What did the real-world data reveal about lecanemab (LEQEMBI®) treatment persistence?

A large-scale U.S. claims analysis of 10,763 patients showed that 67.3% of individuals remained on lecanemab therapy at the 24-month mark. This high level of adherence suggests that the bi-weekly intravenous (IV) infusion schedule and monitoring requirements are not acting as significant barriers to long-term treatment. For investors, this data is a key "bull" point, as high persistence rates translate to more predictable, recurring revenue per patient.

How does this real-world evidence compare to clinical trial results?

The real-world persistence rates—78.4% at 18 months and 67.3% at 24 months—closely mirror the high continuation seen in the pivotal Phase 3 Clarity AD trials. In those trials, 94% of patients who completed the initial 18-month period chose to enter the long-term extension study. The fact that real-world performance is matching controlled clinical settings reduces the "implementation risk" for the drug's commercial rollout.

What is the logistical burden for patients on lecanemab, and are they sticking to it?

Despite requiring bi-weekly infusions and regular MRI scans to monitor for potential side effects like ARIA (amyloid-related imaging abnormalities), the mean dosing interval was found to be 16.4 days. This indicates that most patients are staying very close to the recommended 14-day schedule. High adherence in a "real-world" setting suggests that the clinical benefit is perceived by patients and caregivers to outweigh the logistical challenges.

Why is lecanemab’s "binding profile" considered a core differentiator?

Lecanemab is highly selective for soluble amyloid-beta (Aβ) protofibrils, which research suggests are the most toxic forms of the protein responsible for damaging neurons. By targeting these protofibrils over monomers (single proteins) or insoluble fibrils (plaques), the drug aims to neutralize the most harmful species while minimizing off-target effects. This scientific "moat" is what BioArctic and Eisai believe gives the drug its superior efficacy-to-safety ratio compared to competitors.

What is the latest update on BioArctic’s (NASDAQ:B) Parkinson’s drug, exidavnemab?

BioArctic presented new data from its ongoing EXIST Phase 2a trial, which is testing exidavnemab in patients with Parkinson’s disease and multiple system atrophy (MSA). The study successfully utilized an alpha-synuclein seed amplification assay (SAA) as a screening tool. This biomarker-driven approach ensures that the trial only enrolls patients who specifically have the misfolded protein pathology that the drug is designed to clear.

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BioArctic and Eisai showcase durable real-world persistence for lecanemab

Written by Jon CuthbertPublished Mar 23, 2026, 12:00 AMLast Updated Jul 6, 2026, 10:43 AM

BioArctic (NASDAQ:B) and its partner Eisai presented significant new data at the 2026 International Conference on Alzheimer’s and Parkinson’s Diseases (AD/PD™) in Copenhagen, highlighted by the first large-scale look at real-world long-term persistence for the Alzheimer's treatment lecanemab.

A claims analysis of 10,763 individuals in the United States showed that 78.4% of patients remained on the intravenous (IV) therapy at 18 months, with 71.7% persisting at 20 months and 67.3% continuing through 24 months.

The retrospective study, which utilized the PurpleLab CLEAR Claims database, indicates that real-world adherence is mirroring the high continuation rates seen in the pivotal Phase 3 Clarity AD clinical trials.

The data revealed a mean dosing interval of 16.4 days, suggesting that patients are largely sticking to the recommended bi-weekly infusion schedule despite the logistical requirements of MRI monitoring and clinical administration.

In addition to the persistence data, BioArctic’s co-founder Professor Lars Lannfelt delivered an oral presentation regarding lecanemab’s unique binding profile.

The research confirmed the antibody’s high selectivity for soluble amyloid-beta (Aβ) protofibrils—the species believed to be the most toxic to neurons—over monomers and fibrils.

This selectivity is a core differentiator for lecanemab and is thought to contribute to its efficacy in slowing cognitive decline while minimizing certain off-target risks.

BioArctic also provided updates on its proprietary pipeline, specifically a poster presentation on exidavnemab, a drug candidate for Parkinson's disease and multiple system atrophy.

The company showcased the successful use of an alpha-synuclein seed amplification assay (SAA) as a screening tool in the ongoing EXIST Phase 2a trial.

This biomarker-driven approach allows for more precise patient stratification, ensuring that participants have the specific protein pathology that exidavnemab is designed to target.

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BioArctic and Eisai showcase durable real-world persistence for lecanemab

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