Alzheimer’s drug shows promise in early results of study

Shares of Biogen and other drugmakers researching Alzheimer’s disease soared Wednesday after Japan’s Eisai Co. said its potential treatment appeared to slow the fatal disease in a late-stage study.

The drugmaker said early results showed that its treatment, lecanemab, reduced patient clinical decline by 27% when compared to a placebo or fake drug after 18 months of the infused treatment.

Eisai announced results late Tuesday from a global study of nearly 1,800 people with early-stage Alzheimer’s.

Patients were monitored using a scale that measures mental decline and their ability to...