Biogen loses aducanumab gains after disastrous FDA panel vote

US biotech Biogen (Nasdaq: BIIB) gained 44% on Wednesday of last week when the US Food and Drug Administration (FDA) posted encouraging briefing documents on the company’s aducanumab filing for members of the Peripheral and Central Nervous System (PCNS) Drugs Advisory Committee Meeting.

The papers, which referenced three studies, two of them large, international pivotal trials, appeared to make a case for approving the amyloid-beta targeting antibody as a treatment to delay clinical decline in patients with Alzheimer’s disease.

But by lunchtime on Monday, Biogen shares had plunged by 30%, undoing much of the previous week’s gain, after Friday’s committee vote on the filing.