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

Market Reaction – B

-5.39% $35.14

15m delay 5 alerts

-5.39% Since News

$35.14 Last Price

$34.66 $38.41 Day Range

-$3.54B Valuation Impact

$62.22B Market Cap

68K Volume

Following this news, B has declined 5.39%, reflecting a notable negative market reaction. Our momentum scanner has triggered 5 alerts so far, indicating moderate trading interest and price volatility. The stock is currently trading at $35.14. This price movement has removed approximately $3.54B from the company's valuation.

Data tracked by StockTitan Argus (15 min delayed). Upgrade to Silver for real-time data.

Key Figures

Treatment persistence at 18 months: 78.4% Treatment persistence at 20 months: 71.7% Treatment persistence at 24 months: 67.3% +4 more

7 metrics

Treatment persistence at 18 months 78.4% Real-world IV lecanemab use in early Alzheimer’s disease

Treatment persistence at 20 months 71.7% Real-world IV lecanemab use in early Alzheimer’s disease

Treatment persistence at 24 months 67.3% Real-world IV lecanemab use in early Alzheimer’s disease

Initial treatment period 18 months Real-world persistence analysis threshold for lecanemab

Continuation in Clarity AD 94% Phase 3 Clarity AD patients opting into long-term extension

Long-term treatment duration 4 years Benefit in open-label extension vs. natural Alzheimer’s course

Conference dates March 17–21 AD/PD 2026 congress where lecanemab data were presented

Market Reality Check

Price: $37.12 Vol: Volume 15,183,035 vs 20-d...

normal vol

$37.12 Last Close

Volume Volume 15,183,035 vs 20-day average 14,729,405 (about 1.03x average) indicates typical trading activity pre-news. normal

Technical Shares at 37.12 are trading above the 200-day MA of 34.72, indicating a pre-news uptrend despite the recent pullback.

Peers on Argus

Gold peers like WPM (-6.02%), AU (-4.93%), FNV (-3.66%), AEM (-3.65%) and KGC (-...

Gold peers like WPM (-6.02%), AU (-4.93%), FNV (-3.66%), AEM (-3.65%) and KGC (-3.35%) were all down alongside the stock’s -2.98% move, but the momentum scanner did not flag a coordinated sector move.

Historical Context

5 past events · Latest: Mar 17 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Mar 17	Clinical trial approval	Positive	-0.7%	Regulatory approval to initiate Phase I PK study of CS014.
Mar 16	Strategic partnership	Positive	+0.8%	New partnership integrating validation tech into repair program.
Mar 10	Research publication	Neutral	+0.7%	Global study on public attitudes towards robots across markets.
Feb 27	Share count update	Neutral	+0.8%	Issuance of 78,000 Class B shares and updated votes total.
Feb 27	Annual filings	Neutral	+0.8%	Release of 2025 Annual Report and NI 43-101 technical reports.

Pattern Detected

Recent news shows a mix of aligned and divergent reactions: positive clinical progress and neutral corporate updates sometimes led to modest gains, while a positive trial update saw a slight decline.

Recent Company History

Over the last few months, news tied to ticker B has spanned clinical progress, partnerships, corporate updates and share structure changes. A March 17, 2026 Phase I PK study approval for CS014 and a March 16 strategic partnership were generally met with modest moves within +/-1%. Neutral items like share-count disclosures on Feb 27, 2026 and annual information filings also produced small positive or slightly divergent reactions, suggesting measured market responses to varied catalysts.

Market Pulse Summary

The stock is down -5.4% following this news. A negative reaction despite encouraging real-world leca...

Analysis

The stock is down -5.4% following this news. A negative reaction despite encouraging real-world lecanemab data would fit a pattern where even positive or neutral news around ticker B sometimes saw muted or mixed follow-through. The article itself notes that these are investigational uses without guaranteed approvals, which can temper sentiment. Any sharp downside could reflect market caution around development risk rather than the specific persistence figures like 78.4% at 18 months and 67.3% at 24 months.

Key Terms

intravenous (iv), phase 3, open-label, protofibrils, +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.

phase 3 medical

"similar to what was seen in the Phase 3 Clarity AD study where 94%"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

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

"demonstrating its 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.

placebo medical

"for patient stratification between placebo and treatment arms."

A placebo is an inactive pill, injection or procedure that looks and feels like the real treatment but contains no therapeutic ingredient, often called a sugar pill. Investors care because comparing a drug to a placebo reveals whether observed benefits come from the medicine itself or from expectation; clear superiority over placebo reduces regulatory and commercial risk, much like a blind taste test proves a new recipe really tastes better.

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.

seed amplification assay medical

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

A seed amplification assay is a laboratory test that detects tiny amounts of disease-linked misfolded proteins by encouraging them to multiply until they are measurable, much like coaxing a few embers to become a visible flame. For investors, it matters because these assays can enable earlier and more reliable diagnosis, speed clinical trials, and create commercial markets for diagnostic kits and companion tests, which can alter the value and risk of companies developing related therapies or diagnostics.

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.  

This information was brought to you by Cision http://news.cision.com

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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.