FDA Extends Its Aducanumab Review With Decision Expected in June

The U.S. Food and Drug Administration (FDA) has extended its review period for aducanumab (BIIB037), an investigational therapy for Alzheimer’s disease being co-developed by Biogen and Eisai.

The three-month extension means the new deadline to review the compound’s biologics license application (BLA), also known as the Prescription Drug User Fee Act action date, is June 7, 2021.

“We are committed to working with the FDA as it completes its review of the aducanumab application,” Michel Vounatsos, Biogen’s CEO, said in a press release. “We want to thank the FDA for its continued diligence during the review.”

Aducanumab is a synthetic, or man-made, antibody designed to remove the misshapen beta-amyloid proteins, whose toxic clumps lead to the death of nerve cells (neurons) seen in the brains of those with Alzheimer’s. By targeting a region of beta-amyloid that is only accessible when the proteins clump together, the antibody is expected to leave healthy beta-amyloid unaffected.

If approved, it would become the first therapy to potentially slow Alzheimer’s progression.

The experimental therapy’s path to approval has been tumultuous.

Two Phase 3 trials of aducanumab — ENGAGE (NCT02477800) and EMERGE (NCT02484547) — were terminated in 2019, after an independent advisory committee determined that the investigational medication was unlikely to provide patients with a meaningful benefit.

However, an analysis of a larger dataset, which became available after trial termination, indicated that EMERGE had, in fact, achieved its main goal of improving cognition and function, including memory, orientation, language, and daily living activities, relative to a placebo.

Based on this and the results of the Phase 1b PRIME study (NCT01677572), which showed evidence that aducanumab could slow cognitive decline, Biogen and Eisai asked the FDA, as well as its European counterpart, the European Medicines Agency, to consider approving aducanumab.

The companies later submitted their BLA for the potential therapy to the FDA, which granted it priority review.

During this review period, an FDA advisory committee determined that the available clinical data did not support aducanumab’s effectiveness in treating Alzheimer’s. The FDA is expected to consider the committee’s votes but is not bound to agree with them.

As part of the ongoing review, Biogen submitted additional analyses and clinical data as requested by the FDA. The agency classified it as a “Major Amendment” to the medication’s application, which requires that the review period be extended.

In addition to the U.S. and Europe, aducanumab’s developers are also seeking approval in Japan.