Alzheimer’s Drug Poses a Dilemma for the F.D.A.

And some experts, like Dr. Ronald Petersen, director of the Mayo Clinic’s Alzheimer’s Disease Research Center in Rochester, Minn., say they’re “on the fence.” He said he’d like to give patients a new option soon but “the data are iffy.”

Aducanumab, a monoclonal antibody, targets a protein, amyloid, that clumps into plaques in the brains of Alzheimer’s patients. Many amyloid-reducing drugs failed to slow symptoms in trials, a history that, some experts say, makes it especially important that aducanumab’s data be convincing. If effective, it would support a long-held, unproven theory that attacking amyloid can help if done early enough.

Excitement about aducanumab grew after a small early trial to evaluate safety showed amyloid reduction and hinted it might slow cognitive decline. The F.D.A., in a move some experts question, allowed Biogen to skip Phase 2 trials and conduct two Phase 3 trials of about 1,640 patients each.

Both trials were stopped early, in March 2019, when an independent data monitoring committee said aducanumab didn’t appear to be working. Consequently, 37 percent of participants never completed the 78-week trials.

But that October, Biogen announced it found benefit in one trial after evaluating data from 318 participants who finished before the trials were stopped but after the cutoff point for results the monitoring committee assessed.

In that trial, Biogen said, the highest dose slowed cognitive decline by 22 percent, or about four months over 18 months. A lower dose in that trial and high and low doses in the other showed no statistically significant benefit over a placebo.

Article source: https://www.nytimes.com/2021/06/05/health/alzheimers-aducanumab-fda.html