On 25 October, Eisai presented new data on lecanemab during a late breaking symposium at the Clinical Trials on Alzheimer’s Disease (CTAD) conference held on October 24-27 in Boston. In July 2023, the US Food and Drug Administration (FDA) has granted traditional approval to lecanemab for the treatment of early Alzheimer’s disease (AD). The approval was based on positive results from the CLARITY-AD Phase III clinical trial, which enrolled 1,795 participants who received either lecanemab or a placebo biweekly via intravenous infusion. The trial showed a 27% reduction in clinical decline for participants receiving lecanemab.
Eisai showed results from a new novel subcutaneous form of lecanemab. Weekly subcutaneous administration of lecanemab resulted in greater (14%) amyloid plaque removal than biweekly intravenous administration. These results are based on a preliminary analysis from a subgroup of participants using amyloid PET at 6 months of treatment. This analysis evaluated the subcutaneous formulation in an open-label extension (OLE) of the Clarity-AD study, which included 72 participants who received lecanemab for the first time as the subcutaneous formulation and 322 participants who received intravenous lecanemab in the Clarity-AD core study followed by subcutaneous administration. In addition, lower systemic injection rates were observed with subcutaneous administration compared to intravenous administration and the incidence of ARIA-E (Amyloid-related imaging abnormalities - cerebral edema) was similar with both administrations.
The company plans to submit a biologics license application for the subcutaneous formulation to the FDA by March 31, 2024. Eisai also presented results from the optional Tau PET substudy. In the low-tau subpopulation, which is in the earlier stages of early AD, 76% of the participants who received lecanemab showed no deterioration and 60% showed clinical improvement after 18 months of treatment in the primary endpoint, Clinical Dementia Rating - Sum of Boxes (CDR-SB), compared with 55% and 28% of the placebo group, respectively. In the open-label extension of Clarity-AD, participants continued to received treatment for 24 months.
In the 18-month core study, findings showed a statistically significant difference in global cognition and function as measured by CDR-SB between the lecanemab and placebo groups. Differences between treatment and placebo across clinical end points increased over time during the first 18 months. The separation in CDR-SB between the group that continued to receive lecanemab (early start group) and the group who switched from placebo to lecanemab (delayed start group) was maintained during the 6-month open-label extension following the 18-months core study.