Biogen, Eisai Alzheimer's drug lecanemab fast tracked by FDA

Biogen and Eisai head towards the end of the year with some much-needed good news in their Alzheimer's programmes, as the FDA awards a fast-track designation to lecanemab, their follow-up to recently approved Aduhelm.

The anti-amyloid drug, which also claimed a breakthrough tag from the FDA in July, is being developed for the treatment of early-stage Alzheimer's disease.

Biogen and Eisai started a rolling submission for lecanemab (formerly BAN2401) with the FDA in September, based on the results of a phase 2 trial – Study 201 – that showed a dose-dependent reduction in amyloid plaques in the brain that are a feature of Alzheimer's, as well as a slowdown in cognitive decline.

The two partners are also running a phase 3 trial called Clarity AD, with results due next year, as they try to tap into the accelerated approval pathway that allowed Aduhelm (aducanumab) to claim an FDA approval earlier this year.

In a statement, Biogen and Eisai said that the FDA has agreed that Clarity AD "can serve as the confirmatory study to verify the clinical benefit of lecanemab."

They will be hoping that lecanemab will not become mired in the controversy that engulfed Aduhelm from the moment it was approved.

The first-in-class therapy has been hit hard by questions about validity of amyloid clearance as a surrogate marker for efficacy in Alzheimer's, data on cognition, and its potential to cause serious side effects, which have held up approvals in Europe and Japan.

The $56,000-a-year price tag for the drug, which has now been cut in half in the US, also hasn't helped the drugmakers make a case for Aduhelm with US payers.

Biogen and Eisai are also running another phase 3 clinical study – AHEAD 3-45 – which is evaluating intravenous lecanemab in people with preclinical Alzheimer's and elevated amyloid levels.

Additionally, Eisai has started a phase 1 trial of a subcutaneous formulation of lecanemab that could be suitable for dosing outside clinics.

Other amyloid-targeting drugs are also trying to follow Aduhelm to market with accelerated approvals, including Eli Lilly's donanemab and Roche's gantenerumab, which are also expecting key data readouts in 2022.