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Registry Hub
Monoclonal Antibody/Prescription

LEQEMBI

LEQEMBI

Clinical safety rating

caution

Comprehensive clinical and safety monograph for LEQEMBI (LEQEMBI).


What is LEQEMBI?

Comprehensive clinical and safety monograph for LEQEMBI (LEQEMBI).

Indications & Uses

Treatment of Alzheimer disease (early stage)

Compare LEQEMBI vs ADUHELM →View all Monoclonal Antibody drugs →

Mechanism of Action

Lecanemab is a humanized monoclonal antibody that targets aggregated soluble and insoluble forms of amyloid beta, reducing amyloid plaques in the brain.

What the body does with it

MetabolismMetabolized by catabolism via general protein degradation pathways; no CYP450 involvement.
ExcretionPrimarily catabolized to amino acids; not excreted renally or hepatically in unchanged form.
Half-lifeTerminal half-life approximately 7.6 days (range 5-12 days) after multiple doses; supports monthly dosing.
Protein bindingNot determined; lecanemab is a monoclonal antibody with minimal nonspecific binding.
Volume of DistributionApproximately 0.122 L/kg (central volume), consistent with limited extravascular distribution typical of mAbs.
BioavailabilityIV administration only; bioavailability 100% for intended route.
Onset of ActionIV infusion: Clinical effects on amyloid plaque reduction observed after 3 months of treatment; cognitive benefit may be detectable at 6-12 months.
Duration of ActionDuration of action extends beyond half-life; monthly maintenance dosing required to sustain amyloid clearance. Cognitive effects persist as long as treatment continues.
Molecular Weight146000

Classification & Brands

Dosing & administration

10 mg/kg intravenously every 2 weeks, administered over approximately 1 hour.

Dosage formINJECTABLE
Renal impairmentNo dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min/1.73 m²). Not studied in severe renal impairment (eGFR <30 mL/min/1.73 m²).
Liver impairmentNo dose adjustment required for mild hepatic impairment (Child-Pugh A). Not studied in moderate or severe hepatic impairment (Child-Pugh B or C).
Pediatric useSafety and efficacy in pediatric patients have not been established. No dosing recommendations available.
Geriatric useNo specific dose adjustment required based on age alone. Dosing is based on body weight (10 mg/kg) every 2 weeks. Clinical studies included patients up to 90 years of age.

Use during pregnancy

1st trimesterNo adequate human data; animal studies show potential risk. Use only if benefit outweighs risk.
2nd trimesterNo adequate human data; potential risk based on animal studies.
3rd trimesterNo adequate human data; potential risk based on animal studies.

Clinical note

Comprehensive clinical and safety monograph for LEQEMBI (LEQEMBI).

Placental transferExpected to cross the placenta as a humanized monoclonal antibody (IgG1), especially in second and third trimesters.
BreastfeedingNot recommended during breastfeeding due to unknown secretion into human milk and potential for adverse reactions in the infant.
Lactation RatingL4 - Possibly Hazardous
Teratogenic RiskLEQEMBI (lecanemab) is an anti-amyloid beta monoclonal antibody. There are no adequate human studies on fetal risk. In animal reproductive studies, no adverse developmental effects were observed at doses up to 15 times the human exposure. However, IgG antibodies are known to cross the placenta, with increasing transfer during the third trimester. Therefore, potential fetal exposure occurs, especially in later pregnancy. Risk cannot be excluded; use only if maternal benefit outweighs fetal risk.
Fetal MonitoringNo specific fetal monitoring required beyond standard prenatal care. Monitor for infusion-related reactions (hypersensitivity, hypotension, fever) during administration. In clinical trials, amyloid-related imaging abnormalities (ARIA) were monitored with MRI; however, ARIA is not specific to pregnancy. No additional maternal monitoring mandated by pregnancy.
Fertility EffectsNo human data on fertility effects. Animal studies showed no impairment of fertility at doses up to 15 times the human exposure. Potential effects on ovarian or testicular function are unlikely based on mechanism of action (amyloid beta target not involved in reproduction).

Warnings & precautions

■ FDA Black Box Warning

Lecanemab may cause amyloid-related imaging abnormalities (ARIA), including ARIA with edema (ARIA-E) and ARIA with hemosiderin deposition (ARIA-H). ARIA can be serious and life-threatening.

Side Effect Profile

Serious Effects

Absolute Contraindications

History of severe allergic reaction to lecanemab or any excipientsConcurrent use with other anti-amyloid monoclonal antibodies unless specifically indicated

Clinical Precautions

PrecautionsRisk of ARIA (amyloid-related imaging abnormalities), including ARIA-E and ARIA-H, Risk of infusion-related reactions, Risk of hypersensitivity reactions
Food/DietaryNo known food interactions. Grapefruit or other CYP450 substrates have no significant interaction. Avoid alcohol due to potential additive CNS effects, though no direct interaction established.

Clinical Tips & Counseling

Clinical PearlsLEQEMBI (lecanemab) is an anti-amyloid beta monoclonal antibody for early Alzheimer disease. Confirm patient eligibility via amyloid PET or CSF analysis. Administer via IV infusion over approximately 1 hour every 2 weeks. Monitor for amyloid-related imaging abnormalities (ARIA), including ARIA-E (edema) and ARIA-H (hemorrhage), with MRI scans before the 5th, 7th, and 14th infusions. Assess for headache, confusion, or visual changes as potential ARIA symptoms. Patients with homozygous APOE4 genotype have higher risk of ARIA; consider APOE genotyping. Concomitant use of antithrombotic agents may increase risk of ARIA-H; weigh risks versus benefits. Do not abruptly discontinue; no tapering required. Lecanemab is not approved for mild, moderate, or severe Alzheimer disease beyond early stage.
Patient AdviceLEQEMBI is used to treat early Alzheimer disease and works by reducing amyloid plaques in the brain. · This medication is given as an intravenous (IV) infusion every 2 weeks, each lasting about 1 hour. · You will need regular MRI scans to check for brain swelling or small bleeds (ARIA). · Tell your doctor immediately if you have new headache, confusion, vision changes, dizziness, or trouble walking. · Inform your healthcare provider about all other medicines, especially blood thinners like warfarin, apixaban, or aspirin. · Do not abruptly stop treatment; consult your doctor if you need to discontinue.

LEQEMBI Interactions

Loading safety data…

This overview is compiled from peer-reviewed clinical sources and FDA labeling. It's here to support — not replace — clinical judgment. Always verify dosing against your institution's current protocols before prescribing.

On this page

Mechanism of ActionDosing & administrationUse during pregnancyWarnings & precautionsDrug interactions

Compare with

ADUHELMANTHIMARZERRABENLYSTABEYFORTUS

External sources

DailyMed (NIH) PubMed OpenFDA