Biogen Inc. revived plans on Tuesday to seek U.S. approval for the Alzheimer¡¯s treatment aducanumab and said data from more patients in two discontinued studies showed the drug reduced the decline of patients.

The drugmaker¡¯s shares soared 27 percent in New York trading, recouping almost all of the $18 billion it lost when it said in March it was abandoning the two studies. Shares in Eisai Co., Biogen¡¯s Japanese partner in the drug, were quoted up 18 percent to the daily limit high of ?6,534 in Tokyo trading.

The field of experimental Alzheimer¡¯s treatments is littered with high-profile failures, with many major drugmakers abandoning the race to develop a medicine for a disease that makes up 60 to 70 percent of an estimated 50 million dementia cases globally.