1. Lecanemab shows promise in early Alzheimer's treatment at AAIC 2025. 2. Study shows 87.4% patient retention on lecanemab after one year. 3. Real-world data indicates high efficacy and satisfaction with lecanemab. 4. Adverse events remain low, within FDA-approved ranges. 5. Eisai and Biogen's collaboration continues to drive lecanemab's market potential.
High patient retention and satisfaction suggests strong market performance. Historical parallels include breakthrough therapies like aducanumab that resulted in short-term stock surges.
The article highlights pivotal developments in a product that directly impacts Biogen's revenue potential, indicating significant relevance.
Pending further data and FDA actions can sustain long-term growth in stock value. The final report in 2026 could provide conclusive efficacy evidence supporting prolonged business confidence.
/PRNewswire/ -- Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, "Eisai") and Biogen Inc. (Nasdaq: BIIB, Corporate headquarters: Cambridge, Massachusetts, CEO: Christopher A. Viehbacher, "Biogen") announced today that the two-year real-world study in the U.S. of lecanemab (generic name, product name: LEQEMBI®), an anti-Aβ protofibril* antibody, was presented at the Alzheimer's Association International Conference (AAIC) 2025, held in Toronto, Canada and virtually. Only lecanemab fights AD in two ways – targeting both amyloid plaque and protofibrils*, which can impact tau downstream.
Lecanemab received traditional approval in the U.S. in July 2023 for the treatment of early Alzheimer's disease (AD). This retrospective study was conducted to investigate the actual state of real-world clinical treatment with lecanemab at 15 medical centers in the U.S., with a final report scheduled for late in the third quarter of Eisai's fiscal year ending March 31, 2026. This presentation serves as an interim report as of July 1, 2025.
The interim study collected information on 178 people living with early AD from nine U.S. medical centers using a standardized case report format. The disease stage of the patients at baseline was mild cognitive impairment (MCI) due to AD in 57.6% and mild AD in 42.4%. The average age of the patients was 74.2 (±6.6) years, and the ratio of men to women was 44.6 to 55.4.
The mean duration of lecanemab treatment was 375.4 days (± 182.8 days). The mean time from diagnosis to first treatment was 224.2 days (± 295.4 days) and the mean number of lecanemab treatments was 24.8 (± 11.5). At the time of case reporting, 87.4% of patients (152 patients) were continuing treatment with lecanemab. Adverse events leading to discontinuation of treatment included:
In 83.6% of patients who participated in this study, clinical stage remained at the same disease stage, or clinical stage improved from mild dementia to MCI (stable: 76.9%, improvement: 6.7%). Additionally, 86.7% of patients who received 40 or more doses (over 18 months), at time of interim data cut remained stable or clinically improved (stable: 66.7%, improvement: 20.0%).
Of the 178 patients, ARIA was observed in 23 (12.9%). 14 (7.9%) were observed to have ARIA-E, of which 12 (6.7%) were asymptomatic. ARIA-H was present in 11 patients (6.2%), all of whom were asymptomatic. Infusion reactions were observed in four patients (2.2%). Additionally, no serious bleeding events or deaths were reported.
Of the 178 patients in this study, 12 were excluded with unknown status. Among the remaining 166 patients:
Generally, the proportion of homozygotes among people with AD is thought to be 15% or more.
The incidence of ARIA was 20.0%, 9.8% and 14.8% in homozygous carriers, heterozygous carriers and non-carriers, respectively (45.0%, 19.0% and 13.0% respectively in the Phase 3 Clarity AD 18-month core study). The incidence rate of ARIA-E and ARIA-H were 13.3% and 10.0%, respectively (32.6% and 39.0% in the Clarity AD core study), which is within the FDA-approved label range. The majority of ARIA cases (0.13%) were asymptomatic. The incidence of adverse events leading to discontinuation was 16.7% in homozygous carriers, 2.4% in heterozygous carriers, and 5.6% in non-carriers.
73.3% of homozygote patients' clinical stage remained stable or improved (stable: 66.6%, improved: 6.7%), 88.0% of heterozygotes patients' clinical stage remained stable or improved (stable: 83.0%, improved: 4.9%) and 85.2% of non-carrier patients' clinical stage remained stable or improved (stable: 75.9%, improved: 9.3%).
BBMs are being developed in AD to identify brain Aβ pathology and are intended for use in prescreening (triage) and confirmatory diagnosis. Of the 178 patients in this study, 49 patients (27.5%) were diagnosed using BBMs. In some of these cases (11 patients, 6.1%), it was also used for confirmatory diagnosis. Data collected from clinical practices showed the volume of tests doubling every 4 to 8 months, with BBMs using p-tau217 growing most rapidly.
The results of a physician, patient and care partner lecanemab satisfaction survey was presented. The survey was based on questionnaires and interviews with nine U.S. physicians and evaluated treatment from multiple perspectives, including efficacy, safety and quality of life (QoL).
In the physicians' evaluation, the average satisfaction level for the treatment efficacy and safety (out of 10) was 8.7. The scoring criteria included:
The satisfaction level of the patients as assessed by physicians was 8.8, and that of the care partners was 8.2. These results reflect the high evaluation of the efficacy and safety of lecanemab in real-world clinical practice and support the value of lecanemab.
Retrospective real-world studies can be very valuable in providing additional information to complement clinical trial data. However, there may have several limitations to keep in mind:
Eisai serves as the lead for lecanemab's development and regulatory submissions globally with both companies co-commercializing and co-promoting the product and Eisai having final decision-making authority.
* Protofibrils are thought to be the most toxic Aβ species that contribute to brain damage in AD and play a major role in the cognitive decline of this progressive and devastating disease. Protofibrils can cause neuronal and synaptic damage in the brain, which can subsequently adversely affect cognitive function through multiple mechanisms. It is believed that reducing protofibrils may reduce neuronal damage and cognitive impairment, potentially preventing the progression of AD.
Eisai Co., Ltd.
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Eisai Inc. (U.S.)
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Biogen Inc.
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Eisai Co., Ltd.
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Biogen Inc.
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Lecanemab is the result of a strategic research alliance between Eisai and BioArctic. It is a humanized immunoglobulin gamma (IgG1) monoclonal antibody directed against aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). Protofibrils are believed to contribute to the brain injury that occurs with AD and are considered to be the most toxic form of Aβ, having a primary role in the cognitive decline associated with this progressive, debilitating condition.
Eisai and Biogen have been collaborating on the joint development and commercialization of AD treatments since 2014. Eisai serves as the lead of lecanemab development and regulatory submissions globally, with both companies co-commercializing and co-promoting the product and Eisai having final decision-making authority.
Since 2005, Eisai and BioArctic have had a long-term collaboration regarding the development and commercialization of AD treatments.
Eisai's Corporate Concept is "to give first thought to patients and people in the daily living domain, and to increase the benefits that health care provides."
Founded in 1978, Biogen is a leading biotechnology company that pioneers innovative science to deliver new medicines to transform patient's lives.
This news release contains forward-looking statements, including about the potential clinical effects of lecanemab; the potential benefits, safety and efficacy of lecanemab; potential regulatory discussions, submissions and approvals; and risks associated with drug development and commercialization.