Biogen Inc. surged the most in seven years after an Alzheimer's drug showed positive results in a large clinical trial, raising hopes for treatment of a disease that has befuddled researchers for decades.
Alzheimer's progressed more slowly for patients who got the highest dose of the experimental drug, BAN2401, Biogen and its Japanese partner Eisai Co. said in a press release. The results, which came after 18 months of treatment, took investors by surprise. The companies reported a failure in December, based on data on 12 months of treatment.
Biogen did not give any numbers showing how much the treatment affected the ability of the patients to function, or how the level of amyloid in the brains of the patients receiving BAN2401 compared with the level of brain amyloid in the patients in the control group.
Biogen did say, in the press release, that a final analysis of 18 months of results "demonstrated statistically significant slowing in clinical decline and reduction of amyloid beta accumulated in the brain… Further, the highest treatment dose of BAN2401 began to show statistically significant clinical benefit … as early as 6 months, including at 12 months."
While the ultimate outcome remains far from certain, the study is a bright spot — if a tenuous one — in the search for a treatment for Alzheimer's, where more than 100 experimental drugs have failed. Drugmakers have persisted in part because of the size of the potential market — as much as $30 billion in the U.S. alone, according to Sanford C. Bernstein & Co. analysts.
Any drug company successes at preventing, curing or slowing the progression of Alzheimer's could also have a big effect on the private long-term care insurance (LTCI) market. One securities analysts estimated in 2015, for example, that dementia might account for about 50% of LTCI claim costs at Genworth Financial Inc.
The success of BAN2401 will depend on the details of the data, set to be presented at a medical meeting, according to Bloomberg Intelligence analyst Sam Fazeli.
The dearth of good news in Alzheimer's has whetted investors' appetite for positive results. But many analysts pointed to the unknowns about the trial at this stage. The study is in phase 2, or mid-stage, and the data would need to be validated in broader testing.
"The question is, is it real?" Fazeli said. "When we see the data, will the room be filled with oohs and aahs, or will the room say, 'oh my god, not again?'"
Eisai said it will talk to regulators about how to proceed with the next step in development.