LEQEMBI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LEQEMBI (LEQEMBI).
Lecanemab is a humanized monoclonal antibody that targets aggregated soluble and insoluble forms of amyloid beta, reducing amyloid plaques in the brain.
| Metabolism | Metabolized by catabolism via general protein degradation pathways; no CYP450 involvement. |
| Excretion | Primarily catabolized to amino acids; not excreted renally or hepatically in unchanged form. |
| Half-life | Terminal half-life approximately 7.6 days (range 5-12 days) after multiple doses; supports monthly dosing. |
| Protein binding | Not determined; lecanemab is a monoclonal antibody with minimal nonspecific binding. |
| Volume of Distribution | Approximately 0.122 L/kg (central volume), consistent with limited extravascular distribution typical of mAbs. |
| Bioavailability | IV administration only; bioavailability 100% for intended route. |
| Onset of Action | IV infusion: Clinical effects on amyloid plaque reduction observed after 3 months of treatment; cognitive benefit may be detectable at 6-12 months. |
| Duration of Action | Duration of action extends beyond half-life; monthly maintenance dosing required to sustain amyloid clearance. Cognitive effects persist as long as treatment continues. |
10 mg/kg intravenously every 2 weeks, administered over approximately 1 hour.
| Dosage form | INJECTABLE |
| Renal impairment | No 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 impairment | No dose adjustment required for mild hepatic impairment (Child-Pugh A). Not studied in moderate or severe hepatic impairment (Child-Pugh B or C). |
| Pediatric use | Safety and efficacy in pediatric patients have not been established. No dosing recommendations available. |
| Geriatric use | No 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. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LEQEMBI (LEQEMBI).
| Breastfeeding | It is unknown whether lecanemab is excreted in human milk or absorbed systemically after ingestion. Given the large molecular size (monoclonal antibody), excretion into milk is likely low, but not studied. M/P ratio is not available. Caution is advised; consider developmental benefits of breastfeeding versus potential exposure. |
| Teratogenic Risk | LEQEMBI (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. |
■ 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.
| Serious Effects |
["History of serious hypersensitivity to lecanemab or any excipients"]
| Precautions | ["Risk of ARIA (amyloid-related imaging abnormalities), including ARIA-E and ARIA-H","Risk of infusion-related reactions","Risk of hypersensitivity reactions"] |
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| Fetal Monitoring | No 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 Effects | No 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). |