Eli Lilly and Co says a small trial of its experimental Alzheimer's drug found that it slowed by about a third the rate of decline in a combined measure of cognition and function in patients at an early stage of the mind-wasting disease.
The drug, donanemab, is an antibody designed to remove clumps of the protein beta amyloid from the brain, which is believed to be a contributing cause of Alzheimer's.
Analysts said the findings help validate the idea that the plaques play a key role in Alzheimer's.
Donanemab targets a type of beta amyloid known as N3pG, which Lilly believes can be rapidly cleared, enabling precise treatment of patients until their plaques are removed.
Patients in the study stopped receiving monthly infusions of the drug and were switched to a placebo once their brain plaques reached levels seen in healthy people - a process that took just a few months for some.
"This study shows that the presence of amyloid is an important accelerant of Alzheimer's disease," Daniel Skovronsky, Lilly’s chief scientific officer, told Reuters.
He also said the results indicate that "this is as far as you can go with amyloid" and that additional strategies are needed to fully combat the disease.
A brain swelling side effect, known as ARIA-E, occurred in 27% of patients treated with donanemab, Lilly said.
"Alzheimer's disease is uniformly fatal ... I think this safety profile matched with this efficacy profile is something that we can be excited about," Skovronsky said.
Lilly said the mid-stage trial of 272 patients met its main goal of showing a statistically significant change in clinical decline over 18 months. It said results for the trial's secondary goals measuring cognition and function were positive, but not all of them reached statistical significance.
The company is continuing to study the drug in a second, 500-patient trial.
Lilly and Biogen are among the last large drugmakers pursuing treatments for Alzheimer's, which afflicts nearly 6 million Americans and more than 40 million people worldwide.
Any Alzheimer's treatment that can alter the course of the disease is likely to be a multibillion-dollar product, but the field is littered with more than 100 failures, including many that targeted beta amyloid.
The U.S. Food and Drug Administration is reviewing Biogen's application for aducanumab, which, if approved, would be the first new treatment for the memory-robbing disease in decades.
Biogen has said one of two pivotal aducanumab studies showed a statistically significant benefit in slowing cognitive and functional decline, but a second trial found that the drug helped only patients who got a high dose for at least 10 months.
Lilly's findings "bode well for Biogen's aducanumab, which has a similar mechanism of action," Guggenheim Partners analyst Yatin Suneja said in a research note.
Full results of the trial will be presented at a future medical meeting and submitted for publication in a peer-reviewed journal, Lilly said.© Thomson Reuters 2021.