Lecanemab: Uses, Side Effects, Dosage - Drugvu

ℹ️ Compiled from public regulatory records · Last regulator revision: May 29, 2026🚩 Report this page

Lecanemab

Other Anti-Dementia Drugs

Sold as Leqembi

GB MHRAEU EMACA Health Canada

Drug class: Other Anti-Dementia Drugs
Availability: See label
Routes: Intravenous
Markets covered: 3
Products on record: 3

Overview

Lecanemab is an active pharmaceutical ingredient in the Other Anti-Dementia Drugs group (N06DX). The information below is compiled per regulator from the product labels on record, with direct links to the original documents.

Regulatory status by market

Market	Regulator	Products	Last revision
GB United Kingdom	MHRA	1	May 29, 2026
EU European Union	EMA	1	May 4, 2026
CA Canada	Health Canada	1	December 23, 2025

GBUnited Kingdom· MHRA

1 product

Uses

GBOfficial regulatory label· revised May 29, 2026[1]

1).

How to take

GBOfficial regulatory label· revised May 29, 2026

EUEuropean Union· EMA

1 product

Uses

EUOfficial regulatory label· revised May 4, 2026[2]

4).

How to take

EUOfficial regulatory label· revised May 4, 2026

CACanada· Health Canada

1 product

1 product on record with this regulator. Detailed label text (uses, dosage, side effects) is being ingested — the original document is linked under Sources [3].

Brands in Canada (1)

LEQEMBIEISAI LIMITED

Sources & citations

[1]MHRA (UK) · PLGB339670027 · revised May 29, 2026
[2]European Medicines Agency · EMEA/H/C/005966 · revised May 4, 2026
[3]Health Canada (DPD) · 02562383 · revised December 23, 2025

Information on this page is compiled from public regulatory records. Drugvu is not affiliated with any regulator or pharmaceutical manufacturer. This is not medical advice. Always consult a qualified healthcare professional.

Treatment should be initiated and supervised by physicians experienced in the diagnosis and treatment of Alzheimer’s disease. 1). 1). Prior to testing patients should be appropriately counselled and consented according to national or local guidelines, as applicable.
Posology The recommended initial dosing regimen is 10 mg/kg administered as an intravenous (IV) infusion over approximately one hour, once every 2 weeks. After 18 months, the regimen of 10 mg/kg once every two weeks may be continued, or a transition to the maintenance dosing regimen of 10 mg/kg once every 4 weeks may be considered.
Treatment with lecanemab should be discontinued once the patient progresses to moderate Alzheimer’s disease. The efficacy of continued treatment in patients with moderate Alzheimer’s disease has not been established. 1). Dose Adjustments No dose reductions are recommended.
If a patient develops amyloid related imaging abnormalities (ARIA), see detailed Magnetic Resonance Imaging (MRI) monitoring and dosing interruption guidelines below. 4). Access to MRI should be available during the treatment period of lecanemab.
Obtain a recent brain MRI prior to initiating treatment with lecanemab. Obtain an MRI prior to the 5th, 7th and 14th infusions. Enhanced clinical vigilance for ARIA is recommended during the first 14 weeks of treatment with lecanemab.
4), clinical evaluation should be performed, including an MRI if indicated. Recommendations for Dosing Interruptions or Treatment Discontinuation in Patients with ARIA ARIA-E Table 1: Dosing Recommendations for Patients with ARIA-E Clinical symptoms ARIA-E Severity on MRI1 Mild Moderate Severe Asymptomatic May continue dosing based on clinical judgement Suspend dosing Suspend dosing Symptomatic Suspend dosing 1See Table 3 for MRI radiographic severity.
Dosing may continue in asymptomatic, mild radiographic ARIA-E cases based on clinical judgement with enhanced clinical monitoring and follow-up MRI scans starting 2 months after occurrence and every 1 or 2 months thereafter until ARIA-E has resolved.
Suspend dosing for any symptomatic or radiographically moderate or severe ARIA-E. A follow-up MRI should be performed to assess for resolution 2 to 4 months after initial identification. 4), if present, resolve, resumption of dosing should be guided by clinical judgement.
8).
ARIA-H Table 2:
Dosing Recommendations for Patients with ARIA-H Clinical symptoms ARIA-H Severity on MRI1 Mild Moderate Severe Asymptomatic May continue dosing based on clinical judgement Suspend dosing Symptomatic Suspend dosing Permanently discontinue treatment 1See Table 3 for MRI radiographic severity.
Dosing may continue in asymptomatic, mild radiographic ARIA-H cases based on clinical judgement with enhanced clinical monitoring and follow-up MRI scans starting 2 months after occurrence and every 1 or 2 months thereafter until ARIA-H has stabilised.
Suspend dosing for any symptomatic or radiographically moderate ARIA-H. A follow-up MRI should be performed to assess for stabilisation 2 to 4 months after initial identification. 4), if present, resolve, resumption of dosing should be guided by clinical judgement.
8). In the event of radiographically severe ARIA-H, treatment with lecanemab should be permanently discontinued. Radiographic Findings The radiographic severity of ARIA associated with lecanemab was classified by the criteria shown in Table 3.
Table 3:
ARIA MRI Severity Classification Criteria Radiographic Severity1 ARIA Type Mild Moderate Severe ARIA-E FLAIR hyperintensity confined to sulcus and/or cortex/subcortex white matter in one location <5 cm FLAIR hyperintensity 5 to 10 cm in single greatest dimension, or more than 1 site of involvement, each measuring <10 cm FLAIR hyperintensity >10 cm with associated gyral swelling and sulcal effacement.
One or more separate/ independent sites of involvement may be noted. ARIA-H microhaemorrhag e ≤4 new incident microhaemorrhages 5 to 9 new incident microhaemorrhages 10 or more new incident microhaemorrhages ARIA-H superficial siderosis 1 focal area of superficial siderosis 2 focal areas of superficial siderosis >2 areas of superficial siderosis 1Radiographical severity is defined by the total number of new microhaemorrhages from baseline or total number of areas for superficial siderosis.
Intracerebral Haemorrhage Lecanemab should be permanently discontinued if intracerebral haemorrhage greater than 1 cm in diameter occurs. Delayed or missed doses If an infusion is missed, administer the next dose as soon as possible.
1). Renal impairment No specific dose adjustment is necessary in patients […]

Side effects & warnings

GBOfficial regulatory label· Adverse reactions· revised May 29, 2026[1]

Summary of the safety profile The safety of lecanemab has been evaluated in 2203 patients who received at least one dose of lecanemab. In the double-blind, placebo-controlled period of Study 301 in patients with mild cognitive impairment due to Alzheimer’s disease or mild Alzheimer’s disease dementia, a total of 898 patients received lecanemab at the recommended dose of 10 mg/kg every 2 weeks, of which 757 patients were non-carriers or heterozygotes (the indicated population).
Of the patients treated with lecanemab 31% (278/898) were non-carriers, 53% (479/898) were heterozygotes and 16% (141/898) were homozygotes. With the exception of events of ARIA, the safety profile was the same across genotypes. In the indicated population, the most common adverse reactions were infusion-related reaction (26%), ARIA-H (13%), fall (11%), headache (11%) and ARIA-E (9%).
Tabulated list of adverse reactions Adverse reactions reported in clinical trials are listed below in Table 4. The adverse reactions are listed by MedDRA System Organ Class and categories of frequency. Frequencies are defined as: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), rare (≥1/10,000 to <1/1,000), very rare (<1/10,000), not known (cannot be estimated from the available data).
Within each System Organ Class and frequency grouping, adverse reactions are presented in order of decreasing seriousness Table 4: Adverse reactions System Organ Class (SOC) Very common (≥1/10) Common (≥1/100 to <1/10) Uncommon (≥1/1,000 to <1/100) Immune system disorders Hypersensitivity reactions Anaphylaxis Nervous system disorders ARIA-H1 Headache ARIA-E2 Intracerebral haemorrhage Cardiac disorders Atrial fibrillation Skin and subcutaneous tissue disorders Rash3 General disorders and administration site conditions Infusion-related reactions 1ARIA-H: Amyloid related imaging abnormality-microhaemorrhage and haemosiderin deposit; Superficial siderosis of central nervous system, and Cerebellar microhaemorrhage.
2ARIA-E is common in the indicated population and very common in the homozygote population. 3Rash: acne, erythema, infusion-site rash, injection-site rash, rash, rash erythematous, rash pruritic, skin reactions, and urticaria. Description of selected adverse reactions Incidence of ARIA in the Indicated Population Symptomatic ARIA occurred in 2% (16/757) of patients on lecanemab who are non- carriers and heterozygotes in Study 301.
4% (3/757) of patients on lecanemab. Clinical symptoms associated with ARIA resolved in 75% (12/16) of patients during the 18-month study period; clinical symptoms in 50% of these patients resolved within 3 days. Including asymptomatic radiographic events, ARIA was observed in 17% (128/757) of patients on lecanemab compared to 7% (55/764) of patients on placebo.
ARIA-E was observed in 9% (67/757) of patients on lecanemab compared with 1% (10/764) of patients on placebo. The majority of ARIA-E was asymptomatic, with symptomatic ARIA-E reported in 2% (12/757) patients on lecanemab and no patients on placebo ARIA-H was observed in 13% (98/757) of patients on lecanemab compared with 7% (52/764) of patients on placebo.
1% (1/764) on placebo. ARIA-H and ARIA-E can occur together. , ARIA-H in patients who did not also experience ARIA-E) for lecanemab compared to placebo. The majority of ARIA-E radiographic events occurred early in treatment (within the first 7 doses), although ARIA-E can occur at any time and patients can have more than 1 episode.
3% (2/757) of patients. Resolution on MRI occurred in 64% (43/67) of patients by 12 weeks, 87% (58/67) by 17 weeks, and 100% (67/67) overall after detection, compared with 80% (8/10) of patients on placebo. 3% (2/757) of patients. ARIA-H stabilised in 79% (77/97) of patients on lecanemab compared with 75% (39/52) of patients on placebo, either at the first follow-up MRI or within 20 weeks for most patients.
2 for MRI radiographic severity. Recurrence of ARIA in the Indicated Population ARIA-E was observed in 9% (67/757) of patients on lecanemab, of which 88% (59/67) continued on lecanemab with or without dose interruption. Among those that continued lecanemab, 14% (8/59) experienced a recurrence of ARIA-E.
ARIA-H (with or without concurrent ARIA-E) was observed in 13% (98/757) of patients on lecanemab and 7% (52/764) of patients on placebo, of which 80% (78/98) and 77% (40/52) continued treatment with or without dose interruption, respectively.
Among those that continued, 36% (28/78) of patients on lecanemab and 30% (12/40) of patients on placebo experienced a recurrence of ARIA-H. 1% (1/764) of patients on placebo. 7% (3/450) of patients who did not. 5% (1/68 patients) compared to no patients on placebo.
Fatal events of intracerebral haemorrhage have been observed in patients taking lecanemab. APOE ε4 Carrier […]

GBOfficial regulatory label· Warnings and precautions· revised May 29, 2026[1]

Controlled access programme In order to promote the safe and effective use of lecanemab, initiation of treatment in all patients should be through a central registration system implemented as part of a controlled access programme. Traceability In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.
Hypersensitivity reactions Hypersensitivity reactions, including angioedema, bronchospasm, and anaphylaxis, have occurred in patients who were treated with lecanemab. Promptly discontinue the infusion upon the first observation of any signs or symptoms consistent with a hypersensitivity-type reaction and initiate appropriate therapy.
Amyloid Related Imaging Abnormalities (ARIA) Lecanemab can cause ARIA, characterised as ARIA-E, which can be observed on MRI as brain oedema or sulcal effusions, and ARIA-H, which includes microhaemorrhage and superficial siderosis.
ARIA can occur spontaneously in patients with Alzheimer’s disease. ARIA-H associated with lecanemab generally occurs in association with an occurrence of ARIA-E. ARIA usually occurs early in treatment and is usually asymptomatic, although serious and life-threatening events, including seizure and status epilepticus, rarely can occur.
When present, reported symptoms associated with ARIA may include headache, confusion, visual changes, dizziness, nausea, and gait difficulty. Focal neurologic deficits may also occur. 8). 8). 2. ApoE ε4 Carrier Status and Risk of ARIA Approximately 15% of Alzheimer’s disease patients are ApoE ε4 homozygotes.
8). 1). 8). 8). Concomitant Antithrombotic Medication Baseline use of antithrombotic medication (aspirin, other antiplatelet agents, or anticoagulants) was allowed in Study 301 if the patient was on a stable dose. The majority of exposures to antithrombotic medications were to aspirin.
Aspirin and other antiplatelet agents were used in the trial with no increase in the risk of ARIA-E, ARIA-H or intracerebral haemorrhage with lecanemab. g. tissue plasminogen activator) to a patient already being treated with lecanemab: • If anticoagulation needs to be commenced during therapy with lecanemab (for example incident arterial thromboses, acute pulmonary embolism or other life- threatening indications) then lecanemab should be paused.

This is not medical advice. Consult a qualified healthcare professional.

Treatment should be initiated and supervised by physicians experienced in the diagnosis and treatment of Alzheimer’s disease with timely access to Magnetic Resonance Imaging (MRI). Lecanemab infusions should be administered by qualified healthcare professionals trained to monitor for, recognize and manage infusion-related reactions.
Patients treated with lecanemab must be given the patient card and be informed about the risks of lecanemab (see also package leaflet). 3 ApoE4 Testing ApoE4 genotype should be assessed by a CE-marked in vitro diagnostic (IVD) with the corresponding intended purpose.
1). 1). Prior to testing patients should be appropriately counselled and consented according to national or local guidelines, as applicable. Posology The recommended dose of lecanemab is 10 mg/kg body weight administered as an intravenous (IV) infusion once every 2 weeks.
Treatment with lecanemab should be discontinued once the patient progresses to moderate Alzheimer’s disease. During treatment with lecanemab, cognitive function testing and clinical symptom assessment should occur approximately every 6 months.
The cognitive testing and symptom progression should be used to assess whether the patient has progressed to moderate Alzheimer's dementia, and/or if the clinical course otherwise suggests that lecanemab has not demonstrated effectiveness in the patient, and inform the decision as to whether treatment with lecanemab should be discontinued.
Monitoring for Amyloid Related Imaging Abnormalities (ARIA) Lecanemab can cause ARIA, characterized as ARIA with oedema (ARIA-E), which can be observed on MRI as brain oedema or sulcal effusions, and ARIA with haemosiderin deposition (ARIA-H), which includes microhaemorrhage and superficial siderosis.
In addition to ARIA, intracerebral haemorrhages greater than 1 cm in diameter have occurred in patients treated with lecanemab. Obtain a recent (within 6 months) baseline brain MRI prior to initiating treatment with lecanemab to evaluate for pre-existing ARIA.
Obtain an MRI prior to the 3rd, 5th, 7th and 14th infusions. In general, the MRI should be performed within approximately one week before the scheduled infusion of lecanemab and reviewed prior to proceeding with the infusion. 4). Recommendations for Dosing Interruptions or Treatment Discontinuation in Patients with ARIA ARIA-E Dosing may continue in asymptomatic, mild radiographic ARIA-E cases.
Suspend dosing for any symptomatic or radiographically moderate or severe ARIA-E. A follow-up MRI to assess for resolution 2 to 4 months after initial identification should be performed. Once the MRI demonstrates radiographic resolution and symptoms, if present, resolve, resumption of dosing should be guided by clinical judgment.
4). Use clinical judgment in considering whether to continue dosing in patients with recurrent ARIA-E. 8). ARIA-H Dosing may continue in asymptomatic, mild radiographic ARIA-H cases. Suspend dosing for any symptomatic mild or moderate or radiographically moderate ARIA-H.
A follow-up MRI to assess for stabilisation 2 to 4 months after initial identification should be performed. 8). In the event of radiographically or symptomatic severe ARIA-H, 4 treatment with lecanemab should be permanently discontinued.
4). Intracerebral Haemorrhage Lecanemab should be permanently discontinued if intracerebral haemorrhage greater than 1 cm in diameter occurs. Delayed or missed doses If an infusion is missed, the next dose should be administered as soon as possible.
1). 2). 2). Paediatric population There is no relevant use of lecanemab in the paediatric population. Method of administration Lecanemab is for intravenous use only. Lecanemab is administered as an intravenous infusion over approximately 1 hour once every 2 weeks.
4). Lecanemab is diluted prior to intravenous infusion. 6.

Side effects & warnings

EUOfficial regulatory label· Adverse reactions· revised May 4, 2026[2]

Summary of the safety profile The safety of lecanemab has been evaluated in 2203 patients who received at least one dose of lecanemab. In the double-blind, placebo-controlled period of Study 301 in patients with mild cognitive impairment due to Alzheimer’s disease or mild Alzheimer’s disease dementia, a total of 898 patients received 9 lecanemab at the recommended dose of 10 mg/kg every 2 weeks, of which 757 patients were non- carriers or heterozygotes (the indicated population).
Of the patients treated with lecanemab 31% (278/898) were non-carriers, 53% (479/898) were heterozygotes and 16% (141/898) were homozygotes. With the exception of events of ARIA, the safety profile was the same across genotypes. Seizures including status epilepticus have been reported with lecanemab treatment in the clinical trials.
In the indicated population, the most common adverse reactions were infusion-related reaction (26%), ARIA-H (13%), headache (11%) and ARIA-E (9%). 1% (1/764) patients on placebo. Fatal events of intracerebral haemorrhage in patients receiving lecanemab have been observed.
Tabulated list of adverse reactions The following adverse reactions listed in Table 2 below have been reported in clinical trials with lecanemab. The adverse reactions are presented as MedDRA preferred terms under the MedDRA System Organ Class.
Adverse reactions are ranked according to system organ class, using the following convention: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1 000 to <1/100), rare (≥1/10 000 to <1/1 000), very rare (<1/10 000), not known (cannot be estimated from the available data).
Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.
Table 2:
Adverse reactions System Organ Class (SOC) Adverse reaction Frequency category Immune system disorders Hypersensitivity reactions1 Common Delayed hypersensitivity reactions2,3 Common Nervous system disorders Headache Very Common ARIA4 Very Common ARIA-H5,6 Very Common Symptomatic ARIA-H7 Common Cerebral microhaemorrhage ≤10 Very Common Cerebral microhaemorrhage >10 Common Superficial siderosis Common Intracerebral haemorrhage >1 cm Uncommon ARIA-E8,9 Common Symptomatic ARIA-E7 Common Cardiac disorders Atrial fibrillation Common Gastrointestinal disorders Nausea Common General disorders and administration site conditions Infusion related reactions10 Very Common 1 Includes angioedema, bronchospasm, anaphylaxis, rash and headache.
2 Includes rash, headache, rhinorrhoea, rhinitis and hair loss. 3 Occurred 24 hours after infusion. 4 ARIA: Includes radiographic ARIA-E, symptomatic ARIA-E, radiographic ARIA-H and symptomatic ARIA-H. 5 ARIA-H: Includes radiographic ARIA-H and symptomatic ARIA-H.
6 ARIA-H: Amyloid related imaging abnormality-microhaemorrhage and haemosiderin deposit; Superficial siderosis of central nervous system, and Cerebellar microhaemorrhage. 10 7 Includes common symptom of headache; uncommon symptoms of confusion, visual changes (diplopia, glare, vision blurred, visual acuity reduced, visual impairment), dizziness, nausea, gait difficulty and seizures.
8 ARIA-E: Includes radiographic ARIA-E and symptomatic ARIA-E. 9 ARIA-E is common in the indicated population and very common in the homozygote population. 10 Includes infusion related reaction and infusion site reaction. Description of selected adverse reactions Incidence of ARIA in the Indicated Population In Study 301, symptomatic ARIA occurred in 2% (16/757) patients on lecanemab who are non- carriers and heterozygotes.
4% (3/757) of patients on lecanemab. Clinical symptoms associated with ARIA resolved in 75% (12/16) of patients during the period of observation. Including asymptomatic radiographic events, ARIA was observed in 17% (128/757) of patients on lecanemab compared to 7% (55/764) patients on placebo in Study 301.
In Study 301, ARIA-E was observed in 9% (67/757) of patients on lecanemab compared with 1% (10/764) of patients on placebo. The majority of ARIA-E was asymptomatic, with symptomatic ARIA-E reported in 2% (12/757) of patients on lecanemab and no patients on placebo.
When present, reported symptoms associated with ARIA-E included headache (50%, 6/12), confusion (17%, 2/12), dizziness (8%, 1/12) and nausea (8%, 1/12). Focal neurologic deficits (8%, 1/12) also occurred. ARIA-H was observed in 13% (98/757) of patients on lecanemab compared with 7% (52/764) of patients on placebo.
1% (1/764) of patients on placebo. ARIA-H and ARIA-E can occur together. e. ARIA-H in patients who did not also experience ARIA-E) for lecanemab compared to placebo. The majority of ARIA-E radiographic events occurred early in treatment (within the first 7 doses), although ARIA-E can occur at any time and patients can have more than 1 episode.
3% (2/757) of patients. Resolution on MRI occurred in 64% (43/67) of patients by 12 weeks, 87% (58/67) by 17 weeks, and 100% (67/67) overall after detection, compared with 80% (8/10) of patients on placebo. 3% (2/757) of patients. 4 for MRI radiographic severity.
Recurrence of ARIA in the Indicated Population ARIA-E was observed in 9% (67/757) of patients on lecanemab, of which […]

EUOfficial regulatory label· Warnings and precautions· revised May 4, 2026[2]

Controlled access programme and registry In order to promote the safe and effective use of lecanemab, initiation of treatment in all patients should be through a central registration system implemented as part of a controlled access programme.
5 Traceability In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded. Hypersensitivity reactions Hypersensitivity reactions, including angioedema, bronchospasm, and anaphylaxis, have occurred in patients who were treated with lecanemab which may be serious.
2). Amyloid beta pathology The presence of amyloid beta pathology must be confirmed via an appropriate test prior to initiating treatment. Amyloid Related Imaging Abnormalities (ARIA) ARIA can occur spontaneously in patients with Alzheimer’s disease.
ARIA-H generally occurs in association with an occurrence of ARIA-E. ARIA usually occurs early in treatment and is usually asymptomatic, although serious and life- threatening events, including seizure and status epilepticus, rarely can occur.
When present, reported symptoms associated with ARIA may include headache, confusion, visual changes, dizziness, nausea, and gait difficulty. Focal neurologic deficits may also occur. In patients who experienced ARIA on placebo or with lecanemab, 1/3 experienced recurrent ARIA.
8). 8). 8). In addition to ARIA, intracerebral haemorrhages greater than 1 cm in diameter have occurred in patients treated with lecanemab. 8). Monitoring for ARIA Baseline brain MRI and periodic monitoring with MRI are recommended. Enhanced clinical vigilance for ARIA is recommended during the first 14 weeks of treatment with lecanemab.
2). Radiographic Findings The radiographic severity of ARIA associated with lecanemab was classified by the criteria shown in Table 1. 6 Table 1: ARIA MRI Classification Criteria ARIA Type Radiographic Severity1 Mild Moderate Severe ARIA-E FLAIR hyperintensity confined to sulcus and/or cortex/subcortex white matter in one location <5 cm FLAIR hyperintensity 5 to 10 cm in single greatest dimension, or more than 1 site of involvement, each measuring <10 cm FLAIR hyperintensity >10 cm with associated gyral swelling and sulcal effacement.

This is not medical advice. Consult a qualified healthcare professional.

Overview

Regulatory status by market

GBUnited Kingdom· MHRA

EUEuropean Union· EMA

CACanada· Health Canada

Drugs in the same class

Sources & citations