Leqembi® approved for IV maintenance treatment in the United Kingdom

Rhea-AI Summary

BioArctic (NASDAQ: B) partner Eisai received MHRA approval in the United Kingdom for Leqembi (lecanemab) as a once-every-four-weeks IV maintenance treatment for early Alzheimer’s disease on November 14, 2025.

After an initial 18-month induction of 10 mg/kg every two weeks, patients may be transitioned to 10 mg/kg every four weeks or remain on the two-week schedule. Leqembi previously received a UK approval in August 2024 for treatment of MCI and mild dementia due to Alzheimer’s in ApoE ε4 heterozygotes and non-carriers. BioArctic and Eisai are preparing joint commercialization in the Nordic region, where BioArctic holds commercialization rights.

Positive

• MHRA approval for IV maintenance dosing every 4 weeks in the UK
• Label allows transition after 18 months from biweekly to monthly dosing
• BioArctic retains Nordic commercialization rights and plans joint commercialization

Negative

• UK label remains limited to specified ApoE ε4 genotypes from prior approval
• Some patients may still require ongoing biweekly infusions, sustaining treatment burden

Insights

Regulatory and Commercial Analyst

MHRA approves intravenous maintenance dosing of Leqembi in the UK, expanding dosing flexibility after initial 18-month regimen.

Leqembi now has an MHRA label allowing transition to 10 mg/kg IV once every four weeks after 18 months of 10 mg/kg every two weeks, which changes the treatment rhythm and may reduce clinic visits and infusion burden for patients with early Alzheimer’s disease.

The commercial and clinical impact depends on rollout logistics, payer acceptance, and uptake among the estimated population where Alzheimer’s accounts for 60-70% of dementia cases; safety monitoring and eligibility rules such as ApoE ε4 status remain operational dependencies that will affect patient flow.

Watch for public reimbursement decisions and real-world prescribing patterns over the next 6–12 months, any local guidance on patient selection and monitoring, and joint commercialization steps between BioArctic and Eisai in the Nordic region; these milestones will clarify revenue timing and healthcare operational impact.

STOCKHOLM, Nov. 13, 2025 /PRNewswire/ -- BioArctic AB's (publ) (Nasdaq Stockholm: BIOA B) partner Eisai announced today that Leqembi (lecanemab) has been approved for once every four weeks intravenous (IV) maintenance dosing for the treatment of early Alzheimer's disease by the Medicines and Healthcare products Regulatory Agency (MHRA) in the United Kingdom.

In August 2024, Leqembi was approved for the treatment of mild cognitive impairment (MCI) and mild dementia due to Alzheimer's disease (AD) in adult patients that are apolipoprotein E ε4 (ApoE ε4)^[1] heterozygotes or non-carriers in the United Kingdom. With this latest approval for IV maintenance dosing, after 18 months of a dosing regimen of 10 mg/kg once every two weeks, patients may be transitioned to a maintenance dosing regimen of 10 mg/kg once every four weeks, or they may continue with 10 mg/kg once every two weeks .

In the United Kingdom, an estimated 982,000 people are living with dementia,^[2] with AD accounting for an estimated 60-70% of cases.^[3] These numbers are expected to rise as the population ages.

Leqembi is the result of a long-standing collaboration between BioArctic and Eisai, and the antibody was originally developed by BioArctic based on the work of Professor Lars Lannfelt and his discovery of the Arctic mutation in Alzheimer's disease. Eisai is responsible for the clinical development, applications for market approval and commercialization of Leqembi for Alzheimer's disease. BioArctic has the right to commercialize Leqembi in the Nordic region together with Eisai and the two companies are preparing for a joint commercialization in the region.

The information was released for public disclosure, through the agency of the contact person below, on November 14, 2025, at 00:30 a.m. CET.

For further information, please contact: 
Oskar Bosson, VP Communications and Investor Relations
E-mail: oskar.bosson@bioarctic.com 
Telephone: +46 704 107 180

About lecanemab (Leqembi ^® )
Lecanemab is the result of a strategic research alliance between BioArctic and Eisai. It is a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ).

Lecanemab is approved in 51 countries including the U.S., Japan, China, and the European Union for the treatment of Alzheimer's disease (AD) in patients with Mild Cognitive Impairment (MCI) or mild dementia stage of disease (collectively referred to as early AD) and is under regulatory review in 9 countries. Following the initial phase with treatment every two weeks for 18 months, intravenous (IV) maintenance dosing with treatment every four weeks is approved in the United Kingdom, China, the U.S. and others, and applications have been filed in 4 countries and regions.

Leqembi's approvals in these countries were based on Phase 3 data from Eisai's, global Clarity AD clinical trial, in which it met its primary endpoint and all key secondary endpoints with statistically significant results. The primary endpoint was the global cognitive and functional scale, Clinical Dementia Rating Sum of Boxes (CDR-SB).^[4] Leqembi Iqlik™ is approved for subcutaneous dosing with an autoinjector for maintenance treatment of early Alzheimer's disease in the US. In September 2025, a rolling sBLA application for the subcutaneous initiation dosing with Leqembi Iqlik was also initiated to the U.S. FDA.

Since July 2020, Eisai's Phase 3 clinical study (AHEAD 3-45) with lecanemab in individuals with preclinical AD, meaning they are clinically normal and have intermediate or elevated levels of amyloid in their brains, is ongoing. The study was fully recruited in October 2024. AHEAD 3-45 is a four-year study conducted as a public-private partnership between Eisai, Biogen and the Alzheimer's Clinical Trial Consortium that provides the infrastructure for academic clinical trials in AD and related dementias in the U.S, funded by the National Institute on Aging, part of the National Institutes of Health. Since January 2022, the Tau NexGen clinical study for Dominantly Inherited AD (DIAD), that is conducted by Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU), led by Washington University School of Medicine in St. Louis, is ongoing and includes lecanemab as the backbone anti-amyloid therapy.

About the collaboration between BioArctic and Eisai
Since 2005, BioArctic has a long-term collaboration with Eisai regarding the development and commercialization of drugs for the treatment of Alzheimer's disease. The most important agreements are the Development and Commercialization Agreement for the lecanemab antibody, which was signed 2007, and the Development and Commercialization agreement for the antibody Leqembi back-up for Alzheimer's disease, which was signed 2015. In 2014, Eisai and Biogen entered into a joint development and commercialization agreement for lecanemab. Eisai is responsible for the clinical development, application for market approval and commercialization of the products for Alzheimer's disease. BioArctic has the right to commercialize lecanemab in the Nordic region and is currently preparing for commercialization in the Nordics together with Eisai. BioArctic has no development costs for lecanemab in Alzheimer's disease and is entitled to payments in connection with sales milestones as well as royalties on global sales.

About BioArctic AB
BioArctic AB (publ) is a Swedish research-based biopharma company focusing on innovative treatments that can delay or stop the progression of neurodegenerative diseases. The company invented Leqembi® (lecanemab) – the world's first drug proven to slow the progression of the disease and reduce cognitive impairment in early Alzheimer's disease. Leqembi has been developed together with BioArctic's partner Eisai, who are responsible for regulatory interactions and commercialization globally. In addition to Leqembi, BioArctic has a broad research portfolio with antibodies against Parkinson's disease and ALS as well as additional projects against Alzheimer's disease. Several of the projects utilize the company's proprietary BrainTransporter™ technology, which has the potential to actively transport antibodies across the blood-brain barrier to enhance the efficacy of the treatment. BioArctic's B share (BIOA B) is listed on Nasdaq Stockholm Large Cap. For further information, please visit www.bioarctic.com.

^[1] Apolipoprotein E is a protein involved in the metabolism of lipid in humans. It is implicated in AD. People with only one (heterozygous) or no copy (non-carriers) of the ApoE ε4 gene are less likely to experience ARIA than people with two ApoE ε4 copies (homozygous).

^[2] Alzheimer's Society. 2024. The economic impact of dementia. Available at: https://www.alzheimers.org.uk/about-us/policy-and-influencing/dementia-scale-impact-numbers. Last accessed: August 2024.

^[3] World Health Organization. 2023. Dementia. Available at: https://www.who.int/news-room/fact-sheets/detail/dementia. Last accessed: August 2024

^[4] Eisai presents full results of lecanemab Phase 3 confirmatory Clarity AD study for early Alzheimer's disease at Clinical Trials on Alzheimer's Disease (CTAD) conference. Available at: https://www.eisai.co.jp/news/2022/news202285.html 

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Leqembi® approved for IV maintenance treatment in the United Kingdom

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SOURCE BioArctic

FAQ

What did BioArctic/Eisai announce about Leqembi (B) in the UK on November 14, 2025?

Eisai received MHRA approval for Leqembi IV maintenance dosing every four weeks after an 18-month induction period.

Who is eligible for Leqembi treatment under the UK approvals for symbol B?

The UK approvals cover adults with early Alzheimer’s disease; the prior August 2024 approval specified ApoE ε4 heterozygotes and non-carriers.

What is the approved Leqembi dosing regimen change announced for the UK (B)?

After 18 months at 10 mg/kg every two weeks, patients may switch to 10 mg/kg every four weeks or continue biweekly dosing.

How does the Leqembi UK approval affect BioArctic’s commercial rights (B)?

BioArctic retains the right to commercialize Leqembi in the Nordic region and is preparing joint commercialization with Eisai.

When was Leqembi previously approved in the UK before the November 14, 2025 update for B?

Leqembi was previously approved in the UK in August 2024 for MCI and mild dementia due to Alzheimer’s in certain ApoE ε4 genotypes.