Biogen and Eisai’s Alzheimer’s disease (AD) drug Leqembi (lecanemab) has shown continued benefit over four years, according to new phase 3 results presented at this year’s Alzheimer’s Association International Conference (AAIC).
The late-stage Clarity AD trial randomised patients with early AD to receive bi-weekly intravenous (IV) Leqembi or placebo over 18 months, and 95% of those who completed the study chose to continue in the open-label extension.
In the core study, the mean change from baseline between the Leqembi cohort and the placebo group after 18 months was -0.45 on the primary endpoint of Clinical Dementia Rating Sum of Boxes (CDR-SB) global cognitive and functional scale.
This grew over three and four years of treatment, with Leqembi reducing cognitive decline by 1.01 and 1.75 CDR-SB points, respectively, compared to the expected decline observed in the Alzheimer’s Disease Neuroimaging Initiative cohort.
The Clarity AD data presented at AAIC also showed that patients who started treatment with Leqembi in the earlier stages of AD continued to show improvement in clinical scores after four years.
Among those with low levels of tau accumulation in the brain, an indicator of early-stage AD, 69% demonstrated improvement or no decline, while 56% showed improvement from baseline on the CDR-SB after four years of Leqembi treatment.
AD is an irreversible and progressive neurodegenerative disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out simple tasks. The disease currently affects an estimated seven million people in the US, with this projected to rise to nearly 13 million by 2050.
Leqembi, which has already been approved in 46 countries, works by binding to and reducing clumps of amyloid beta protein that form plaques in the brain.
Beyond its IV formulation, Eisai and Biogen have an injectable version of the drug, which could reduce the need for hospital or infusion site visits and nursing care for IV administration.
The US Food and Drug Administration has accepted an application for the Leqembi subcutaneous autoinjector for weekly maintenance dosing and set a target review date of 31 August 2025.
Eisai serves as the lead for the drug’s development and regulatory submissions globally, with both partners co-commercialising and co-promoting the product and Eisai having final decision-making authority.