TOKYO (Reuters) - Eisai Co Ltd's shares were untraded on Friday, hit with a glut of sell orders after the Japanese drugmaker and its partner Biogen Inc said they are ending two drug trials of their experimental Alzheimer's disease drug aducanumab.
The decision, which wiped $18 billion off the value on Biogen on Thursday, marks a major setback in the quest to find a treatment for the mind-wasting disease and came after experts determined the trials had little hope of succeeding.
Eisai shares were hit with sell orders at 7,565 yen, down nearly 17 percent from Wednesday's close of 9,065 yen, the most it could fall on Friday under exchange rules. Japanese markets were closed for a national holiday on Thursday. Sell orders dwarfed buy orders by about 30 times.
The setback comes as the two drugmakers face scepticism from investors over their experimental Alzheimer's drug, BAN2401, for which they reported promising but confusing 18-month results last July.
Dozens of experimental drugs have failed in the race to treat Alzheimer's, the most common form of dementia. Thursday's announcement pushed down Biogen's shares nearly 30 percent, its largest drop since February 2005.
(Reporting by Sam Nussey and Chang-Ran Kim; Editing by David Dolan)