The Food and Drug Administration is already limiting one of the most controversial drug approvals in its 115-year history.
The medication is Biogen Inc.'s Alzheimer's treatment Aduhelm, which won clearance recently despite mixed evidence and expert objections. The agency initially approved the drug for most Alzheimer's patients, even though it was only studied in those with mild disease.
The decision risked bringing an expensive treatment to millions of additional patients without evidence of utility or safety. The FDA has now changes its prescription guidelines to suggest using the drug only in the smaller group in which it was studied. The initial approval was so inexplicably broad that investors reacted favorably to the restriction.