Lecanemab CTAD data suggest early start and long-term use enhance benefits with consistent safety

STOCKHOLM, Oct. 31, 2024 /PRNewswire/ -- BioArctic AB's (publ) (NASDAQ Stockholm: BIOA B) partner Eisai shared recent insights on lecanemab (Leqembi®) at the Clinical Trials on Alzheimer's Disease (CTAD) congress, held in Madrid and virtually from October 29 to November 1. According to three-year data, lecanemab continues to provide significant benefits for patients with early Alzheimer's disease, showing improvements of approximately 1 point on the CDR-SB scale compared to the ADNI population, while maintaining a consistent safety profile. Furthermore, 46% of patients who began treatment with low levels of brain amyloid displayed either maintained or improved cognition and function after three years.

Key takeaways from the CTAD presentations include:

**Ongoing Benefits of Lecanemab in Early Alzheimer's Patients:**
Results from an open-label long-term extension study following the core phase 3 Clarity AD study revealed that, at 18 months, the mean change from baseline in the CDR-SB for the lecanemab group was -0.45 compared to the placebo group. By 36 months, this difference had expanded to -0.95 versus the ADNI population. The data also indicated a 30% reduced risk of disease progression. Additionally, a tau PET substudy showed that after three years of continuous treatment, 59% of patients with no or low tau accumulation at baseline exhibited either improvement or no decline, with 51% showing improvement from baseline on the CDR-SB.

Further data presented at CTAD highlighted that 46% of patients with low amyloid levels at baseline improved or had no decline on the CDR-SB after three years, with 33% showing improvement from baseline. Similar results were seen on the ADAS-Cog14 and ADCS MCI-ADL scales. These findings suggest that early initiation of lecanemab treatment might positively influence disease progression in early Alzheimer's patients, offering long-term benefits.

**Safety Profile:**
No new safety concerns emerged over three years of treatment with lecanemab. Most amyloid-related imaging abnormalities (ARIA) occurred within the first six months of treatment, with rates declining and stabilizing thereafter, similar to placebo rates. The incidence of ARIA was higher among ApoE4 homozygotes in comparison to heterozygotes or non-carriers, but new cases of ARIA decreased after 18 months of continuous treatment, regardless of ApoE4 status.

**Continued Treatment Benefits:**
The data indicated that Alzheimer's disease progresses when treatment ceases, suggesting that ongoing treatment after plaque clearance continues to yield positive effects. Clinical data and biomarkers, such as Aβ42/40 ratio, pTau181, pTau217, and GFAP, emphasized that remaining on treatment could prevent brain amyloid reaccumulation and deterioration of plasma biomarkers.

**Enhanced Efficacy in Great Britain:**
In Great Britain, ApoE4 heterozygotes or non-carriers exhibited a greater slowing of CDR-SB decline at 33% compared to the 27% observed in the total study population. Additionally, the rate of ARIA-E side effects was lower at 8.9% compared to 12.6% for the overall population.

**Progress in AHEAD 3-45 Study:**
The AHEAD 3-45 study, a four-year phase 3 trial for individuals with preclinical Alzheimer's disease, completed patient enrollment in October 2024. This study aims to evaluate patients with intermediate or elevated amyloid levels in the brain, determined by amyloid PET. Blood biomarker tests, especially plasma p-tau217, played a crucial role in improving eligibility for amyloid PET testing, reducing the screening failure rate from over 70% to below 30%.

**Statements from BioArctic:**
Gunilla Osswald, CEO at BioArctic, praised the long-term data presented by Eisai, stating that the continued patient benefits align with expectations for disease-modifying treatments. She highlighted the encouraging results for patients with early Alzheimer's disease from the low amyloid and no tau/low tau populations, suggesting that early initiation of lecanemab could significantly impact disease progression and offer sustained benefits.

Lecanemab is a product of the collaboration between BioArctic and Eisai, with BioArctic responsible for its initial development based on research by Professor Lars Lannfelt. Eisai oversees the clinical development, market approval applications, and global commercialization of lecanemab for Alzheimer's disease. BioArctic retains the right to commercialize lecanemab in the Nordic region and is preparing for joint commercialization with Eisai pending European approval.