It's been nearly two years since Biogen announced it would seek federal approval for its drug, aducanumab, to treat some people in the early stages of Alzheimer's disease. And by June 7, the U.S. Food and Drug Administration (FDA) will decide whether it plans to bring the medication to market.
The process hasn’t been free from controversy, though. The fate of the drug suffered a serious blow back in November, when an FDA-convened panel of outside experts expressed concern over the data backing aducanumab’s effectiveness. The FDA does not have to follow the recommendations of the advisory panel, but it typically does.
If approved, aducanumab would be the first new Alzheimer's treatment in 17 years and the only one that reduces cognitive decline by tackling an underlying cause of the disease, not just its symptoms. It works by targeting the buildup of toxic amyloid plaques, which disrupt cell function in the brain and are a hallmark of Alzheimer's disease. Several other drugs have attempted to target amyloid, but none have succeeded yet.
"We've been waiting for a disease-modifying therapy; I've been waiting for it for decades,” says Richard Isaacson, M.D., director of the Alzheimer's Prevention Clinic at Weill Cornell Medicine and New York-Presbyterian.
Aducanumab is not a cure for Alzheimer's, experts stress, and if it's approved, it won't be available to everyone who has the disease. But its authorization would signify progress in a long pursuit to bring help to the more than 6 million older Americans suffering from the debilitating condition.
"[It] would be a victory for all of those individuals living with Alzheimer's and their families,” says Joanne Pike, chief strategy officer of the Alzheimer's Association.
The bumpy, winding road toward approval
Aducanumab's development has been fraught with concerns and setbacks. Months before Biogen made the decision to seek FDA approval, the company went so far as to scrap its late-stage testing of the drug. Aducanumab's two identically designed clinical trials were both stopped in March 2019 because an early analysis showed the drug was unlikely to be effective.
However, hopes were resurrected when a subsequent analysis of a larger set of data from the trials, conducted after testing ended, found that in one study, participants who received high doses of aducanumab actually experienced improvements in memory, cognition and activities of daily living. Results from the other trial were less convincing, although Biogen says an analysis of a narrower set of data from that trial also found evidence of improvement among participants. The discrepancies in the data from the two trials are what the FDA advisory panel homed in on and expressed concern over in its Nov. 6, 2020, meeting.