Eisai Wins US Approval of Alzheimer’s Drug With Restrictions (1)

Eisai Co.’s breakthrough Alzheimer’s disease drug Leqembi gained full approval in the US. Yet, testing requirements and side effect warnings that may limit its use sent the company’s shares sliding.

The Food and Drug Administration decision marks a milestone, as Leqembi is the first drug shown to slow progression of the mind-robbing disease that afflicts some 6 million Americans. While the drug developed with Biogen Inc. was granted expedited authorization in January, the traditional approval was expected to spur greater insurancecoverage of the medicine that costs $26,500 a year.

It came with unexpected restrictions, however. MRI scans are ...