Here we go again: Eisai starts rolling FDA approval submission for Biogen-partnered Alzheimer's drug

Biogen and Eisai are once again trying to get accelerated FDA approval for an Alzheimer’s disease drug candidate. Having reset the bar to U.S. market access with Aduhelm, the partners have begun a rolling submission for another anti-amyloid beta antibody in early Alzheimer’s patients.

The prospect, lecanemab, is in an ongoing phase 3 clinical trial, but Eisai wants to secure accelerated approval on the strength of midphase data. Eisai and Biogen presented phase 2 data on lecanemab, also known as BAN2401, in 2018, linking the antibody to a dose-dependent drop in amyloid plaques and a slowdown in cognitive decline.

Back then, the midphase data were seen as the key to phase 3, not accelerated approval. But the FDA decision to grant accelerated approval to Aduhelm rewrote the rules, leading Eisai to try to bring lecanemab to market before wrapping up a pivotal late-phase trial designed to show clinical efficacy.

The submission will include data from the 856 participants in the phase 2 clinical trial and the 180 people who took part in an open-label extension, as well as blinded safety results from the ongoing phase 3 trial. 

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Eisai expects to complete the application in “the next few months,” according to Reuters, suggesting it will have everything with the FDA around the turn of the year. Lecanemab has breakthrough status, making it eligible for priority review, but even so the PDUFA date could land close to the delivery of data from the phase 3 trial that will show whether the drug improves clinical outcomes. lists the primary completion date for the study of almost 1,800 early Alzheimer’s patients as Sept. 8, 2022, several months later than Eisai previously aimed to wrap up the trial but still likely in time to present results in the fourth quarter. 

The upshot is the FDA may face the question of whether to grant accelerated approval to lecanemab shortly before Eisai has pivotal data that could raise big concerns with whatever position the agency takes. In theory, the FDA could give accelerated approval to lecanemab on the strength of biomarker data only for the phase 3 to show the drug fails to improve clinical outcomes just months later. Eisai said the FDA will accept the phase 3 trial as the confirmatory study for lecanemab.

Lecanemab’s FDA review looks set to overlap with the agency’s assessment of Eli Lilly’s donanemab. After seeing the FDA grant accelerated approval to Aduhelm, Lilly set out plans to file with the FDA on the strength of midphase data.