanemab in early Alzheimer’s disease: 18-month results from the Clarity AD study. J Prev Alzheimers Dis. 2022;9:507–22. doi:10.14283/jpad.2022.70.

5. Amin L, Harris DA. Aβ receptors specifically recognize molecular features displayed by fibril ends and neurotoxic oligomers. Nat Commun. 2021;12:3451. doi:10.1038/s41467-021-23507-z.

6. HCPLive. FDA approves subcutaneous lecanemab-irmb (Leqembi) for early Alzheimer disease. 2025. Available at: https://www.hcplive.com/view/fda-approves-subcutaneous-lecanemab-irmb-leqembi-for-early-alzheimer-disease (accessed 1 September 2025).

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