Eisai, Biogen Resubmit Subcutaneous Leqembi to FDA After Setback

Eisai and Biogen have initiated a rolling submission for the marketing application of the subcutaneous (SC) version of Leqembi (lecanemab) for the maintenance treatment of early Alzheimer's disease (AD), following their receipt of the FDA’s fast-track designation. The original intravenous (IV) version of Leqembi had previously received fast-track status, but the FDA clarified that this did not cover the new SC formulation, necessitating a new regulatory submission. The submission, originally planned for March, was delayed when the FDA requested an additional three months of immunogenicity data for the SC version from Eisai. According to UBS analysts, this delay suggests that a decision might be made in the latter half of next year.

The marketing application is supported by open-label extension studies and data modeled from the Phase III Clarity AD study. The SC autoinjector version of Leqembi is expected to facilitate quicker administration of the anti-amyloid-beta antibody, either at home or in medical settings, compared to the IV version. The SC version also offers the benefit of a weekly maintenance regimen, which is likely to maintain effective drug levels after the initial biweekly IV doses.

A FirstWord poll among neurologists revealed strong support for the SC version, with 62% of respondents considering it superior to the IV form. They also foresee better accessibility to the drug, particularly in underserved rural regions. Approval of the SC formulation could represent a substantial victory for Eisai and Biogen, who have faced challenges in increasing global adoption of Leqembi. As of March, less than 4000 patients had been treated with Leqembi, significantly short of their target of 10,000 patients by the end of 2023. Despite the challenges, Biogen’s latest earnings report showed promising signs, with Leqembi sales reaching $19 million in the first quarter—almost tripling the sales from the previous quarter.