Eisai-Biogen Alzheimer’s Drug Shows Amyloid Reduction, Disease-Modifying Effect 

Eisai and Biogen today announced positive updates on the Phase IIB 201 and open-label extension (OLE) studies they are conducting on the use of lecanemab to treat early Alzheimer’s Disease (AD).

Their latest findings reflected new clinical, biomarker and safety assessments of brain amyloid reduction while using the drug. The OLE showed a clinical benefit in reducing brain amyloid levels in as early as three months and significant clearance in over 80% of the participants by months 12 to 18, as measured using a visual PET reading. The study has a duration of five years.

Eisai and Biogen entered into a joint development and commercialization agreement for lecanemab in October 2017. They are currently conducting a Phase III clinical study (Clarity AD) in patients with symptomatic early AD, following promising results from their Phase II trials (Study 201). The Phase III clinical study (Ahead 3-45) for persons with preclinical AD started in July 2020. Preclinical AD refers to people who are clinically normal but have intermediate or elevated amyloid levels in the brain.

The most recent assessment showed consistency with core phase (Study 201) results, which went on for 18 months. During the OLE, patients received 10 mg/kg of lecanemab via IV biweekly with an intervening gap period of nine to 59 months (mean 24 months) where they did not receive any treatment.

The study found a treatment difference of only 0.10 between those who continued lecanemab and those who went into a gap period and restarted the drug, as measured through biomarkers, amyloid PET, plasma Aβ 42/40 and p-tau181. This suggests that lecanemab may have a disease-modifying effect. Plasma Aβ 42/40 and Plasma p-tau181 are two new blood tests (plasma biomarkers) that can be used to monitor treatment effects alongside PET.

“The latest lecanemab findings provide greater insight into the time course and extent of amyloid reduction observed with lecanemab, and the relationship to clinical outcomes and blood-based biomarkers. The Clarity AD Phase 3 Study in Early AD, which completed enrollment of 1795 subjects in March, aims to verify these findings,” Dr. Lynn Kramer, M.D., chief clinical officer for the Neurology Business Group at Eisai, said in a statement.

The results were presented in a late-breaking roundtable session at the 2021 Clinical Trials on Alzheimer’s Disease conference, which is ongoing from November 9 to 12 in Boston, Massachusetts and online. Eisai has already started its submission for a Biologics License Application (BLA) for the drug to the U.S. Food and Drug Administration via accelerated approval.