A pharmaceutical company that discontinued two late-stage studies of an Alzheimer’s drug earlier this year shared new data Thursday explaining how high doses of the experimental medication might slow decline in patients.
Biogen halted two phase-three studies of the drug aducanamab in March because early analysis found that it did not appear to work. However, the company shocked investors and Alzheimer’s researchers in October when it said a new analysis showed the drug appeared to work in a subset of patients.
In a presentation at the Clinical Trials on Alzheimer’s Disease meeting in San Diego, Biogen shared the data and explained a midstudy change to a higher-dose version of the amyloid-targeting drug might have helped a subset of patients.
One of the two studies, called Emerge, appeared to meet a goal of slowing decline in patients, according to the data shared by Samantha Budd Haeberlein, Biogen’s vice president of clinical development. The second study, called Engage, failed.
Shares of Biogen closed up more than 3% in trading Thursday after the company released the new data.
The company previously said that based on the new analysis, it would seek Food and Drug Administration approval for the drug next year.
“This is a milestone achievement for our field,” said Stephen Salloway, a Brown University professor of psychiatry and neurology, who was part of a panel discussing the aducanamab’s study results.
An estimated 5.8 million Americans have Alzheimer’s disease, the most common form of dementia.
Drug companies for decades have developed drugs targeting deposits of the protein amyloid in the brain on the theory it is responsible for scuttling memory and thinking in Alzheimer’s patients. But dozens of drugs designed to clear or inhibit the protein’s growth have failed, leading some to question whether amyloid is even the right target.
That’s one reason Alzheimer’s researchers are closely watching aducanamab, which in early studies showed promising results, only to be discontinued in March and revived in October.
“If the findings are confirmed, it would have a major impact in the fight against Alzheimer’s disease,” said Dr. Eric Reiman, a researcher and executive director of Banner Alzheimer’s Institute in Phoenix. “It would provide a clinically meaningful treatment for affected patients, and it would provide support for targeting amyloid.”
Budd Haeberlein said early studies of the drug showed people with the Alzheimer’s risk gene APOE4 had signs of amyloid related imaging abnormalities, or brain swelling, at higher doses. For people who carried this gene, the study initially limited doses of the medication to six milligrams per kilogram of body weight.
But researchers changed the study’s protocol in March 2017, allowing APOE4 carriers to take the highest dose of 10 milligrams per kilogram. The study concluded the higher-dose aducanamab reduced clinical decline in people in the Emerge study, but the same doses failed in the Engage study.
That will leave the FDA to consider companion studies terminated early with uneven results.
Paul Aisen, a University of Southern California neurologist and Alzheimer’s researcher, said the results are complex.
The March decision to halt the studies was “highly unfortunate and puts us in the situation of interpreting complex data,” he said. Yet other evidence such as the reduction of amyloid, was a “hugely important result and it represents a major advance for the field.”