Eisai seeks FDA approval for monthly IV Leqembi after subQ filing

Eisai and Biogen have filed a new application with the FDA for their Alzheimer's medication, Leqembi (lecanemab), aiming to secure approval for a monthly intravenous (IV) maintenance dosing schedule. The companies believe that if this new regimen is approved, it could offer sustained clinical and biomarker benefits through a simpler, less burdensome once-monthly dose. The FDA's decision on this application is expected by January 25 of next year.

This recent FDA filing follows a rolling submission by Eisai and Biogen for a subcutaneous version of Leqembi designed for weekly self-administration. The introduction of a more patient-friendly form of the drug is expected to enhance its uptake, which has been slower than anticipated since its full FDA approval last year. This approval was based on data from the Phase III Clarity AD trial.

Earlier in the year, Eisai revealed that fewer than 4,000 patients had been treated with Leqembi, which was significantly below their target of 10,000 patients by the end of the fiscal year 2023. Nevertheless, Biogen's financial results in April showed an encouraging increase in Leqembi sales, which peaked at $19 million in the first quarter—almost three times the sales reported in the previous quarter.

Currently, the recommended protocol for Leqembi involves an IV infusion administered over approximately one hour, once every two weeks. The proposed monthly maintenance regimen would commence after patients have undergone the biweekly IV initiation phase, with the goal of sustaining the clearance of highly toxic protofibrils. The exact length of the biweekly initiation phase is still under discussion with the FDA.

The supplemental application relies on data modeling from both the Clarity AD trial and a Phase II trial called Study 201, along with their respective open-label extensions. According to Eisai and Biogen, this data has shown that continued treatment with Leqembi beyond the 18-month core phase results in prolonged benefits as it continuously removes highly toxic protofibrils.

This announcement arrives at a pivotal time, coinciding with an FDA advisory panel meeting for Eli Lilly's competing anti-amyloid drug, donanemab. The theoretical advantage of donanemab is that patients might be able to discontinue treatment once their amyloid plaques fall below a specific threshold. However, FDA scientists have raised some concerns about donanemab, particularly regarding its dosing strategy, as detailed in recent briefing documents.

Through these efforts, Eisai and Biogen are striving to make Leqembi a more viable and less cumbersome treatment option for Alzheimer's disease, potentially improving patient adherence and overall treatment outcomes. The outcome of the FDA’s review will be closely watched by both the medical community and stakeholders as it could significantly impact the landscape of Alzheimer's treatments.