New data on long-term, real-world treatment with lecanemab presented at the 2026 AD/PD™ congress

Rhea-AI Summary

BioArctic (NASDAQ: B) reported new data presented at AD/PD 2026 on long-term, real-world IV lecanemab treatment persistence and additional company presentations. Real-world claims analysis showed 78.4% persistence at 18 months, 71.7% at 20 months and 67.3% at 24 months. BioArctic also presented data on lecanemab binding to soluble Aβ protofibrils and a poster on exidavnemab trial screening using alpha-synuclein SAA. The release notes investigational status and no guarantee of regulatory approval.

Positive

• 78.4% lecanemab persistence at 18 months in real-world US data
• 71.7% persistence at 20 months and 67.3% at 24 months showing multi-year continuity
• 94% of Clarity AD completers elected OLE maintenance treatment
• BioArctic data show lecanemab selectively targets soluble Aβ protofibrils
• Exidavnemab screening used alpha-synuclein SAA to balance trial arms

Negative

• Real-world persistence declined to 67.3% by 24 months
• Results describe investigational use; no guarantee of regulatory approval

News Market Reaction – BIOA

-3.47%

50 alerts

-3.47% News Effect

-21.6% Trough in 5 hr 43 min

-$28M Valuation Impact

$778M Market Cap

0.8x Rel. Volume

On the day this news was published, BIOA declined 3.47%, reflecting a moderate negative market reaction. Argus tracked a trough of -21.6% from its starting point during tracking. Our momentum scanner triggered 50 alerts that day, indicating high trading interest and price volatility. This price movement removed approximately $28M from the company's valuation, bringing the market cap to $778M at that time.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

Treatment persistence 18m: 78.4% of individuals Treatment persistence 20m: 71.7% of individuals Treatment persistence 24m: 67.3% of individuals +5 more

8 metrics

Treatment persistence 18m 78.4% of individuals Real-world IV lecanemab users continuing after 18 months

Treatment persistence 20m 71.7% of individuals Real-world IV lecanemab users continuing after 20 months

Treatment persistence 24m 67.3% of individuals Real-world IV lecanemab users continuing after 24 months

Clarity AD continuation 94% of patients Phase 3 Clarity AD completers choosing to enter OLE

Initial treatment period 18 months Baseline treatment duration before assessing persistence

Long-term treatment Four years Duration patients benefited from lecanemab in OLE vs natural history

AD/PD conference dates March 17–21, 2026 Timing of AD/PD congress where data were presented

Conference year 2026 International Conference on Alzheimer’s and Parkinson’s Diseases

Market Reality Check

Price: $16.11 Vol: Volume 1,734,534 is 3.07x...

high vol

$16.11 Last Close

Volume Volume 1,734,534 is 3.07x the 20-day average of 565,025, indicating elevated trading activity before this release. high

Technical Price at $19.30 is trading above the 200-day MA of $10.02, though still 19.58% below the 52-week high of $24.00.

Peers on Argus

BIOA fell 8.27% with elevated volume, while peers like CTOR (-8.22%), SXTC (-7.2...

BIOA fell 8.27% with elevated volume, while peers like CTOR (-8.22%), SXTC (-7.28%), IRWD (-5.00%) and DERM (-4.88%) also declined, pointing to broader sector weakness alongside company-specific news.

Historical Context

5 past events · Latest: Feb 27 (Neutral)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Feb 27	Share count update	Neutral	-0.2%	Updated total shares and votes outstanding after option program issuance.
Feb 19	Conference appearance	Neutral	+1.8%	Announcement of participation and fireside chat at healthcare conference.
Feb 11	Earnings invitation	Neutral	-1.0%	Invitation to Q4 2025 report presentation and investor webcast.
Feb 06	Leqembi sales update	Positive	+3.8%	Reported Q4 2025 Leqembi sales and higher SEK royalty versus prior year.
Jan 21	Equity offering	Negative	-6.1%	Upsized $115M public equity offering under existing shelf registration.

Pattern Detected

Recent news typically led to modest moves that largely aligned with the tone: positive commercial updates and dilutive offerings saw directional price alignment, while routine corporate updates had small reactions.

Recent Company History

Over the past few months, BIOA-related names have issued a mix of corporate updates and financing. A January $115.0M public offering was followed by a -6.06% move, while a February update highlighting Leqembi Q4 2025 sales of JPY 20.7 billion and a royalty of SEK 127M coincided with a 3.75% gain. Routine items like share-count notices and event invitations produced small reactions. Today’s real‑world lecanemab data fits the stream of Alzheimer’s franchise updates but preceded a notably larger price move.

Regulatory & Risk Context

Active S-3 Shelf

Shelf Active

Active S-3 Shelf Registration 2025-11-05

An amended Form S-3/A filed on 2025-11-05 registers the resale of up to 2,227,124 existing BIOA shares by a selling stockholder. The company is not selling shares and will not receive proceeds from these resales. The shelf has seen 2 recent 424B5 usages, and the amendment is not yet effective.

Market Pulse Summary

This announcement highlights encouraging real‑world lecanemab persistence, with 78.4% of patients re...

Analysis

This announcement highlights encouraging real‑world lecanemab persistence, with 78.4% of patients remaining on therapy at 18 months and 67.3% at 24 months, and notes that 94% of Clarity AD completers entered the long‑term extension. It also showcases BioArctic’s mechanistic work and exidavnemab trial design. Investors may track future updates on durability beyond four years, regulatory milestones, and how these data translate into commercial performance and partnering economics.

Key Terms

intravenous (iv), open-label, protofibrils, alpha-synuclein, +3 more

7 terms

intravenous (iv) medical

"patients in the United States receiving intravenous (IV) lecanemab."

A method of delivering fluids, medicines or nutrients directly into a vein through a needle or tube so they enter the bloodstream immediately, like sending a package straight to the main highway instead of along side roads. Investors care because intravenous delivery affects how fast and reliably a treatment works, the complexity and cost of products and devices, hospital and clinic use, regulatory scrutiny and reimbursement — all of which influence commercial value.

open-label medical

"by enrolling in the subsequent open-label, long-term extension (OLE) study."

Open-label describes a situation where everyone involved in a study or process knows the full details, such as who is receiving a treatment or intervention. For investors, understanding whether a project or product is open-label helps gauge the level of transparency and potential biases, influencing trust and decision-making. It’s like knowing whether a test or experiment is conducted openly or behind closed doors.

protofibrils medical

"selective targeting of soluble amyloid-beta (Aβ) protofibrils."

Protofibrils are tiny, thread-like structures that form part of larger protein assemblies in the body, often associated with the buildup of harmful substances. They are important to investors because their formation can indicate underlying health issues or biological processes that may impact pharmaceutical companies or medical research, influencing market trends and investment decisions. Understanding protofibrils helps in assessing the significance of advancements or setbacks in related healthcare fields.

alpha-synuclein medical

"applying alpha-synuclein seed amplification assay (SAA) for patient stratification"

A small brain protein that helps nerve cells function, which can misfold and clump together in certain neurodegenerative diseases. Investors care because these clumps are both a target for new therapies and a potential marker used in clinical trials and diagnostics; success or failure of drugs aimed at alpha-synuclein can strongly affect a developer’s clinical prospects, regulatory chances, and market value. Think of it as a faulty part in a machine that companies try to repair or remove.

seed amplification assay (saa) medical

"applying alpha-synuclein seed amplification assay (SAA) for patient stratification"

A seed amplification assay (SAA) is a laboratory test that detects tiny amounts of misfolded proteins associated with neurodegenerative diseases by encouraging those abnormal proteins to copy themselves until they can be measured, similar to watching a single spark grow into a visible flame. For investors, SAAs matter because they can enable earlier and more reliable diagnosis, support clinical trials by confirming target engagement, and create commercial opportunities for diagnostic tools tied to disease-modifying therapies.

multiple system atrophy medical

"trial in Parkinson's disease and multiple system atrophy (EXIST)"

A progressive neurological disorder that damages multiple areas of the nervous system, causing problems with movement, balance and involuntary functions like blood pressure and bladder control; think of it as critical wiring in the body slowly failing. Investors care because the condition defines the size and urgency of the market for treatments, influences clinical trial difficulty and regulatory risk, and can lead to high per-patient pricing but also greater development uncertainty.

randomization medical

"between arms while still allowing timely randomization."

Randomization is the process of assigning participants in a clinical study to different treatment groups by chance—like flipping a coin or drawing names from a hat—rather than by choice. That impartial assignment reduces bias and makes it more likely that differences in outcomes come from the treatments themselves, so investors can trust trial results as stronger evidence of a drug’s or device’s effectiveness and safety.

AI-generated analysis. Not financial advice.

STOCKHOLM, March 23, 2026 /PRNewswire/ -- BioArctic's AB (publ) (NASDAQ: BIOA B) partner Eisai presented new data at the 2026 International Conference on Alzheimer's and Parkinson's Diseases and related neurological disorders (AD/PD™), held in Copenhagen, Denmark March 17-21. BioArctic also held an oral presentation on lecanemab and a poster presentation relating to exidavnemab.  

Eisai presented new real-world findings from an analysis of long-term treatment persistence among early Alzheimer's disease patients in the United States receiving intravenous (IV) lecanemab. Based on data from the PurpleLab®^[1] claims database, the analysis showed that most patients continued lecanemab therapy after the initial 18 months of treatment (78.4% of individuals continued lecanemab treatment at 18 months, 71.7% at 20 months, and 67.3% at 24 months).

In real-world clinical practice, patients with chronic diseases who stay on their treatments longer tend to experience better clinical outcomes.^[2],[3] The results are similar to what was seen in the Phase 3 Clarity AD study where 94% of patients who completed 18 months of lecanemab treatment chose to continue maintenance treatment by enrolling in the subsequent open-label, long-term extension (OLE) study. In the OLE study, patients who stayed on treatment continued to benefit from four years of lecanemab treatment compared with the natural course of Alzheimer's disease (ADNI^[4]).

BioArctic's presentations
Professor Lars Lannfelt, BioArctic's co-founder, delivered an oral presentation about the binding profile of lecanemab in Alzheimer's disease brain tissue, demonstrating its selective targeting of soluble amyloid-beta (Aβ) protofibrils. He described the mechanisms of action, showing how lecanemab engages immune pathways to promote clearance of Aβ.

Ebba Amandius from BioArctic also presented a poster that showed the successful use of a screening strategy in the ongoing exidavnemab trial in Parkinson's disease and multiple system atrophy (EXIST), applying alpha-synuclein seed amplification assay (SAA) for patient stratification between placebo and treatment arms. The approach enabled even distribution of participants with alpha-synuclein pathology between arms while still allowing timely randomization. It highlights the feasibility and importance of SAA testing during screening in clinical trials targeting alpha-synuclein. The poster can be found on BioArctic's website.

Lecanemab 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 Lannfelt and his discovery of the Arctic mutation in Alzheimer's disease.

This release discusses investigational uses of an agent in development and is not intended to convey conclusions about efficacy or safety. There is no guarantee that such investigational agents will successfully complete clinical development or gain health authority approval.

The information was released for public disclosure, through the agency of the contact persons below, on March 23, 2026, at 08:30 CET.

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

Jenny Ljunggren, External Communications and Investor Relations Manager
E-mail: jenny.ljunggren@bioarctic.com
Telephone: +46 76 013 86 08

About Leqembi^® (lecanemab)
Leqembi 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).

Leqembi is approved in 53 countries and is under regulatory review in 6 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 7 countries, including the United Kingdom, China, the US and Japan, and applications have been filed in 10 countries and regions. In the US, Leqembi Iqlik™ is approved for subcutaneous dosing with an autoinjector for maintenance treatment of early Alzheimer's disease. In November 2025, a new drug application for subcutaneous formulation of Leqembi was submitted in Japan. In December 2025, Leqembi was included in the "Commercial Insurance Innovative Drug List", recently introduced by the National Healthcare Security Administration (NHSA) of China. In January 2026, Eisai's supplemental Biologics License Application regarding a subcutaneous starting dose with Leqembi Iqlik was granted Priority Review by the US FDA with a May 24, 2026, PDUFA date. In January 2026, the Biologics License Application for subcutaneous formulation of Leqembi was accepted in China and in February, the application was designated for priority review.

Since July 2020, Eisai's Phase 3 clinical study (AHEAD 3-45) with lecanemab in individuals with preclinical Alzheimer's disease 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 Alzheimer's disease and related dementias in the US, 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 Alzheimer's disease (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 lecanemab 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] The PurpleLab® CLEAR Claims database, is a comprehensive dataset based on medical insurance claims across the United States and was used to evaluate the long-term treatment persistence of lecanemab in real-world clinical practice.

^[2] Guerci B et al. Lack of treatment persistence and treatment nonadherence as barriers to glycaemic control in patients with type 2 diabetes. Diabetes Therapy, 2019; 10(2), 437-449.

^[3] Menditto E et al. Persistence as a robust indicator of medication adherence-related quality and performance. International journal of environmental research and public health, 2021; 18(9), 4872.

^[4] Alzheimer's Disease Neuroimaging Initiative.  

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New data on long-term, real-world treatment with lecanemab presented at the 2026 AD/PDâ„¢ congress

 

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SOURCE BioArctic

FAQ

What were the lecanemab real-world treatment persistence rates reported by BioArctic (B) at AD/PD 2026?

Most patients remained on IV lecanemab: 78.4% at 18 months, 71.7% at 20 months, 67.3% at 24 months. According to BioArctic, these figures come from a PurpleLab claims analysis of US early Alzheimer’s patients.

How do AD/PD 2026 lecanemab persistence findings compare with the Clarity AD trial for BioArctic (B)?

Persistence patterns are broadly similar: Clarity AD showed 94% of 18-month completers chose OLE maintenance. According to BioArctic, OLE data suggested continued benefit versus the natural course over four years.

What mechanistic data on lecanemab did BioArctic (B) present at AD/PD 2026?

An oral presentation showed lecanemab selectively binds soluble Aβ protofibrils and engages immune pathways to promote Aβ clearance. According to BioArctic, this supports the antibody’s proposed mechanism of action in Alzheimer’s disease.

What did BioArctic report about exidavnemab trial screening at AD/PD 2026?

A poster described using alpha-synuclein SAA for patient stratification, enabling even distribution between placebo and treatment arms. According to BioArctic, the approach improved randomization feasibility in the EXIST Parkinson’s/MST trial.

Does BioArctic (B) say lecanemab is approved based on the AD/PD 2026 presentation?

No, the release clarifies lecanemab use discussed is investigational and not a conclusion on efficacy or safety. According to BioArctic, there is no guarantee investigational agents will gain health authority approval.