Eisai and Biogen’s injectable Alzehimer drug faces setback from the FDA

First, due to the burden on its patients and healthcare infrastructure, and now with the Food and Drug Administration’s (FDA) demand that they submit an additional 3 months of data for the subcutaneous version of their currently infused Alzheimer’s disease drug Leqembi, it is no longer feasible for Eisai and Biogen to make good on their promise of ensuring that their drug be brought to the reach of 10,000 patients by the end of March this year.

Analysts have long thought of Leqembi as the turning or inflection point of Eisai and Biogen’s company trajectory and have been eagerly awaiting an injectable version of the company’s drug, with the hope that the new version would be more convenient to administer.

Eisai and Biogen were making good headway on this front; the companies had filed for FDA approval for the use of the drug as a monthly intravenous maintenance treatment with the hope that the bioequivalence on pharmacokinetics and similar brain plaque reduction data would be enough for an FDA application.

These hopes were dashed, however, when the agency asked for more immunogenicity analyses. This additional analysis asks for a maintenance dose of 360 mg weekly, but since the companies can’t provide this data immediately, this means that their original plan of starting a rolling submission in March as they collect the additional data has to be rethought.

The agency has mandated a fast-track designation for the intravenous formulation if the company wants to enjoy the privilege of a rolling review. This not only has to be separate from the infused versions but also means that Eisai, the company leading the efforts for Leqembi, will have to first request that new designation. It can take up to 60 days after the March submission for the FDA to reach a verdict in this regard.

The reason behind the desire for the shift from the more frequent infusion system to the subcutaneous version is so that the burden of the logistics of the diagnosis and treatment can be alleviated.

The launch of the antibody has currently been at a relatively disappointing pace since presently the drug needs to be infused every two weeks.

According to William Blair analysts, any delays in the subcutaneous of the drug are mere technicalities but that cannot deny that this recent pushback has moved potential filing for the drug to the second half of this year. If the FDA does not approve the fast-track designation, this timeline is expected to extend even longer.

Analysts at William Blair explained how, “These are technicalities in our view and do not undermine the potential of Leqembi, but they are disappointing delays for Biogen, which clearly needs to demonstrate better execution to improve investor sentiment.”

Already, due to procedural reasons, Leqembi’s application could not be discussed by reviewers at the European Medicines Agency where it was scheduled to be presented last month.

Amidst this trouble, Eisai and Biogen are at least consoled by the fact that they are not under immediate threat by competitors since the FDA has also postponed its ruling over Eli Lilly’s rival drug donanemab.