Section 05 · Monograph
Lecanemab SC
Reviewed Nov 2026FDA label
Leqembi IqlikAnti-amyloid mAb · SC
- Forms
- SC autoinjector: 360mg/1.8mL
- Dose
- Maintenance after 18 months of IV therapy: 360mg SC once weekly
- MOA
- Binds amyloid-beta protofibrils
Black Box Warning
- Amyloid-related imaging abnormalities (ARIA), including edema (ARIA-E) and hemosiderin deposition/microhemorrhage (ARIA-H), can be serious and life-threatening; ApoE epsilon-4 homozygotes have the highest risk — baseline MRI, monitoring MRIs and consideration of ApoE genotyping are required
Indications
- Alzheimer's disease in patients with mild cognitive impairment or mild dementia stage — subcutaneous autoinjector (Leqembi Iqlik) for maintenance dosing after 18 months of IV therapyFDA-labeled
Mechanism of Action
- Humanized IgG1 monoclonal antibody that binds soluble amyloid-beta protofibrils and plaque, promoting clearance
Full Dosing
Adult / usual
- After 18 months of IV lecanemab 10mg/kg every 2 weeks: either continue IV 10mg/kg every 4 weeks, or switch to 360mg SC once weekly using the 360mg/1.8mL autoinjector (injection takes about 15 seconds)
- Confirm amyloid pathology and obtain baseline MRI before initiating therapy; follow label MRI surveillance schedule
Contraindications
- Serious hypersensitivity to lecanemab or any excipient
Drug Interactions
- Anticoagulants and thrombolytics increase the risk of intracerebral hemorrhage — use caution
Adverse Effects
- ARIA-E and ARIA-H
- Injection-site reactions (SC); infusion-related reactions (IV)
- Headache, falls
Monitoring Parameters
- MRI surveillance per label
- ApoE epsilon-4 genotype status
- New headache, confusion, visual change, focal deficits or seizures
Pregnancy & Lactation
- Not studied in pregnancy or lactation; not indicated in reproductive-age patients