Lecanemab

LEQEMBI

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Pronunciation: lek-AN-e-mab (le-KEM-bee)

Lecanemab ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Lecanemab ballicule

Lecanemab LEQEMBI mascot mnemonic cartoon — Visual mnemonic: Lecanemab mascot
**“Lickin’ β”**

What it isMonoclonal antibody targeting amyloid protofibrils; early Alzheimer disease with confirmed amyloid pathology.

Why this oneIt preferentially targets soluble protofibrils rather than mature plaque and modestly slows decline rather than restoring cognition.

What limits it⚑ ARIA edema and hemorrhage require MRI surveillance; APOE4 homozygotes face the highest risk, especially with anticoagulation.

Lecanemab molecular structure (skeletal formula) — Molecular structure: Lecanemab

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Amyloid related imaging abnormalities (ARIA-E and ARIA-H); usually asymptomatic but serious/life-threatening events, including fatal, can occur. Serious intracerebral hemorrhages >1 cm have occurred. ApoE e4 homozygotes have higher ARIA incidence; test ApoE e4 status before initiating.

FDA dosing	Population	Start	Target	Max
Alzheimer's disease (initiate in mild cognitive impairment or mild dementia stage)	Adults	IV: 10 mg/kg every 2 weeks; or SC (IQLIK): 500 mg once weekly	After 18 months, continue starting dosage or transition to maintenance - IV 10 mg/kg every 4 weeks, or SC 360 mg once weekly

Renal Undefined (not studied; not expected to undergo renal elimination)

Hepatic Undefined (not studied; not expected to be metabolized by hepatic enzymes)

See label tables for switching routes and transitioning to maintenance dosing intervals

Instructions

Confirm amyloid beta pathology before initiating
Obtain baseline brain MRI, then MRI after 1, 2, 3, and 6 months; manage ARIA with dosing interruption per severity
IV infusion over ~1 hour after dilution in 250 mL 0.9% sodium chloride
SC injection into abdomen or upper thigh; rotate sites
Enhanced clinical vigilance for ARIA during first 14 weeks

Available strengths

inj 100 mg/mL

Contraindications

Serious hypersensitivity to lecanemab-irmb or to any of the excipients (reactions have included angioedema and anaphylaxis)

Cautions

Amyloid related imaging abnormalities (ARIA-E/ARIA-H); increased risk in ApoE e4 homozygotes and in patients with pretreatment microhemorrhages/superficial siderosis
Intracerebral hemorrhage; caution with antithrombotic/thrombolytic therapy
Hypersensitivity reactions including anaphylaxis
Infusion-related reactions

Adverse reactions

Infusion-related reactions
ARIA-H (microhemorrhage/superficial siderosis)
ARIA-E (edema/effusion)
Headache
Injection-related reactions (SC)

Pregnancy No adequate human data; no animal studies conducted.

Lactation No data on presence in human milk; monoclonal antibodies generally show low passage into milk.

Cost

Lecanemab (LEQEMBI)

Strength		#/mo	generic $/unit	CostPlus
100 mg/mL	inj	per unit		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Lecanemab is administered under clinical supervision and dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

⚠ BOXED WARNING

Amyloid-related imaging abnormalities

Principal riskARIA edema and hemorrhage; highest risk in APOE4 homozygotes

Classes and tags

Clinical profile

Therapeutic safety burden4 / 4

Overdose danger0 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Legacy pregnancy categoryN/A (post-2015 labeling)

Defining liabilityAmyloid-related edema and potentially fatal intracerebral hemorrhage

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