Shares of Biogen and other drugmakers researching Alzheimer's disease soared early Wednesday after Japan's Eisai Co. said its potential treatment appeared to slow the deadly disease in a late-stage study.
The drugmaker said early results showed its treatment, lecanemab, reduced a patient's clinical decline by 27% compared to a placebo or dummy drug after 18 months of infused treatment.
Eisai announced the results Tuesday night of a global study of nearly 1,800 people with early-stage Alzheimer's.
The patients were monitored using a scale that measures mental decline and their ability to perform daily activities such as dressing or eating.
Eisai Co. Ltd. said it would discuss the full results of the investigation at a conference in late November. It also plans to publish the findings in a peer-reviewed medical journal.
The company is already seeking expedited approval from the US Food and Drug Administration, with the agency expected to make a decision early next year. Eisai and Biogen will co-promote the drug.
Researchers often urge caution when evaluating a study until the full results are published. But the initial findings appear to be "pretty strong" and will likely support regulatory approval, Graig Suvannavejh, an analyst at Mizuho Securities, said in a research note.
A statement from the Alzheimer's Association called the findings the most encouraging to date for possible treatments of the underlying causes of the disease.
Some 6 million people in the US and many more around the world have Alzheimer's disease, which gradually attacks areas of the brain needed for memory, reasoning, communication, and basic daily tasks.
Alzheimer's has no known cure. Long-standing treatments on the market only control symptoms, and researchers don't fully understand what causes the disease.
Last year, adhelm from Biogen became the first new Alzheimer's drug introduced in nearly two decades. But it largely flopped after debuting at a price of $56,000 annually, which Biogen later cut.
Doctors have been hesitant to prescribe it, given weak evidence that the drug slows the progression of Alzheimer's disease. Insurers have blocked or restricted coverage due to concerns about the drug's high price and uncertain benefit.
Earlier this year, the federal Medicare program placed strict limits on who can get the drug, killing most of its potential market in the US Biogen later announced it would stop most of its spending on the treatment.
Like Aduhelm, lecanemab, developed by Eisai, aims to remove a protein called beta-amyloid from the brain.
The protein forms a plaque that researchers believe contributes to Alzheimer's. They also point to other potential factors such as family history and chronic diseases such as diabetes.
Eisai executives say lecanemab targets more of the protein's floating clumps before it forms plaque, which is what Aduhelm is targeting.
Eli Lilly and Co. is also developing a potential treatment, donanemab, that targets the protein.
Shares of Cambridge, Massachusetts-based Biogen Inc. were up 35% at $267.29 in Wednesday morning trading as broader indexes rose. Shares had fallen heavily since Aduhelm's debut last year.
Shares of Indianapolis-based Eli Lilly and Co. rose more than 8%